# D. Gray D&D - HEAVY DUTY KNURLING TOOL KIT



## YYCHM (Aug 15, 2022)

This arrived today.... Ordered on the 11th.  $124.39 shipped.  https://d-gray-drafting-and-design.myshopify.com/






It was certainly well packaged.....


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## PeterT (Aug 15, 2022)

Look forward to your build & testing. I cant figure out the knurled tension knob on these styles. I have limited experience but I've used:
- bump style knurlers ( work fine but too hard on parts & machine IMO)
- a very poorly made Asian contraption (not even worth mentioning)
- an Armstrong (USA made scissor style), decent but has some shortcomings IMO
- AccuTrak (better USA made  scissor style). Both USA models presumed some kind of wrench to apply enough force on the scissor action & arguably had higher leverage mechanics relative to axle & wheel. Same deal for the Doug Ross knurler I attached YouTube link for in the other post.

I'm not picking on this design in particular because I have seen several variants in model engineering circles. But I'd be interested in how this style works with (only) finger torque tensioning. Do the instructions infer running the knurl back & forth with increasing tension or....?


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## Dusty (Aug 15, 2022)

@YYCHM  hey Craig did you get the metric kit or imperial kit?  I assume the latter.


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## YYCHM (Aug 15, 2022)

PeterT said:


> Look forward to your build & testing. I cant figure out the knurled tension knob on these styles. I have limited experience but I've used:
> - bump style knurlers ( work fine but too hard on parts & machine IMO)
> - a very poorly made Asian contraption (not even worth mentioning)
> - an Armstrong (USA made scissor style), decent but has some shortcomings IMO
> - AccuTrak (better USA made  scissor style). Both USA models presumed some kind of wrench to apply enough force on the scissor action & arguably had higher leverage mechanics relative to axle & wheel. Same deal for the Doug Ross knurler I attached YouTube link for in the other post.



I have one of these https://www.busybeetools.com/products/adjustable-knurling-tool-holder.html and a bump knurler that came with my QCTP set.  The  joints in the BB knurler are soo loose the whole thing leans way over when you travers.  Both produce a knurl but not the best IMHO.


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## YYCHM (Aug 15, 2022)

Dusty said:


> @YYCHM  hey Craig did you get the metric kit or imperial kit?  I assume the latter.



Imperial.  Now I have to source a 5/16-24 tap and a 5/16 reamer


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## Dusty (Aug 15, 2022)

YYCHM said:


> Imperial.  Now I have to source a 5/16-24 tap and a 5/16 reamer



Hey Craig you mean to say holes are not drilled or tapped? Why do you require the reamer? Kindly fill in the planks as there may be others interested in obtaining a kit. Just saying!


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## YYCHM (Aug 15, 2022)

PeterT said:


> Do the instructions infer running the knurl back & forth with increasing tension or....?


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## YYCHM (Aug 15, 2022)

Dusty said:


> Hey Craig you mean to say holes are not drilled or tapped? Why do you require the reamer? Kindly fill in the planks as there may be others interested in obtaining a kit. Just saying!



All the raw stock and screws are supplied with the full kit.  You have to do all the drilling, reaming, tapping and thread the 5/16-24 tension rod.  There is a little bit of lathe turning and some milling.  The plans and build notes look pretty good.


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## Proxule (Aug 15, 2022)

Watching, Thanks!


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## Degen (Aug 15, 2022)

Or 






						KBC,KBC SMALL KNURLING TOOL 0-2.1/8 IN.,1-587X-1000,KBC Tools & Machinery
					

KBC,KBC SMALL KNURLING TOOL 0-2.1/8 IN.,1-587X-1000,KBC Tools & Machinery




					www.kbctools.ca
				




Choice to make, the journey and experience getting there or start working with it.

Sorry couldn't resist.


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## jcdammeyer (Aug 15, 2022)

Looking forward to seeing the results.


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## Six O Two (Aug 16, 2022)

PeterT said:


> I'm not picking on this design in particular because I have seen several variants in model engineering circles. But I'd be interested in how this style works with (only) finger torque tensioning. Do the instructions infer running the knurl back & forth with increasing tension or....?



I generally bring my scissor-style knurler up to the work so that the two wheels are just shy of being on the diamater axis of the workpiece, finger tighten, and then use the cross-slide to roll the now tight wheels onto the center of the piece. Dunno if that's how you're supposed to do it, but it's worked for me.


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## PeterT (Aug 16, 2022)

I can see that cross slide technique accomplishing the right seating effect for knurl wheels & material. Maybe a downside is it puts additional pressure (wear) on your leadscrew/nut.


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## Tom O (Aug 16, 2022)

I wonder about this pressure on the lead screw while people are bragging about 100 - 150 + depth of cut using said screw and not concerned about pressure. I realize the scissor knurler is better than the direct push in type.


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## RobinHood (Aug 16, 2022)

Tom O said:


> I wonder about this pressure on the lead screw while people are bragging about 100 - 150 + depth of cut using said screw and not concerned about pressure.


So was I until I found some numbers which set my mind at ease…

Let’s assume that most hobby size machines have compound lead screws of 1/2-10 Acme (the cross slide and the carriage lead screws would most likely be bigger). Most have steel screws with a bronze/brass nut. So the nut would be the limiting factor.

Here is what roton (not affiliated) has to say about their bronze nuts (and they list other materials as well).






I would assume that during most cutting / knurling operations the compound (as well as the cross slide) would be stationary. So, static load is 4000 lbs and operating load is 1250 lbs for a 1/2-10 Acme.

The problem is most likely not the lead screw/nut; it is a lack of rigidity of the smaller machines.

Here is the link to the roton website:





						Acme Lead Screws & Nuts - Engineering Data | Roton Products Inc.
					

Engineering data for our acme lead screws & lead screw nuts. Roton Products is a manufacturer of high quality Acme Lead Screws, Lead Screw Nuts, and more.



					www.roton.com


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## VicHobbyGuy (Aug 16, 2022)

RobinHood said:


> I would assume that during most cutting / knurling operations the compound (as well as the cross slide) would be stationary. So, static load is 4000 lbs and operating load is 1250 lbs for a 1/2-10 Acme.


@RobinHood - thanks for that info. 
I don't understand the 'Operating load' parameter. Suppose a 1250 lb load was suspended from the nut and the steel screw was wound to raise the load. How long would the bronze nut last, and what would the wear rate be, with normal (thin coat of oil) lubrication? 
I have both push and scissor knurlers. With the scissor knurler it's impossible to get enough pressure on the knurls to knurl steel by tightening the tension knob by hand. I don't want to put Vise-Grips on the knob so I usually advance the knurls 'almost' to the working possition (straddling the work), tighten the knob as much as I can to start knurling, and then advance the cross slide to push the knurling wheels into the 'corrrect' working position. I do worry that I am causing a lot of friction and wear on the cross slide nut by doing this.


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## YYCHM (Aug 16, 2022)

Got started on the build shorty after lunch today.....






Here I'm reaming a hole in the body plate.






Here I'm drilling a hole in a cover plate (one of two).






Body and cover plates done.  This could drag on as I'm using an ER20 collet chuck for all the hole making operations.   4 collet changes if reamed,  3 collet changes if only drilled.  The laser etched hole center marks are a nice touch as it confirms the DRO  locating process. 

Next up are the 4 arm plates which will require 16 reamed holes

The plans suggest gluing two arm pates together and drilling and reaming them as a set.  I'm not sure I trust that approach.......


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## Susquatch (Aug 16, 2022)

Six O Two said:


> I generally bring my scissor-style knurler up to the work so that the two wheels are just shy of being on the diamater axis of the workpiece, finger tighten, and then use the cross-slide to roll the now tight wheels onto the center of the piece. Dunno if that's how you're supposed to do it, but it's worked for me.



I have only used pressure Knurlers to date having just only just recently acquired a scissor unit. But I generally like your approach. It makes some sense. Perhaps my only objection would be the initial push to get it over center. It might actually be better to tighten the scissors than push it over center even though it can't possibly be as bad as a regular push knurler.

So I see it as infinitely better than pushing and then perhaps some tradeoff on how to best set it up.


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## PeterT (Aug 16, 2022)

I guess I was trying to say 'unnecessary' load on the cross slide leadscrew nut, since with a scissor knurl you have a much cheaper screw built in the tool itself that accomplishes the exact same thing in a different plane. That screw is finer pitch, presumably more mechanical advantage to achieve knurl depth. It also runs in steel 'nuts', not a typical bronze ABL leadscrew nut. With bump style knurling tools you are kind of stuck with direct infeed. I've seen those easily bend 1/2" tool steel which would equate to a pretty aggressive cut. Bump style is also not kind to your tail stock assembly taking lateral force, but again, our machines vary in robustness. When I was shown bump style it was recommended that you don't creep in slowly. Supposedly kiss the rollers on the surface & then you gave it a faster dial twist in which helped set the deformation process. Not sure if this was related to a sort race against work hardening, or just how it works out. The instructors knurls were perfect sharp diamonds under magnification & everyone else's was shades of sh*t so who am I to argue. Actually most people had decent results on 12L14 but O1 was a different matter despite finer knurl pitch. Some just looked like cross hatching, those were the infeed dilly-dally-ers I recall.

As to how much accelerated wear occurs by heavy cutting in-feeding by itself, that's a great question. I have only seen tables that quantify power consumption to remove material X at rate Y. Parting in theory should be hard on leadscrews too, but maybe in reality we just feed at the rate its happy. Too much & usually something worse happens. I've been pretty average or probably light operating my lathe & its leadscrew/nut time this winter. Wear is a reality.

Good discussion. My own personal conclusion is I now want to try a cut knurler.


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## Susquatch (Aug 16, 2022)

PeterT said:


> Good discussion. My own personal conclusion is I now want to try a cut knurler.



Me too! Quite badly! Just need to find something good quality that's affordable.


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## RobinHood (Aug 16, 2022)

VicHobbyGuy said:


> How long would the bronze nut last, and what would the wear rate be, with normal (thin coat of oil) lubrication?



I don’t know what the wear rate would be. Perhaps a question for roton? Maybe there is an industry standard accepted wear rate and the 1250lbs operating load refers to that?

Just observational info: taking light cuts (both with turning tools and parting tools) seems to put more pressure on the compound/cross slide than taking a “good bite” (the DoC depends on the material properties). How do I know that? Well, after turning for a good length and returning the carriage back to the beginning of the cut, the tool seems to leave a mark (or drags) on the part with shallow DoC. Not so after a heavy cut. Could be because the tool is working more optimally with a heavier cut - don’t know.

