Former Member
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Not clouded, keeping an open mind doing the research. Remember I am an engineer too and develop my own products and tooling and machinery. When things don't add up correctly question until you've exhausted it.
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Tool My most hated tool
- Thread starter ducdon
- Start date
Tool
Former Member
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Thanks @gerritv you just made my case. In an earlier post I mention the trick of an old machinist of skewing the knurling tool for easier cuts. In effect yes there is some cutting action happening as the edge or point of the tool contacts first. However more importantly the removal is just enough to cause reduced displacement of material and still causing work hardening (part of the desire effect). This by definition is "Knurling".The same way a lathe cutting tools works, it cuts at the point of contact. You will have seen that this photo is part of aligning the tool, this particular photo is of getting the angle correct. The wheel never cuts along its full width, only the left tip. The wheel must be at an angle (usally 30dg) for this to work.
The operation always starts at the end of the work piece (or a step if knurling in mid of some length). 1mm or so wide, crank in 0.5 of pitch and then feeed slowly axially. With the wheel (and thus tips) at an angle, it cuts as you move along.
I suggest you either model this in Fusion360 or make one. Even better, do both. Like the Euraka relieving tool, this is easier to understand when you see it in operation than it is to explain in words. If you make one, get the proper wheels, Quick/Zeus/Accu-Trak/Dorian etc. all make cut wheels. You will notice that these are narrow, since they cut only at the leading tips.
I will start a thread when mine arrive and I have the tool built. Single wheel only for RAA pattern
Gerrit
If it is true cutting to achieve the pattern by definition it is no longer knurling, just a mimic result without the hardened benefits.
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I found this design after rediscovering Rick Sparber's site from another post.
The knurling is done in the middle of the tool and the adjustment is at the end opposite of most designs posted.
The knurling is done in the middle of the tool and the adjustment is at the end opposite of most designs posted.
gerritv
Gerrit
I don't think I made your case but whatever you want to read into my writing is fine by me. I can assure you that cut knurling on 1mm wall aluminum tubing does not involve work hardening as it is essentially irrelvant on that material nor a requirement. Cut knurling is very prevalent in the optics industry, hence the plethora of Swarovski Optical patents.
I'm going to leave one more fact from Accu-Trak: (https://accu-trak.com/knurl-holders/cut-type-knurling.html) Implicit in their statement is that you are unlikely to find relevant facts in North American machining literature.
I've moved on to making the tool. I'll be back in a week or so when it is operational.
Out.
Gerrit
I'm going to leave one more fact from Accu-Trak: (https://accu-trak.com/knurl-holders/cut-type-knurling.html) Implicit in their statement is that you are unlikely to find relevant facts in North American machining literature.
I've moved on to making the tool. I'll be back in a week or so when it is operational.
Out.
Gerrit
That does not sound open minded to me. I'm thinking perhaps we have fundamentally different opinions of what it does mean. To me it means a mind that is not latched onto a particular view or trying to prove points. It is a mind that let's go of their convictions and beliefs and willingly considers other alternatives. In this case, in the hope of learning something new or different.
But that's ok. We can agree to disagree on what it means or even if it is necessary to be that way. We can also agree to disagree on everything else about cut vs pressure knurling.
Unfortunately, I think it also means I am probably not going to be much help to you on this one.
Former Member
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Gotta say you are funny on your views on occasion and how you call on only what suits your view.
Maybe others may know something beyond what you see.......
Hey @ducdon, is there not a hole at the bottom of the tool post that you can pin it