Getting back to knurling: I have an offshore version of the one Craig is currently building. It seems to work really well (axles are a bit lose for my liking though). What I found to work well (in any material) is position the tool on the diameter with the wheels just touching. Apply lots of lube, crank the tensioning bolt quickly and firmly another 1/4 to 1/2 turn to take a real bite (one can hear it “sing”), engage the longitudinal feed and keep lubing. Full depth, one pass. Things get toasty warm, but no harm done in many years of use. Works very well.

This is a 3/4” and a 1-1/4” diameter knurl in mild steel and O1 respectively. Both have been used for 2 years (hence the dirt and slight wear off the peaks).


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## Degen (Aug 17, 2022)

RobinHood said:


> I don’t know what the wear rate would be. Perhaps a question for roton? Maybe there is an industry standard accepted wear rate and the 1250lbs operating load refers to that?
> 
> Just observational info: taking light cuts (both with turning tools and parting tools) seems to put more pressure on the compound/cross slide than taking a “good bite” (the DoC depends on the material properties). How do I know that? Well, after turning for a good length and returning the carriage back to the beginning of the cut, the tool seems to leave a mark (or drags) on the part with shallow DoC. Not so after a heavy cut. Could be because the tool is working more optimally with a heavier cut - don’t know.
> 
> ...


Operating loads are generally a factor below material deformation of either threads or nut or nut mounting.  As soon as stretch or compression starts the accuracy starts changing, exceed it by a lot, this stops, moments before failure.


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## Mcgyver (Aug 17, 2022)

A good looking project.  Peter I agree with your points, but it would be easy to replace the knurled nut with a hex nut.  When I've used them, its about no pressure on the feedscrew and nut and no infeed.  Crank the tension on the scissor and it knurls in one pass.....but that does require cranking the tension up more than the knurled nut.  ( I guess the cranking would impose some force on feedscrew and nut, but most taken by the scissor obviously.)

Maybe how I've used them isn't how this one is to be used, i.e. maybe multi pass (but I can't see a reason to)


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## GlenG (Aug 17, 2022)

Very interested in this, keep up the posts


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## YYCHM (Aug 17, 2022)

A little more progress today....







Reaming the 1/2" swivel saddle on the first side plate.  I'm finding the setup for this challenging.  Resorted to two pieces of 1/2" brass round stock one either side of the upper lobe.  Clearance space between the parallels was pretty tight.







1st side plate done, 3 more to go.  All 4 holes get reamed.  A lot of collet changes.

*UPDATE...*






I managed to get two side plate done today....


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## YYCHM (Aug 18, 2022)

Four side plates now drilled and reamed.......







Once they are reamed you mill or saw off the top lobes....






Finally each plate needs to be drilled and tapped for a 6-32 grub screw....






Unfortunately I broke my tap while attempting to tap the first one  Off to CT tomorrow.


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## PeterT (Aug 18, 2022)

Might be coincidental but if the part was laser cut, it can present issues drilling & tapping through the heat affected zone.


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## trlvn (Aug 19, 2022)

YYCHM said:


> Unfortunately I broke my tap while attempting to tap the first one Off to CT tomorrow.


"CT" as in Canadian Tire?  You might want a better quality tap.

Craig


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## cuslog (Aug 19, 2022)

I built one of those 10+ years ago, plans came from a book, spring is a good idea.
Suggestion:  Hex nut on top. On mine, it takes quite a bit of pressure on that screw, I can't imagine a brass thumb screw being able to get enough pressure (or for that matter, surviving the pressure). I'm using a 7/16" wrench to tighten up mine


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## YYCHM (Aug 19, 2022)

PeterT said:


> Might be coincidental but if the part was laser cut, it can present issues drilling & tapping through the heat affected zone.
> 
> View attachment 25605



Yes, they are laser cut and the build notes states they may have a tough outer layer to deal with.  They drilled easy enough though.


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## YYCHM (Aug 19, 2022)

cuslog said:


> I built one of those 10+ years ago, plans came from a book, spring is a good idea.
> Suggestion:  Hex nut on top. On mine, it takes quite a bit of pressure on that screw, I can't imagine a brass thumb screw being able to get enough pressure (or for that matter, surviving the pressure). I'm using a 7/16" wrench to tighten up mine



The kit comes with a hex nut that can be used instead of the brass thumb nut.


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## Susquatch (Aug 19, 2022)

trlvn said:


> "CT" as in Canadian Tire?  You might want a better quality tap.
> 
> Craig



I've been waiting for a reply on this question @YYCHM .  But I think either you forgot about it or you intended that your thumbs up meant "yes". 

Anyway, If you did mean CTire, I'm with @trlvn on this one. I gave up on cheap Crappy Tire / Amazon taps a long long time ago. They cut crappy threads, they don't cut easily, require too much force, and they break way too easily. Sometimes they even cut under or oversize threads. I buy all single high quality taps today. I can't justify full sets so I only buy them as needed.


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## VicHobbyGuy (Aug 19, 2022)

Susquatch said:


> They cut crappy threads, they don't cut easily, require too much force, and they break way too easily. Sometimes they even cut under or oversize threads.


I still have lots to learn. There was an interesting discussion on the 7x lathe group at groups.io recently on taps and tapping. 
https://groups.io/g/7x12MiniLathe/topic/taps_from_different/93012175?
I shouldn't have been surprised to learn that taps come in different sizes:
https://www.nextgentooling.com/technical/unc-unf-class-of-fit-tap-tolerance
So that probably explains some of the variation between taps in my collections.
I also didn't know that it's customary to choose the tap drill for the % thread required, generally smaller % for steel and larger % thread for softer materials. Some of the 'hard-to-tap  situations I've had resulted from too small a tap drill. BTW, I've also found that my number drills aren't always 'on spec', but I'm not about to order up a $1k set of number/letter drills from KBC - so I do more experiments and tests now. Fortunately I haven't broken a tap in many years, probably because of my timid approach and failing muscle-power! 
@YYCHM : what % thread does DGray recommend for those parts?


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## YYCHM (Aug 19, 2022)

VicHobbyGuy said:


> @YYCHM : what % thread does DGray recommend for those parts?



% thread is not specified in plans.  I went 7/64" for 6-32 as that's the closest drill bit size I have.  The CT Maximum taps suggest 7/64" as well.


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## DPittman (Aug 19, 2022)

I've had some Canadian Tire HSS tap and dies I bought many years ago that actually were not too bad.  I've also heard from others that had some positive things to say about them also.  I know their product has varied hugely over the years and have seen some garbage their also.  I think if they had actual hss tap and die set that appeared to be okay I wouldn't necessarily shy away from them anymore than any other importer.  Most lower cost tap and die sets I see now are not hss but rather high carbon steel.


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## gerritv (Aug 19, 2022)

for 6-32: #32 (0.1160) for 50% thread in steel. There is seldom any point in more thread depth. Al would be #36 (0.1065) at 75%


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## YYCHM (Aug 19, 2022)

Done.... All 4 side plates tapped 6-32....






Switched to a tap handle that provided better feel.  Lots of cutting fluid and clearing tapping swarf.  No further tap fatalities.

I've had pretty good luck with CT Maximum taps when purchased individually.  I do admit they seem kind of pricy though.  Convenience rules for me I guess.


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## VicHobbyGuy (Aug 19, 2022)

YYCHM said:


> % thread is not specified in plans.  I went 7/16" for 6-32 as that's the closest drill bit size I have.  The CT Maximum taps suggest 7/16" as well.


typo- you meant 7/64?
I like the same LMS tap drill chart that @gerritv has posted.
As he said, for steel, with 50% thread the recommended #32 drill is .116"
7/64 is .109", smaller than a #35 drill
I can definitely feel the difference that even one step in the number drill series makes when tapping.
Even my bargain number drill set is extremely useful, so I'd suggest keeping a lookout for a set on sale.
I also find it handy to have a chart listing fractional, number and metric drill sizes:


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## YYCHM (Aug 19, 2022)

VicHobbyGuy said:


> typo- you meant 7/64?



Right you are.... Me Bad


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## YYCHM (Aug 19, 2022)

Got started on the swivels today....






The round stock is supplied as a single piece, so you have to cut it half and turn the resulting pieces down to final dimension.


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## Susquatch (Aug 19, 2022)

YYCHM said:


> Got started on the swivels today....
> 
> View attachment 25623
> 
> The round stock is supplied as a single piece, so you have to cut it half and turn the resulting pieces down to final dimension.



Looks like you are gunna end up with something you can be really proud of and make good use of too!


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## YYCHM (Aug 19, 2022)

First bit of turning done....






Need two of these.






This was my setup for getting the shoulder length right.  This and the carriage stop.






This looked kind of iffy to me, but was ok taking 10 thou doc passes.






Fits the side plates like so but with the top half milled off.


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## RobinHood (Aug 19, 2022)

Nice progress Craig. You’ll be knurling before the weekend is over…


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## YYCHM (Aug 19, 2022)

A bit of a fitment test reveals...






The swivel shoulder is a tad too wide.  I measured 0.026" above what the plans call for.  Need to do something about that before milling the top half off.

Had a bit of a shock when I discovered the knurling wheels fit rather loosely on the 1/4" tool steel wheel axle provided.  The wheel ID's look to measure 0.261" (6.63mm)

@Aliva did yours fit like that as well


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## RobinHood (Aug 19, 2022)

Make custom axles shaped just like your swivel; dimension them to fit the knurling wheels perfectly.


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## trlvn (Aug 20, 2022)

YYCHM said:


> Had a bit of a shock when I discovered the knurling wheels fit rather loosely on the 1/4" tool steel wheel axle provided. The wheel ID's look to measure 0.261" (6.63mm)


Have you checked with Doug Gray?  Maybe the wheels you got aren't quite up to snuff.

Craig
(Maybe we could entice him to drop in here from time to time?)


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## VicHobbyGuy (Aug 20, 2022)

trlvn said:


> Maybe the wheels you got aren't quite up to snuff.


Exactly- you don't want to re-size the axle to fit bad wheels.

How many sets of wheels are included with the kit?
You'll likely want several sets (different patterns and TPI)  eventually so having a tool that will accept off-the-shelf wheels will be important.
LMS wheels are $6USD a pair.
https://littlemachineshop.com/products/product_view.php?ProductID=2972
I just measured a couple of my LittleMachineShop knurler wheels - the bore is .252. Slightly wobbly fit on the axle, which is likely what I'd want...but not .010 oversize.
Axle is just under .250 - I just measured the end and it was .248.
BTW, The LMS wheels are .373 a.k.a. 3/8" wide.


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## YYCHM (Aug 20, 2022)

VicHobbyGuy said:


> Exactly- you don't want to re-size the axle to fit bad wheels.
> 
> How many sets of wheels are included with the kit?
> You'll likely want several sets (different patterns and TPI)  eventually so having a tool that will accept off-the-shelf wheels will be important.
> ...



I'm waiting for @Aliva to respond before contacting D. Gray.

I like dealing with LMS but don't like what they charge for shipping.  KBC sells knurling wheels as well.


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## VicHobbyGuy (Aug 20, 2022)

YYCHM said:


> I like dealing with LMS but don't like what they charge for shipping.  KBC sells knurling wheels as well.


I've bought several times from LMS. I agree the shipping is expensive. But, it seems to me (and I've done a bit of checking) that LMS is simply passing on the cost of shipping via USPS or courier.
KBC- 5x the price, plus excessive shipping costs.. Not an option for me.


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## YYCHM (Aug 20, 2022)

Swivels are done now....






Two swivels ready for a trim on the mill.






50% off the top and a little off the bottom.






One gets drilled through 5/16" the other threaded 5/16-24.  Sourced a real nice 5/16-24 tap from @Tom Kitta (Thanks Tom!).






Done and Done. Next up are two spacer pins...


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## PeterT (Aug 20, 2022)

Finely tuned counterweight I assume? LOL


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## Susquatch (Aug 20, 2022)

PeterT said:


> Finely tuned counterweight I assume? LOL



Hey @YYCHM!.... That doesn't look like a crappy tire tap to me!


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## YYCHM (Aug 20, 2022)

Susquatch said:


> Hey @YYCHM!.... That doesn't look like a crappy tire tap to me!



Na, that's an Osbom Blue Wizard HSS Spiral Point Tap I sourced from @Tom Kitta.  Tom figured it might be UK made.  Very nice.

@PeterT The cotter pin is for tightening/loosening the tap handle adjustment.  It binds a bit in places.  I usually remove it when tapping.


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## Susquatch (Aug 20, 2022)

YYCHM said:


> Na, that's an Osbom Blue Wizard HSS Spiral Point Tap I sourced from @Tom Kitta. Tom figured it might be UK made. Very nice.



I have a few of those blue wizards. They are nice.


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## Dusty (Aug 20, 2022)

PeterT said Finely tuned counterweight I assume? 

I thought it balanced the handle considering the speed in which Craig works.  Like the way the cotter pin is split nearer the bottom so that Craig won't loose it. LOL  Time for bed me thinks.


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## Susquatch (Aug 21, 2022)

YYCHM said:


> @PeterT The cotter pin is for tightening/loosening the tap handle adjustment. It binds a bit in places. I usually remove it when tapping.





Dusty said:


> I thought it balanced the handle considering the speed in which Craig works. Like the way the cotter pin is split nearer the bottom so that Craig won't loose it. LOL Time for bed me thinks.



This is really funny @YYCHM . Thanks for the laugh! Those F#&$@g things always stick and bind and come loose too.

I typically use a small punch or a junk Philips screwdriver. Most people throw them away after the tip gets mangled. My bride is a professional screwdriver tip mangler. I scoop them, grind the tip to a point like an awl (they are usually already pretty pointy) and then put them in a special drawer to be used for times like this and other tasks. 

I like your multipurpose cotter pin thingy dingy - balance, tool keeper, torque wrench (bends when proper torque is reached), aesthetic enhancer device......


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## Aliva (Aug 21, 2022)

YYCHM said:


> A bit of a fitment test reveals...
> 
> View attachment 25633
> 
> ...


Yes mine were also sloppy. I would have thought the fit should be tighter. I inadvertently ordered a metric kit so I attributed some of the clearance's  to metric imperial conversion.. I have other knurler wheels but the axel bore is too large  for the kits axel. I'd have to make a couple of stepped axels in order to use them , and I'd have to disassemble one side in order to fit the larger axel. I did purchase some 12mm HSS rod so I may do it in the future.


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## YYCHM (Aug 21, 2022)

Nothing too exciting today.....






Two spacer pins.






Pins are tapped 10-24.  Plans called for two bind holes but I drilled all the way through and tapped from one end.  I hate tapping blind holes.  @Dusty Note that my finely tuned speed balancer is removed  No tap casualties today






Turning the shoulders.






The pins fit the arm plates like so.


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## YYCHM (Aug 21, 2022)

Two wheel pins....






Nothing special here..... Just cut to length and add the two recesses.

Next up hinge pins.  Yuck... more tapping...

It's sad when you plan order of operations based on which you are most likely to sc.w up on


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## YYCHM (Aug 21, 2022)

Aliva said:


> Yes mine were also sloppy. I would have thought the fit should be tighter. I inadvertently ordered a metric kit so I attributed some of the clearance's  to metric imperial conversion.. I have other knurler wheels but the axel bore is too large  for the kits axel. I'd have to make a couple of stepped axels in order to use them , and I'd have to disassemble one side in order to fit the larger axel. I did purchase some 12mm HSS rod so I may do it in the future.



Did you glue your arm plates together in pairs and gang drill/ream them as one per the build notes?  Using my mill DRO on each plate, I ended up with one spacer pin hole that was out by a smidge and had to re-drill the two arms spacer pin holes as a pair.


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## DPittman (Aug 21, 2022)

YYCHM said:


> It's sad when you plan order of operations based on which you are most likely to sc.w up on


Hey that's how I work too!


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## VicHobbyGuy (Aug 21, 2022)

YYCHM said:


> It's sad when you plan order of operations based on which you are most likely to sc.w up on


That's not sad, it's smart. 
If you can do a higher risk operation before you invest a lot of time in machining, it makes sense to do it in that order. It certainly lowers my stress level to do things that way.


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## Dusty (Aug 22, 2022)

Craig said,  Did you glue your arm plates together in pairs and gang drill/ream them as one per the build notes? Using my mill DRO on each plate, I ended up with one spacer pin hole that was out by a smidge and had to re-drill the two arms spacer pin holes as a pair.

Most often a smidge becomes part and parcel of any project and doesn't interfere with the final outcome. Just saying!


----------



## Susquatch (Aug 22, 2022)

Dusty said:


> Most often a smidge becomes part and parcel of any project and doesn't interfere with the final outcome. Just saying!



Ain't that the truth! 




VicHobbyGuy said:


> That's not sad, it's smart.
> If you can do a higher risk operation before you invest a lot of time in machining, it makes sense to do it in that order. It certainly lowers my stress level to do things that way.



More truth! Been there, done that too! Feel exactly the same way! 

But it's still funny!


----------



## combustable herbage (Aug 22, 2022)

VicHobbyGuy said:


> That's not sad, it's smart.
> If you can do a higher risk operation before you invest a lot of time in machining, it makes sense to do it in that order. It certainly lowers my stress level to do things that way.


Stress???  This is too fun to be stressful, for me its not about the part I am making, its the journey of making it that is the fun part that's where I get the enjoyment so naturally I want to do the new/most difficult part first because it will bring the most reward and continue to build my skills.   I will when possible do a practice run on more difficult/unsure tasks to build confidence for a final usable product.


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## Aliva (Aug 22, 2022)

YYCHM said:


> Did you glue your arm plates together in pairs and gang drill/ream them as one per the build notes?  Using my mill DRO on each plate, I ended up with one spacer pin hole that was out by a smidge and had to re-drill the two arms spacer pin holes as a pair.


Yes I glued the arm plates together, but on one pair the glue let go when I was clamping it in the vise and this resulted in a small misalignment of the holes. A little filing took care of it. If I were to do it again I would put a small tack weld on the arms.


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## Susquatch (Aug 22, 2022)

Aliva said:


> Yes I glued the arm plates together, but on one pair the glue let go when I was clamping it in the vise and this resulted in a small misalignment of the holes. A little filing took care of it. If I were to do it again I would put a small tack weld on the arms.



Just wondering what kind of glue you used? 

I still can't weld worth crap. So I'm also wondering if a pair of sacrificial clamping screws wouldn't be just as effective. They could be removed when they are no longer required and the holes drilled out to become decorative weight reducing features.


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## StevSmar (Aug 22, 2022)

Looks like a great project! I’m looking forward to hearing what your opinion is on how it works.


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## StevSmar (Aug 22, 2022)

Aliva said:


> Yes I glued the arm plates together, but on one pair the glue let go…


I wonder if gluing the arm plates together, and then to a sacrificial aluminium plate would work. Then the arm plates could be clamped to the aluminium plate?

I’m very impressed with the way Joe Pie uses fixtures on his YouTube videos.


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## Aliva (Aug 22, 2022)

Susquatch said:


> Just wondering what kind of glue you used?
> 
> I still can't weld worth crap. So I'm also wondering if a pair of sacrificial clamping screws wouldn't be just as effective. They could be removed when they are no longer required and the holes drilled out to become decorative weight reducing features.


I used standard superglue. To release the glue just heat the parts with a propane torch. Use a wire buffer wheel to remove any residual glue


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## D. Gray Drafting & Design (Aug 22, 2022)

Thick superglue works well. Make sure the plates are well deburred and sit tight together. I sharp rap with a drift will separate the parts, (heat can cause nasty fumes).

Regards D.G.


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## Susquatch (Aug 22, 2022)

Aliva said:


> I used standard superglue. To release the glue just heat the parts with a propane torch. Use a wire buffer wheel to remove any residual glue



I'm not a fan of superglue. It requires a super tight fit. 

If I were doing it, I'd use epoxy which will also let go with a little heat.

Still leaning toward screws......


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## Susquatch (Aug 22, 2022)

StevSmar said:


> I’m very impressed with the way Joe Pie uses fixtures on his YouTube videos.



I generally like Joe Pie. Sometimes he can be a bit snotty, but he knows his stuff and so I can forgive him for it. Like most youtube authors, his videos are also too long.

Yes, he is a fixture wizard!


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## YYCHM (Aug 22, 2022)

Bloody Hell........






This 3/8" O1 tool steel hinge pin did my tap in  Doesn't look good for salvaging the hinge pin either.


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## jcdammeyer (Aug 22, 2022)

YYCHM said:


> Bloody Hell........
> 
> View attachment 25718
> 
> This 3/8" O1 tool steel hinge pin did my tap in  Doesn't look good for salvaging the hinge pin either.


Gawd I hate when that happens.


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## Degen (Aug 22, 2022)

Susquatch said:


> Just wondering what kind of glue you used?
> 
> I still can't weld worth crap. So I'm also wondering if a pair of sacrificial clamping screws wouldn't be just as effective. They could be removed when they are no longer required and the holes drilled out to become decorative weight reducing features.


Get a good TIG and you'll change your mind.


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## DPittman (Aug 22, 2022)

YYCHM said:


> Bloody Hell........
> 
> View attachment 25718
> 
> This 3/8" O1 tool steel hinge pin did my tap in  Doesn't look good for salvaging the hinge pin either.


Damn it!


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## Tom O (Aug 22, 2022)

I just did that in aluminum put a nut over it and weld it then give it a few wiggles to loosen it, it worked a charm for me.


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## VicHobbyGuy (Aug 22, 2022)

Tom O said:


> I just did that in aluminum put a nut over it and weld it then give it a few wiggles to loosen it, it worked a charm for me.


I've watched my neighbour do just that, several times, to extract broken taps and broken studs. It's like magic.


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## Dusty (Aug 22, 2022)

@Susquatch said 'More truth! Been there, done that too! Feel exactly the same way!

And I have the "T" shirt.  LOL


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## Dusty (Aug 22, 2022)

@YYCHM  Hey Craig time to put your tools down, step back, cool off with a hot supper and a good nights rest. 
Tomorrow's another beautiful day to take a positive look at things. Just saying!


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## Susquatch (Aug 22, 2022)

YYCHM said:


> Bloody Hell........
> 
> This 3/8" O1 tool steel hinge pin did my tap in  Doesn't look good for salvaging the hinge pin either.



Look up Walton Tap Extractor on Amazon. Pretty sure they would get this out without wrecking the part. For some reason I can't post a link today.

They have worked quite well for me over the years. Hardened fingers go down between the tap cutter edges and grip right at the break.

Better get another better tap from Peter too......


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## 6.5 Fan (Aug 22, 2022)

A nut and a welder works great.


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## VicHobbyGuy (Aug 22, 2022)

Susquatch said:


> Better get another better tap from Peter too......


And a #20 drill?


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## Susquatch (Aug 23, 2022)

VicHobbyGuy said:


> And a #20 drill?



This is a darn good point Vic.

@YYCHM - you should get a good threading chart or app. A good reference will list various drill sizes along with percent of thread that the drill provides.

Depending on the material and its machinability, and depending on how strong the joint needs to be, it is sometimes a significant advantage to pick a larger drill size in the chart to get less chance of breaking the tap. Here is a shot of the options for a 10-24 thread using a cutting tap on stainless or high strength steel.






This is from an app on my android. It allows me to choose my thread size, tap type, material, etc.

Keep in mind that the ideal optimum thread fit will always fail the screw first. As you increase the drill size, you move progressively closer to failing the hole threads instead. But there is a lot of room between the two. Also, the correct torque for the fastener is almost always way more than you need to achieve proper holding strength to keep the joint from coming loose. .


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## Susquatch (Aug 23, 2022)

@YYCHM - I found a link to my Walton Tap Extractor Set. It's expensive on Amazon but you get a good selection of the common sizes and they do work really well.

You can prolly find them cheaper elsewhere. 

I'm no darn good at welding so the nut and tack method doesn't work for me and won't work for anyone when the tap breaks off well below the surface.

Sometimes EDM is the only game in town. But I don't have EDM so I have to find someone who does.

The Walton Set has saved my bacon more often than not.

Walton Tools 18001 Tap Extractor Set https://a.co/d/84RDWHt


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## Dusty (Aug 23, 2022)

@Susquatch wrote The Walton Set has saved my bacon more often than not. Walton Tools 18001 Tap Extractor Set https://a.co/d/84RDWHt

Never used Walton broken tap extractors in fact I've never broken a tap which has to be by pure luck and drill bit selection. Reading the reviews from Amazon on this tap extractor set  https://a.co/d/84RDWHt leads me to believe they only work sometimes not always. Something to do with the extractor groves not being strong enough.

Could you expand further on your experience using same.


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## gerritv (Aug 23, 2022)

Can't remember the last time I broke one which I credit my approach 

I'll repost the charts from earlier in this thread. I print these out, slide into a plastic holder and keep in binder. All the charts that I use are in there so not faffing about remembering which app it was.
Broken taps are usually due to bending from not supporting the 'other' end (as in a a drill press/mill or tap guide), or esp. for smaller taps, hole size too tight of the metal. This is particularly important for small taps, as in anything smaller than M6 or 1/4".
Having metric drills from 1mm-6 in .1mm increments means I generally only have to look in one index instead of 3 to find a drill.
Lastly spiral point taps seem to be stronger, and don't require the tedious and bending prone quarter turn thing. I have taps from AliExpress, India, Butterfield, SKF and CTC.


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## Dusty (Aug 23, 2022)

@YYCHM  have my fingers and toes crossed that today will prove to be a better day for your tapping job. Stick with it my friend as I know you will.


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## Susquatch (Aug 23, 2022)

Dusty said:


> @Susquatch wrote The Walton Set has saved my bacon more often than not. Walton Tools 18001 Tap Extractor Set https://a.co/d/84RDWHt
> 
> Never used Walton broken tap extractors in fact I've never broken a tap which has to be by pure luck and drill bit selection. Reading the reviews from Amazon on this tap extractor set  https://a.co/d/84RDWHt leads me to believe they only work sometimes not always. Something to do with the extractor groves not being strong enough.
> 
> Could you expand further on your experience using same.



So let me begin by saying that I have FOUR sets of garbage taps.  Large and small Metric and Large and Small Imperial. Yah, you read that right, they are garbage.  They were all purchased in years gone by when I didn't know better. They cut crappy threads and they break easily.  But except for broken ones, they are complete sets of fine and course thread taps.  So they are SUPER CONVENIENT.  I wish they were not. Whenever I have to thread something I grab what I have and go for it. Inevitably I break them.  When I do, I don't cry about breaking the tap, I cry about losing my part!  I immediately go to Varco, my local jobber shop in Chatham, and I buy a good tap. Usually Dormer but I'm not fussy about the brand name as long as they are high quality taps.  

Then the problem begins - getting the broken tap out without losing the part.

Once upon a time I did that with needle nose pliers and tap extractors and a sharp awl.  Then a while back, a farmer friend loaned me his Walton set.  It was awesome.  So I bought my own set.  I have only once (that I can remember) failed to get the broken tap out. I bent the pins on the Walton with too much force, and that was that.  Dead in the water.  I ordered replacement parts and a week later tried again.  It worked that time.  Be gentle big fella.....

I have also used EDM at a local machine shop when the tap was too big for the Walton. EDM is awesome if you have access.

I think the secret to using the Walton tool is to make sure the collar is firmly against the work and then GENTLY wiggle the extractor back and forth - but mostly back - until the broken tap comes free. If you force it, it will bend and you are buying new ears.

I'd try welding if I could weld, but I cant. Certainly not on something so small. I don't have TIG. I have spent too much on welding gear already. 

I'd also like to say that I agree with other comments here - The secret to good tapping is a high quality tap and excellent alignment. When I can, I use my lathe or my mill or my drill press.  But that isn't always possible especially with farm equipment.  You can't put a set of disks on the mill.  The tap has to go to the work.  I have made a few fixtures to help keep things aligned, but that isn't always possible either. Farm repairs are hard work, on big parts, that cost a fortune.  The only way around it is to pay somebody else to totally mess it up for you and then buying a new machine.....


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## VicHobbyGuy (Aug 23, 2022)

gerritv said:


> Having metric drills from 1mm-6 in .1mm increments means I generally only have to look in one index instead of 3 to find a drill.


I have this set of metric drills and the quality seems pretty good.
https://www.banggood.com/Drillpro-5...etal-Drilling-p-1735296.html?cur_warehouse=CN

And my number/letter drill set is a basic 'Made in China' set. Probably similar to :
https://www.princessauto.com/en/327-pc-titanium-drill-bit-set/product/PA0008644734
or
https://www.princessauto.com/en/115-pc-titanium-drill-bit-set/product/PA0008721359
 Having options for 'just a little bigger hole' is really convenient. On the beginner model engine projects I've been trying, the difference between 'too much friction' and 'sloppy and wobbly' is slight. And, of course for tapping, too- getting the right size makes a big difference, with my hodge-podge of taps. The number/letter set fills in the gaps and takes over for larger sizes.


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## VicHobbyGuy (Aug 23, 2022)

For @YYCHM the good news is that a new piece of O1 should be fairly easy to source, and there's not much work invested in the part. If it were my project, I'd just make a replacement from 'mystery steel' from the scraps bin and keep pushing on, replacing that axle with O1 when I got it.
The knurler is designed to come apart for wheel swapping?


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## VicHobbyGuy (Aug 23, 2022)

Susquatch said:


> The secret to good tapping is a high quality tap and excellent alignment. When I can, I use my lathe or my mill or my drill press.


My new tap follower - Saturday afternoon's project- should help with this.  




For tapping into flat stock held in the vise, I have a few scrap metal blocks with holes for squaring up the tap.
I keep my taps and dies, separated by size- in Ziplock bags in a small bin. Masking tape label with drill sizes for 50%/75% . One bin for inch and NPT, the other for metric.


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## gerritv (Aug 23, 2022)

Susquatch said:


> The secret to good tapping is a high quality tap and excellent alignment.


And proper hole size.

For places where the tap goes to the workpiece I use tapping blocks. Has various tap close clearance holes, clamp block over hole, guides tap. I have one block for NC/NF and one for metric.


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## YYCHM (Aug 23, 2022)

VicHobbyGuy said:


> The knurler is designed to come apart for wheel swapping?



You can change wheels without disassembling it.  The wheel axles are held in place by two grub screws.


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## trlvn (Aug 23, 2022)

Susquatch said:


> ... So let me begin by saying that I have FOUR sets of garbage taps. Large and small Metric and Large and Small Imperial. Yah, you read that right, they are garbage. They were all purchased in years gone by when I didn't know better. They cut crappy threads and they break easily.


Bit of an aside, but...is it carbon steel taps that are most likely to break?

My impression is that cheap taps are generally made of high-carbon steel.  To be able to cut threads, the HC steel can't be tempered very much and is therefore still pretty brittle.  HC steel should cut just fine but a little bit of bending force, and...snap!

Or am I out to lunch?

Craig


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## Susquatch (Aug 23, 2022)

Dusty said:


> @YYCHM  have my fingers and toes crossed that today will prove to be a better day for your tapping job. Stick with it my friend as I know you will.



Could you please post a picture of all your toes crossed? 

A video of the process would also be helpful.


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## Susquatch (Aug 23, 2022)

trlvn said:


> Bit of an aside, but...is it carbon steel taps that are most likely to break?
> 
> My impression is that cheap taps are generally made of high-carbon steel.  To be able to cut threads, the HC steel can't be tempered very much and is therefore still pretty brittle.  HC steel should cut just fine but a little bit of bending force, and...snap!
> 
> ...



I believe my junk taps are all HSS. But I also have a few triple sets (regular, bottoming, and in between) that are made of mystery metal.


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## YYCHM (Aug 23, 2022)

This morning I sourced two new 10-24 taps and a pieced of SS to make a new hinge pin from @Tom Kitta (Thanks Tom!).






Man that 01 tool steel is horrible stuff to tap.  I ended up going up a drill bit size to 11/64.  Should have done that with the first pin when it was scritching with every turn of the tap

So one down now and one more to re-make.


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## Degen (Aug 23, 2022)

Fine center punch go, tap it out counter clockwise.  As soon as a the tap is exposed small visegrips, tighten on tight and turn out.

Not sharing how I know this method


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## Susquatch (Aug 23, 2022)

Degen said:


> Fine center punch go, tap it out counter clockwise.  As soon as a the tap is exposed small visegrips, tighten on tight and turn out.
> 
> Not sharing how I know this method



Ive done this in the past too.

Not ashamed to share past adventures.

Edit - Walton extractors are far superior. But sometimes ya just gotta use whatcha got......


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## DPittman (Aug 23, 2022)

I


YYCHM said:


> This morning I sourced two new 10-24 taps and a pieced of SS to make a new hinge pin from @Tom Kitta (Thanks Tom!).
> 
> View attachment 25762
> 
> ...


I'm not sure if this is relevant to your situation but #10 and 3/16" thread/screws are very close in size to each other,  and I believe are usually interchangeable but in hard material that may not be the case and might be the cause of problems.


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## Mcgyver (Aug 23, 2022)

Susquatch said:


> They have worked quite well for me over the years. Hardened fingers go down between the tap cutter edges and grip right at the break.


I must be doing something wrong, I've never had them work.  Not that I make a point of breaking taps, but it seems like they can never deliver enough torque to break the chip.  They're the Cone of Silence of my shop, great idea, never work like they're supposed to. 

I've have good luck drilling them out and also with my home brew EDM, but tap extractor success eludes me.  Probably something to do with the fact broken taps happening the in smaller sizes where there is not much space for the fingers.

Craig made the best call....not too much time into piece?  start over.


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## DPittman (Aug 23, 2022)

Mcgyver said:


> but tap extractor success eludes me. Probably something to do with the fact broken taps happening the in smaller sizes where there is not much space for the fingers.


I've had the same experience


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## RobinHood (Aug 23, 2022)

I have a set of Walton tap extractors. They seem to work as intended when required after a bozo move… fortunately, they collect dust in the tooling cabinet for much of their lives…

Last use was when I got overzealous power tapping Craig‘s mill table. Did not reverse the spindle before the tap reached the bottom of the blind hole - just shattered the thing. I recall Craig watching me getting the tap bits out using the Walton system.


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## Tom Kitta (Aug 23, 2022)

I just remove broken tap using old carbide EM. Drill it out. 

The SS supplied is not "soft" - its around the limit of what can one tap. So going up a drill size is natural.


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## YYCHM (Aug 23, 2022)

RobinHood said:


> Last use was when I got overzealous power tapping Craig‘s mill table. Did not reverse the spindle before the tap reached the bottom of the blind hole - just shattered the thing. I recall Craig watching me getting the tap bits out using the Walton system.



That was more my fault than yours I think.  I distracted you with a question at the crucial moment.  The extraction process was interesting.


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## YYCHM (Aug 23, 2022)

I cheated (for now) and used a 3/8" bolt shank for the replacement hinge pin.






Even that was a PITA to tap






First assembly.  Everything is nice and tight.  Maybe a little too tight?


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## Dusty (Aug 23, 2022)

@YYCHM said I cheated (for now) and used a 3/8" bolt shank for the replacement hinge pin. Even that was a PITA to tap.

Hey Craig I'm wondering if the answer for the hinge pin kit might be use drill rod of the correct diameter, tap that then harden same if needed. Sort of a wild guess on that. I've drilled and tapped drill rod on my lathe and mill although one must work gently with lots of lube.


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## YYCHM (Aug 23, 2022)

Dusty said:


> @YYCHM said I cheated (for now) and used a 3/8" bolt shank for the replacement hinge pin. Even that was a PITA to tap.
> 
> Hey Craig I'm wondering if the answer for the hinge pin kit might be use drill rod of the correct diameter, tap that then harden same if needed. Sort of a wild guess on that. I've drilled and tapped drill rod on my lathe and mill although one must work gently with lots of lube.



The hinge pins are drill rod. 01 tool steel drill rod.

@Dusty  Have you been power tapping on your lathe and mill?


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## Susquatch (Aug 23, 2022)

Mcgyver said:


> Not that I make a point of breaking taps, but it seems like they can never deliver enough torque to break the chip. They're the Cone of Silence of my shop, great idea, never work like they're supposed to.



Sometimes I read more into what others say than I should. This might be one of those times. I would never try to advance the tap to break the chip. I only break off the backward chip that has already been started when the tap broke. In that sense, nothing new is being cut, just whatever has started to lift from the trailing edge. 

I've never tried to examine what happens, but I'd expect that turning the tap backward only clears an already started chip. 

In any event, I never try to do that in one motion. I wiggle it backward and forward a smidge at a time. I don't force anything. In that way, the tap breaks the chip much like wiggling a piece of burr would break when you wiggle it back and forth. Sometimes it takes a lot of wiggling, but it's VERY satisfying when it finally turns back a full flute with virtually no effort. 

Perhaps it helps to visualize the process the way I do - it's like bending the started chip back and forth till it fails in fatigue. 

I will be honest, I have no idea where I got those instructions or even if I ever did get them from a source. They might well be the product of my own sick mind. 

What I can say for sure is that my garbage taps have given me lots of practice in recent years. I don't recall having early problems though. That would be back in the days of holding a drill bit and a tap up against a window to see how much the tap is cutting..... Back then, I prolly had much bigger holes than I use today! 

Ive now had a chance to check my tap sets. My oldest two sets (small metric and small imperial) are both HSS. My two big sets are both "Alloy Steel" but one is titanium coated and the other is tungsten coated. They are both that gold colour. I fully expect that the tungsten coating is an error and they are really titanium coated too. They are made in China.


----------



## Degen (Aug 23, 2022)

Susquatch said:


> Ive done this in the past too.
> 
> Not ashamed to share past adventures.
> 
> Edit - Walton extractors are far superior. But sometimes ya just gotta use whatcha got......


There are certain errors that evolved into very good learn experiences and discovery of new methods with limited tooling/time/options.

However, I going to not share those details as I never do those things.


----------



## Dusty (Aug 23, 2022)

YYCHM said:


> @Dusty Have you been power tapping on your lathe and mill?



The answer is no I've never done power tapping. All my tapping is done by hand supported with the correct sized drill bit, tap follower, lots of cutting fluid and soft hands.  One must be spot on with center punch and/or center drill or the job becomes fudged from the get go.  

When you are interrupted, tired, in a hurry, or muscle bound with tapping that's when Murphey's Law comes into the equation. Perhaps that's the main reason I've never broken a tap besides that my machine preference is my lathe or mill/drill over my drill press for total accuracy. 

Craig I like the quote button.


----------



## Susquatch (Aug 23, 2022)

Dusty said:


> The answer is no I've never done power tapping. All my tapping is done by hand supported with the correct sized drill bit, tap follower, lots of cutting fluid and soft hands.  One must be spot on with center punch and/or center drill or the job becomes fudged from the get go.
> 
> When you are interrupted, tired, in a hurry, or muscle bound with tapping that's when Murphey's Law comes into the equation. Perhaps that's the main reason I've never broken a tap besides that my machine preference is my lathe or mill/drill over my drill press for total accuracy.
> 
> Craig I like the quote button.



I like the quote button too. Did you know you can select some text and then get a choice to quote or reply as well? And that you can do this as often as you want? Nice feature! 

Back to the topic..... I'm jealous of your hands. Stuff of mine breaks no matter how gentle, or precise, or careful I try to be. My wife puts "FRAGILE" signs on inch thick solid steel around here.


----------



## YYCHM (Aug 23, 2022)

So... Tomorrow I plan to thread 2" of this 5/16 OD O1 drill rod...






I've already done one end and have the total thread DOC figured out.  The thread is usable but has a very rough finish.  I used an indexable carbide threading tool with 0.005 DOC per pass turning at 180 RPM and 0.01 thou (?) feed.

How do I eliminate the rough finish?


----------



## Susquatch (Aug 23, 2022)

YYCHM said:


> So... Tomorrow I plan to thread 2" of this 5/16 OD O1 drill rod...
> 
> View attachment 25784
> 
> ...



At that speed, I would have used HSS. But too late for that now. 

If you are confident in doing it, I might be tempted to pick up the existing thread with HSS and do a cleanup pass.  Or maybe be gentle with a wire wheel?


----------



## YYCHM (Aug 23, 2022)

Susquatch said:


> At that speed, I would have used HSS. But too late for that now.
> 
> If you are confident in doing it, I might be tempted to pick up the existing thread with HSS and do a cleanup pass.  Or maybe be gentle with a wire wheel?



So switch to HSS you figure?  I'm not worried about cleaning up the end thread, it's usable as is.


----------



## RobinHood (Aug 23, 2022)

O1 has a tendency to tear when threading on a manual lathe as the speed is usually too slow for the carbide tooling. It’s a bit better using sharp HSS.

One way to get a decent finish is to thread about 3/4 of the depth and then use a sharp threading die to finish it off. Some folks call that cheating, but it gets the job done with a decent result to show for.


----------



## Susquatch (Aug 23, 2022)

YYCHM said:


> So switch to HSS you figure?  I'm not worried about cleaning up the end thread, it's usable as is.



Ya, basically most standard carbide inserts are on the dull side and need speed to get good finish. Sharp HSS will cut well at lower speeds.

You could also try @dabblers trick of sharpening the carbide but I dunno about doing that on a threading insert.

You could also take a big swallow and go faster.

Do you have enough stock to try different scenarios?

Edit - I like @RobinHood s suggestion too. And I don't give a rat's butt about cheating. If it works it works!


----------



## historicalarms (Aug 24, 2022)

Dusty said:


> @Susquatch wrote The Walton Set has saved my bacon more often than not. Walton Tools 18001 Tap Extractor Set https://a.co/d/84RDWHt
> 
> Never used Walton broken tap extractors in fact I've never broken a tap which has to be by pure luck and drill bit selection. Reading the reviews from Amazon on this tap extractor set  https://a.co/d/84RDWHt leads me to believe they only work sometimes not always. Something to do with the extractor groves not being strong enough.
> 
> Could you expand further on your experience using same.


 Well....sure wish I had your "luck". I broke 3 taps yesterday alone....worst day I've had in the shop for a long time, broke those 3 taps & chipped a tooth on 2 new endmills. A good lesson here, at the first broken tap I should have walked away for a bit too let the dust clear (we'll call it "dust" anyways) but instead I did the "farmer thing" and "bulled ahead" until something else broke...the "dust" just got worse!!!


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## YYCHM (Aug 24, 2022)

A HSS threading tool and 250 RPM worked a little better......






Still as @RobinHood described it, the stock had a tendency to tear.  Multiple spring passes and a wire brush helped clean it up.

There wasn't enough room to deploy my follower rest


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## Darren (Aug 24, 2022)

pic of your threading tool, and compound angle? something seems off..


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## YYCHM (Aug 24, 2022)

Darren said:


> pic of your threading tool, and compound angle? something seems off..


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## Darren (Aug 24, 2022)

try setting the compound at 60 (30 away from 90). Thats your problem.

The tool looks to have the same issue. Do you have a fishtail gauge?


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## Darren (Aug 24, 2022)

Here is mine set to 29.5 degrees.


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## Darren (Aug 24, 2022)

Here's a proper 60 degree threading tool and a way to do a quick sanity check. Hopefully this helps.


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## YYCHM (Aug 24, 2022)

Darren said:


> try setting the compound at 60 (30 away from 90). Thats your problem.
> 
> The tool looks to have the same issue. Do you have a fishtail gauge?








Not perfect but close.  Note that mine has no top/back rake.


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## Susquatch (Aug 24, 2022)

Hey @YYCHM, it's an easy mistake to make. Those angles scribed on the compound are not relative to the work. They are relative to the cross slide. So you have to take the complementary angle. 

Frankly, I always thought it was stupid to be like that, but I don't design lathes. 

When I use my compound, I look at my work to see what the angles should be. Not the compound markings. Some guys even use an indicator and trig to set the angle correctly. 

The next problem is which way do you go to get 29.5 instead of 30.5.  Again, look at the work and it's easy to see which one will clean up the previous pass. 

The guys who plunge don't have this problem. But I'm not a plunger - at least not yet!


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## DPittman (Aug 24, 2022)

Darren said:


> try setting the compound at 60 (30 away from 90). Thats your problem.


The degree setting on the compound can be a confusing thing on some lathes.  On my lathe it has to read 60° to get actual 30°.  It all depends on where/how the start angle is.


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## jcdammeyer (Aug 24, 2022)

Totally agree with Darin.  On my South Bend the 0 degree mark is at the back and hard to see and with the scale on the back side even harder to set.  I had to hold my camera phone at arms length with front camera to get an image of the 29.5 degree setting.




From the side it looks like at some point someone scratched a line.  Or it's an accidental scratch.  Check your lathe to see if there is a 0 marking at the back.




I thought I had one of these for standard 30 degree threads but turns out I have two for ACME; came from KBC Tools.  Handy for setting up the tool bit angles and tip width if you want to cut ACME threads.


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## Susquatch (Aug 24, 2022)

historicalarms said:


> chipped a tooth on 2 new endmills.



You are supposed to bite the tailstock, not an endmill..... 

Ya, that old farmer thing is a powerful instinct. I think it's the weather's fault. Gotta get it done before the weather closes in. No time to stop and rest.


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## Darren (Aug 24, 2022)

YYCHM said:


> View attachment 25804
> 
> Not perfect but close.  Note that mine has no top/back rake.


A bit closer would help, and a bit of positive top rake would stop the tearing. Hone it on a stone after. The improvement will be quite noticeable


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## jcdammeyer (Aug 24, 2022)

Darren said:


> A bit closer would help, and a bit of positive top rake would stop the tearing. Hone it on a stone after. The improvement will be quite noticeable


Gee.  Mine never look that nice when I grind them.


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## Darren (Aug 24, 2022)

jcdammeyer said:


> Gee.  Mine never look that nice when I grind them.



Rough grind on the bench, tune up on the surface grinder. I use two grinding vices and angle blocks to set the compound angles.


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## jcdammeyer (Aug 24, 2022)

Darren said:


> Rough grind on the bench, tune up on the surface grinder. I use two grinding vices and angle blocks to set the compound angles.


Ah!  That's where I've been going wrong.  I've misplaced my surface grinder.


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## gerritv (Aug 24, 2022)

60dg tool (yours needs to be reground to be 60), ignore the compound angle stuff for 24tpi, it is pointless IMO and experience.

With A60 carbide insert I did this at 400 rpm in O1. 1/4-20 . The parts has M6 on one end, 1/4-20 on the other. Using an ELS so the shoulder isn't frightening, but you can see how SFM affects surface finish with crabide inserts on O1.


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## Tom O (Aug 24, 2022)

YYCHM said:


> View attachment 25804
> 
> Not perfect but close.  Note that mine has no top/back rake.


So what is that angle Wentworth is 55*


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## Darren (Aug 24, 2022)

gerritv said:


> 60dg tool (yours needs to be reground to be 60), ignore the compound angle stuff for 24tpi, it is pointless IMO and experience.
> 
> With A60 carbide insert I did this at 400 rpm in O1. 1/4-20 . The parts has M6 on one end, 1/4-20 on the other. Using an ELS so the shoulder isn't frightening, but you can see how SFM affects surface finish with crabide inserts on O1.



Yes with a properly ground tool or a carbide threading insert, you can ignore the compound angle....as long as you ONLY use the cross feed to move the tool, and never touch the dial on the compound. Infeeding with the compound however, does require the correct 29-29.5 angle to get a good thread.

Your threads look great. Do you have a post somewhere about your ELS?


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## gerritv (Aug 24, 2022)

No, I didn't post anyting about my ELS, mainly because I don't want to provide support for it. The code is from https://www.chipmaker.ru/topic/97701, comments are in Russian of course. ( I use the auto translate feature in MS Edge, it is good enough to get the gist with some fascinating phrases thrown in ) 
There is a close relative of the code and further details at https://github.com/kachurovskiy/megaels. He is using a slighlty older version than I am but both work.

OTOH I'll be happy to share how I mounted steppers on my KC1022/G0602/G0752 X and Z.

John D of course also has an excellent implementation.


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## gerritv (Aug 24, 2022)

Unlisted Video: 



 I'm more proficient with limit settings now to avoid the growling


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## jcdammeyer (Aug 24, 2022)

gerritv said:


> I'm more proficient with limit settings now to avoid the growling


Well if we're going to post videos here's one from 14 years ago using prototype #2.




Terrible camera and camera operation.  Once of these days I really should make a better one.


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## YYCHM (Aug 24, 2022)

One spring collar done.....






One to go.


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## Susquatch (Aug 24, 2022)

YYCHM said:


> One to go.



I admire you pluck. I'd have put it away for a few days despite my farming impatience.


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## YYCHM (Aug 24, 2022)

Two spring collars done now.....






But we have a problem.....






The 5/16 drilled bores won't slip over the unthreaded section of the tension rod.  The plans called for them to be reamed but I don't have that reamer nor propose to get one.  The walls of the narrow sections are too thin to re-drill one size up I figure.  May have to thin the unthreaded section of tension rod some how?






Man brass makes a sticky powdery mess.


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## gerritv (Aug 24, 2022)

I would chuck the threaded part in 3 jaw with a wrap of soft drink aluminum can as protection. Then file/emery/something the unthreaded portion to better fit the bushings.


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## D. Gray Drafting & Design (Aug 24, 2022)

I found the end of the threads leaves a bur. Chuck as Gerrit says and perhaps a pass with a fine file.


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## YYCHM (Aug 24, 2022)

Fixed....






I used the supplied nut in the 3J and took a skim pass across the unthreaded section of the tension rod.






Need to do some fine tuning now.  It's binding a bit.


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## D. Gray Drafting & Design (Aug 24, 2022)

looking good Craig!


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## PeterT (Aug 24, 2022)

@YYCHM  did you follow post #124 and re-make the part or...? I think he correctly identified that your compound was not set correctly based on you picture. That was my guess as well because the thread form looks off. If that's what you did then for sure you would have surface issues. But more importantly, its not really a proper thread form because of how the tool was advancing (which makes me wonder how it threaded on the nut). Anyways, ignore if I'm stating the obvious.


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## Susquatch (Aug 25, 2022)

PeterT said:


> @YYCHM  did you follow post #124 and re-make the part or...? I think he correctly identified that your compound was not set correctly based on you picture. That was my guess as well because the thread form looks off. If that's what you did then for sure you would have surface issues. But more importantly, its not really a proper thread form because of how the tool was advancing (which makes me wonder how it threaded on the nut). Anyways, ignore if I'm stating the obvious.



I'm with Peter on this @YYCHM. I'm guessing (and hoping) that you made a new part. But if you didn't, I'd highly recommend that you do.

I know, that will feel like a step backward, but just look at it as another opportunity to have fun and practice threading! 

Assuming you cut the first rod deep enough to get the nut on, that means that you also had to remove the crests because of the approach angle for the threading tool. That means the OD of the thread is significantly reduced and will easily strip in the future as you use the knurler and torque down the clamping nut on those weak threads. Basically, I think it will probably just work for a while and then fail in the middle of a future job. 

If you already made a new rod, then just tell me to stop being an old worry wart. 

BTW - it's really turning out to be a cool tool!


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## YYCHM (Aug 25, 2022)

PeterT said:


> @YYCHM  did you follow post #124 and re-make the part or...? I think he correctly identified that your compound was not set correctly based on you picture. That was my guess as well because the thread form looks off. If that's what you did then for sure you would have surface issues. But more importantly, its not really a proper thread form because of how the tool was advancing (which makes me wonder how it threaded on the nut). Anyways, ignore if I'm stating the obvious.





Susquatch said:


> I'm with Peter on this @YYCHM. I'm guessing (and hoping) that you made a new part. But if you didn't, I'd highly recommend that you do.
> 
> I know, that will feel like a step backward, but just look at it as another opportunity to have fun and practice threading!
> 
> ...



I'll be re-working the hinge pin and tension rod once I source some O1 drill rod.


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## VicHobbyGuy (Aug 25, 2022)

Susquatch said:


> and will easily strip in the future as you use the knurler and torque down the clamping nut on those weak threads. Basically, I think it will probably just work for a while and then fail in the middle of a future job.


It would be interesting to get some numbers on torque and axial pressure for the tension bolt in knurlers. That 5/16 tension rod in @YYCHM 's project is bigger than the one on my small knurler(s) - perhaps it would last a long while.
https://www.engineeringtoolbox.com/bolt-torque-load-calculator-d_2065.html
Re-making the part does seem like the best option to me (also) if for no other reason than 'job satisfaction'. I've found in the past that even though others might not notice mistakes in my projects, some of them can be a 'reminder' every time I use the item. Doing a test piece with ordinary CRS or 'mystery metal' while waiting for the O1 might make the work less stressful and get all the dimensions and measurements/settings sorted out.


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## VicHobbyGuy (Aug 25, 2022)

It's really interesting reading @YYCHM 's posts about the build of this kit. Thanks, @YYCHM !
It clearly points out the advantages and disadvantages of buying a kit of parts.
The big advantages IMO is that one saves the expense of buying more metal than really needed and avoids the hassle (and shipping expenses) of finding uncommon parts.
The downside is that there's not extra metal to remake parts if a problem crops up. For me, that increases the stress level - I re-make a lot of parts! Lots of "That's another learning experience"  
Whether my ever-increasing pile of metal stock - buying 'just some extra' for every project-  is a plus or not is another matter for discussion. No doubt the eventual executor of my estate will not share my happiness!


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## PeterT (Aug 25, 2022)

I'm trying to find some information I saved on O1, but cant seem to locate it. I seem to recall tensile strength (in annealed condition which is what you have) was not appreciably different than other more common grades of steel we use, but at lower cost & higher machineability rating. Unless you plan on heat treating it after threading, personally I don't see the sense of O1 in this case. You could make it from 4140 or 303 stainless. Even 12L14 which machines like a dream is about 78ksi UTS.


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## YYCHM (Aug 25, 2022)

PeterT said:


> I'm trying to find some information I saved on O1, but cant seem to locate it. I seem to recall tensile strength (in annealed condition which is what you have) was not appreciably different than other more common grades of steel we use, but at lower cost & higher machineability rating. Unless you plan on heat treating it after threading, personally I don't see the sense of O1 in this case. You could make it from 4140 or 303 stainless. Even 12L14 which machines like a dream is about 78ksi UTS.



All of my metal stock is essentially donated mystery metal, so to go with something other than O1 would still need to be sourced.


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## VicHobbyGuy (Aug 25, 2022)

PeterT said:


> Unless you plan on heat treating it after threading, personally I don't see the sense of O1 in this case.


As soon as I saw the meniton of O1 in this kit, I assumed that heat-treating would be one of the specified construction steps. If not, I don't see the point in specifying it. 12L14 is so nice to work with...definitely worth having some on hand,even if it means shopping at the local MetalSupermarket.  BTW, I have a lot of problems drilling stainless and had to re-make the barrel of my tap follower when the SS from my 'mystery box' couldn't be drilled...so I wouldn't recommend SS as a replacement! (SS= horrible stuff and not fun, for me).


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## YYCHM (Aug 25, 2022)

VicHobbyGuy said:


> so I wouldn't recommend SS as a replacement! (SS= horrible stuff and not fun, for me).



I had the same experience with SS, horrible stuff.  It work hardens as you turn/drill it.  Had a piece I planned to tap for a end cap screw (axle for a teeter totter).  Ended up drilling through and using a cotter pin.  Could not get it to tap.


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## thestelster (Aug 25, 2022)

Homedepot 1/2" x 6" hex head grade 8 bolt should do the trick.  About $7.  Grade 5= $5.15


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## gerritv (Aug 25, 2022)

I think 4140 and 303 love to work harden, i'm confident Craig doesn't want the additional fun of that.

For the threads, I'm not sure how ppl can determine that your overall diameter is wrong from a photo, a skill I don't have yet.
Outside of needing to touch up your cutting tool to be 60dg, it is worth noting that a thread has tolerances. So a 5/16-24 can be major diameter of 0.3125-0.3053 and still be a class 3A fit. A class 1A fit would be a range of 0.3114-0.3006 IOW quite a bit of leeway. I have found that the root width is the deciding factor on whether a nunt goes on or not. For most thread types that is .25 * pitch so for 24 tpi it is 0.078". I know we love to gring these cutters to a point but it is not really correct. The peaks also should not be sharp, again at .25 * tpi. This is actually one of the things to watch for with A/AG60 inserts, the range they claimis not supported by the tip width of the cutter. I always have to grind that for the higher pitch end of the cutter range.

Your tap should be labelled with its tolerance, the rest is in Machinery's Handbook since this is imperial stuff.

If my threading on the lathe is not smooth enough I use a Cratex stick, from coarse to fine to get the finish I need. For this adjuster I would say it should be smooth given the torque needed to get the knurl to form.


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## PeterT (Aug 25, 2022)

I haven't found 303 to be too bad, but I agree some of the other SS alloys are brutal. This was done at my lowest lathe speed with carbide insert - violating all the sacred rules! LOL
Threading results seem to vary by individual, so buy a few sticks of this & that & give it a whirl.
I also agree that bolts, threaded rod & the like can be a good source of decent quality metal stock for similar application small projects vs bar stock. I have found getting through the threads &/or coating can sometimes be interesting, but relatively smooth sailing once in the core.


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## thestelster (Aug 25, 2022)

thestelster said:


> Homedepot 1/2" x 6" hex head grade 8 bolt should do the trick. About $7. Grade 5= $5.15


Or if you really want strength, SHCS ( socket head cap screws).  But carbide inserts please!!


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## YYCHM (Aug 25, 2022)

Worked on the tension knob today....






After a whole bunch of mucking round (truing, drilling, tapping, thread a mandrel to hold it) I finally got to the point of knurling it.   It's not as crooked as the image depicts LOL.






Then I discovered the body tang is too wide for my tool holders, so it was off to the mill for a trim....






Finally got to point of knurling only to discover.... The whole tool is too long for my lathe @#@$%^#%%#&&((


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## gerritv (Aug 25, 2022)

Is that as far back as the cross slide will go (I'm sure it is but had to ask :-(


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## VicHobbyGuy (Aug 25, 2022)

Very unsatisfactory! Can Gray provide replacement plates or can you shorten the tool somehow? Can you fit the knurler into a lantern toolpost?


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## YYCHM (Aug 25, 2022)

gerritv said:


> Is that as far back as the cross slide will go (I'm sure it is but had to ask :-(



Yes


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## Susquatch (Aug 25, 2022)

thestelster said:


> Homedepot 1/2" x 6" hex head grade 8 bolt should do the trick.  About $7.  Grade 5= $5.15



Grade 5 is more than adequate and easy to machine. Bolts are cheap. That is what I would do too.



gerritv said:


> For the threads, I'm not sure how ppl can determine that your overall diameter is wrong from a photo, a skill I don't have yet.



Bear with me on this one @gerritv. It might be a rough ride.

This result is from geometry, not from looking at a photo.

In order for the nut to actually thread on, the thread root must be close to full depth. Perhaps a little less due to tolerances.

If the advancing tool follows a 60 degree slope (because of the compound setting) while cutting the thread, it takes a longer path to reach full thread depth. And therefore the trailing slope of each thread is also longer than it should be.

However, the advancing side of the cut is dictated by a form tool cut at the standard 30 degrees not by the compound angle. When the 60 degree cut reaches full depth (to allow the nut to go on) the 30 degree form cut removes about 1/4 of the top of the thread ahead of it. This reduces the diameter of the threaded shaft by about a quarter of the thread depth.






The overall effect should be a fairly clean leading edge on the thread from the form tool and a pretty ragged trailing edge from the combined form and compound angle.

My concern is that the nut will feel ok because the tip of the thread on the nut will engage and follow the root. But the nut will have no support on the 60 degree angle at all and the effective thread engagement will also be reduced by the smaller diameter. All in all, not a good outcome for something that sees very high tensile loads.

Feel free to challenge and/or ask questions. I take no offense especially since this is clearly not intuitive.

Too bad I don't have @PeterT's drawing skills!


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## StevSmar (Aug 25, 2022)

YYCHM said:


> Finally got to point of knurling only to discover.... The whole tool is too long for my lathe @#@$%^#%%#&&((


Oh no, you must be super dissapointed. All that work and it doesn’t fit.

Hope you’re able to find a solution.


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## gerritv (Aug 25, 2022)

I understand the drawings and likely what happened given the compound setting. It's interesting though in that the nut will act on the other side of the V (rh side) as it is tightened, the rod is being pulled, not pushed.
I am just saying that without measuring the actual thread result you can't tell from a photo. It could be that the incorrectly ground angle compensates and the end result is 'close enough'. Craig could have cut deeper and 'made up for it'. Also don't know what the tip of the tool really looks like. I can't tell from the photos. 

Actual full thread depth is .625 * pitch regardless of UN/UNC/UNF or even metric. Also known as major diameter-minor diameter. The theorectical point to point is .8663 * pitch but those tips are always/should be lopped off. All predicated on starting with the correct diameter work piece, which for 5/16-24 would likely be .3114, not .3125. This stuff is engrained in a (slowing) brain due to struggling matching threads internal and external on some old stuff. It was supposed to be BA but had 55dg angle  And other peculiarities. In the end had to grind internal and external custom tooling.


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## YYCHM (Aug 25, 2022)

Not one to give up.........






I lobbed off the back fillets on the body plate with the mill.  That bought me just enough room to move the tool back in the tool holder.






This is the tension knob knurled.  The tool created a nice crisp bold knurl in brass.  I discovered that you can torque down the knurling wheels to point of spinning the mandrel in the chuck






Tool installed in a tool holder with tension knob install  I think the real solution here is to shorten a tool holder 3/8" or 1/2" or so.


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## D. Gray Drafting & Design (Aug 25, 2022)

That's great news Craig. I was just about to PM you about some replacement plates. Now everything you see will need a knurl.


----------



## Chicken lights (Aug 25, 2022)

YYCHM said:


> Not one to give up.........
> 
> View attachment 25861
> 
> ...


Nice save!!


----------



## YYCHM (Aug 25, 2022)

D. Gray Drafting & Design said:


> That's great news Craig. I was just about to PM you about some replacement plates. Now everything you see will need a knurl.



Interesting.... Do you have shorter arm plates?


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## gerritv (Aug 25, 2022)

you're like a leech with lock jaw, nothing can make you let go of the goal  Congratulations!!!!


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## YYCHM (Aug 25, 2022)

gerritv said:


> you're like a leech with lock jaw, nothing can make you let go of the goal  Congratulations!!!!



LOL... Badger maybe,  Leech no.  Wife calls it being Tenacious.


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## Susquatch (Aug 25, 2022)

gerritv said:


> I understand the drawings and likely what happened given the compound setting. It's interesting though in that the nut will act on the other side of the V (rh side) as it is tightened, the rod is being pulled, not pushed.
> I am just saying that without measuring the actual thread result you can't tell from a photo. It could be that the incorrectly ground angle compensates and the end result is 'close enough'. Craig could have cut deeper and 'made up for it'. Also don't know what the tip of the tool really looks like. I can't tell from the photos.
> 
> Actual full thread depth is .625 * pitch regardless of UN/UNC/UNF or even metric. Also known as major diameter-minor diameter. The theorectical point to point is .8663 * pitch but those tips are always/should be lopped off. All predicated on starting with the correct diameter work piece, which for 5/16-24 would likely be .3114, not .3125. This stuff is engrained in a (slowing) brain due to struggling matching threads internal and external on some old stuff. It was supposed to be BA but had 55dg angle  And other peculiarities. In the end had to grind internal and external custom tooling.



I'm thrilled that you were able to follow what I was describing. 

And yes, I agree that for this instance and the way the rod was held and fits the assembly, the nut will bear on the better left 30 degree slope. 

But as per my first note, my real concern is the reduced effective diameter. 

Looks like Craig (@YYCHM) was able to slip the part being knurled in the chuck though, so perhaps it's still plenty enough. And he does plan to make a proper tensioner bolt down the road so I'm just gunna drop it for now. If he ever strips the rod in future, we will know why.


----------



## Susquatch (Aug 25, 2022)

YYCHM said:


> Interesting.... Do you have shorter arm plates?



And another tentioning rod.....


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## YYCHM (Aug 25, 2022)

Susquatch said:


> And another tentioning rod.....



Well if your going to go that far.... and another hinge pin as well LOL.


----------



## PeterT (Aug 25, 2022)

Susquatch said:


> This result is from geometry, not from looking at a photo.
> In order for the nut to actually thread on, the thread root must be close to full depth. Perhaps a little less due to tolerances.
> If the advancing tool follows a 60 degree slope (because of the compound setting) while cutting the thread, it takes a longer path to reach full thread depth. And therefore the trailing slope of each thread is also longer than it should be.
> However, the advancing side of the cut is dictated by a form tool cut at the standard 30 degrees not by the compound angle. When the 60 degree cut reaches full depth (to allow the nut to go on) the 30 degree form cut removes about 1/4 of the top of the thread ahead of it. This reduces the diameter of the threaded shaft by about a quarter of the thread depth.
> ...



I agree. That's what we are looking at - the telltale thread form, not the diameter. 

I had to think about this a bit sketch wise. Not sure I have it right but here goes. First pic shows the compound set at 30-deg. I advanced the 60-deg tool in 3 equal increments of (arbitrary) 0.020". Orange shows the net result, a typical 60-deg V thread to full depth. Second pic shows compound set at oops 60 deg & infeeding same equal compound advancement. Result is raggedy trailing edge as @Susquatch says and OK looking leading edge. The actual sawtooth shape will be dictated by whatever sequence of infeeds actually occurred. The other telltale sign should have been the cookbook DOC should result in a shallower male thread pitch diameter & should not have fit. That's why when I saw the nut threaded on I was a bit mystified. Maybe you kept going till it went on? (And yes, I have made this exact mistake myself.)


----------



## YYCHM (Aug 25, 2022)

@gerritv , @Susquatch the major dia of the tension rod ended up being 0.303" if that sheds some light on the situation.


----------



## PeterT (Aug 25, 2022)

Hmmm, maybe I have this wrong. If after each DOC thread pass, the tool is retracted out by cross slide, return to start of thread, zeroed to same position (1) then infeed next DOC increment with compound only, then the trailing edge should be the wrong (shallow) angle but more reasonably smooth, not sawtoothy like I drew before.


----------



## Susquatch (Aug 25, 2022)

YYCHM said:


> @gerritv , @Susquatch the major dia of the tension rod ended up being 0.303" if that sheds some light on the situation.



What was it before threading?


----------



## YYCHM (Aug 25, 2022)

Susquatch said:


> What was it before threading?



After.  The drill rod was 5/16 so 0.3125 before.


----------



## Darren (Aug 25, 2022)

PeterT said:


> Hmmm, maybe I have this wrong. If after each DOC thread pass, the tool is retracted out by cross slide, return to start of thread, zeroed to same position (1) then infeed next DOC increment with compound only, then the trailing edge should be the wrong (shallow) angle but more reasonably smooth, not sawtoothy like I drew before.


 Thats what I saw when I zoomed in, and could see something wasn't right. 

I've made the same mistake. Its easy enough to do.  I did it making a backplate with internal 1.5"/8tpi threads. I caught it early though. 

Also, my Emco has radius dials, where my SM has diameter dials. Screwed up a ribbed pulley by moving the tool over for the next rib by half the required distance.  Shit happens.


----------



## Susquatch (Aug 25, 2022)

PeterT said:


> Hmmm, maybe I have this wrong. If after each DOC thread pass, the tool is retracted out by cross slide, return to start of thread, zeroed to same position (1) then infeed next DOC increment with compound only, then the trailing edge should be the wrong (shallow) angle but more reasonably smooth, not sawtoothy like I drew before.



I think your first drawing is correct. Cross slide only sets a consistent reference point. Compound advances the cut. The cut itself is made by the firm tool which owing to the 60 degree advance does not fully clean up the previous pass. So I think it will be a saw tooth cut. 

But that's what I see in my mind without standing at the lathe or having the benefit of your amazing drawing skills. Regardless, the right side of the cut will be too shallow and too long, and the left will lopp off some diameter. 

Ive said it at least a dozen times now. I really am jealous of how easily and quickly you whip off drawings to support what you say.


----------



## Susquatch (Aug 25, 2022)

YYCHM said:


> After.  The drill rod was 5/16 so 0.3125 before.



Well, it supports the theory, the thread depth should be around 24 thou so you have lost about a 1/4 of the thread diameter just about as predicted with a swag.


----------



## Susquatch (Aug 25, 2022)

Darren said:


> Also, my Emco has radius dials, where my SM has diameter dials.



That would drive me bonkers..... 

I can't wait to install a DRO on my lathe too and leave all that crap behind me.


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## RobinHood (Aug 25, 2022)

Good that you were able to make it work (with some mods) Craig.

You’d have to confirm, but I think your compound would swing past the 0* position (ie aligned with the longitudinal axis of the lathe) by some amount. If you did that and then extended the compound, you would gain distance away from the work. All you then need to do is turn the tool post around so the your knurling tool aligns. No need to shorten up a tool holder.

This does reduce the rigidity a bit as the compound is now extended a bit (you mention a requirement for about a 1/2”).

Also, this only works if the TS is not being used to support the work.


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## Susquatch (Aug 25, 2022)

PeterT said:


> Hmmm, maybe I have this wrong. If after each DOC thread pass, the tool is retracted out by cross slide, return to start of thread, zeroed to same position (1) then infeed next DOC increment with compound only, then the trailing edge should be the wrong (shallow) angle but more reasonably smooth, not sawtoothy like I drew before.



Your second drawing is actually correct, and so is your first description. But I think you mixed them up. Here is the saw tooth. The parts I scribbled on  don't get cleaned up by the bit. Of course it wouldn't be that bad because there would be more passes. And of course you still have the longer advance and the lopped off diameter.


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## Darren (Aug 25, 2022)

It forms a sort of buttress thread.


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## YYCHM (Aug 25, 2022)

This is the bolt shank mandrel I threaded with the compound set correctly.....






The total DOC was closer to what I expected.  I used a carbide threading tool at 250 RPM.  The thread finish isn't great, but better.


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## Susquatch (Aug 25, 2022)

Susquatch said:


> And of course you still have the longer advance and the lopped off diameter.


@PeterT - You would have to superimpose a proper 30 degree thread to see how the diameter gets lopped off. 

Anyway, much as I love theoretical discussions like this, they are really all moot at this point. The rod held for now and @YYCHM will be making a new one.


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## Susquatch (Aug 25, 2022)

YYCHM said:


> This is the bolt shank mandrel I threaded with the compound set correctly.....
> 
> View attachment 25868
> 
> The total DOC was closer to what I expected.  I used a carbide threading tool at 250 RPM.  The thread finish isn't great, but better.



Perfect! We all knew you could do it! It's that badger in you!


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## PeterT (Aug 25, 2022)

Ah yes. Because you are advancing the tool for the next pass while still outside the thread zone, then engaging the threading lever at that new DOC. So its making a new cut like the next larger triangle to the left & the in-between area still remains sawtoothy.


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## Susquatch (Aug 25, 2022)

PeterT said:


> Ah yes.



Yup! And @YYCHM confirms the diameter loss. 

But it still works!!! Amazing!


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## gerritv (Aug 25, 2022)

YYCHM said:


> @gerritv , @Susquatch the major dia of the tension rod ended up being 0.303" if that sheds some light on the situation.


that is still within the spec for 1A tolerance on 5/16-24 thread. But it is certainly on the loose end of the fit spectrum.

A typical outside diameter of the finished thread would be .3114, Anyway at this point weI am beating this to death, glad you now have a good adjuster rod, and a knurled nut. Because as said earlier, now everything needs a knurl!


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## DPittman (Aug 25, 2022)

Susquatch said:


> That would drive me bonkers.....
> 
> I can't wait to install a DRO on my lathe too and leave all that crap behind me.


Says the guy that doesn't trust digital readouts!


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## Susquatch (Aug 25, 2022)

DPittman said:


> Says the guy that doesn't trust digital readouts!



I suppose I could try to justify an exception, but I'd prolly just end up sounding half my age.

So ya, I deserved that. 

You made me laugh out loud though!


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## YYCHM (Aug 26, 2022)

Sacrificed a tool holder today.....






This is what a 2" piece of round stock looks like with an unmodified tool holder.   Just makes it with the cross slide all the way back.






The same stock with the shortened tool holder.  Have some wiggle room now.






The shortened tool holder.  Should be OK I think.


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## gerritv (Aug 26, 2022)

Looks like the height nut on the tool holder needs a new knurl now


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## YYCHM (Aug 26, 2022)

Just for comparison....






The D Grey knurler

An AXA bump knurler

And a mini-lathe size BB scissor knuler

Time to move on to a new project which incidentally has been spawned by doing this project LOL.


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## PeterT (Aug 26, 2022)

What!!? Its tradition to end a build post with an example - some perfect diamond knurls on a part of your choice!


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## YYCHM (Aug 26, 2022)

PeterT said:


> What!!? Its tradition to end a build post with an example - some perfect diamond knurls on a part of your choice!


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## PeterT (Aug 26, 2022)

Ah, sorry, I missed that detail. <open gate> You May Pass lol


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## Dusty (Aug 26, 2022)

Hey Craig, dedicating a tool holder to a specific tool meaning knurler is very wise. I don't see how sacrifice fits in. Well done old timer!


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## StevSmar (Aug 26, 2022)

gerritv said:


> Looks like the height nut on the tool holder needs a new knurl now


I agree, now that the tool holder and knurling tool are forever together, it’s only right that they sport the same knurl.

Well done @YYCHM , glad you were able to successfully complete your project!


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## VicHobbyGuy (Aug 26, 2022)

YYCHM said:


> Just for comparison....
> 
> The D Grey knurler
> 
> ...


Very nice job on the project! 
Looks like a very sturdy tool. Attention all metals: "Resistance is futile!" 
It's interesting that everything on the Grey knurler is 'supersize' except the tension knob.


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## YYCHM (Aug 27, 2022)

Congratulations to Mr. C. of Calgary Alberta Canada
					

Congratulations to Mr. C. of Calgary.  Mr. C. recently completed his Heavy Duty Knurling Tool kit. Mr. C. had a few trials and tribulations (broken tap) but persevered and now has a tool he can be proud to point to and say "I made that".  One issue Mr. C. run into was that he found the tool was...




					www.hobby-machinist.com


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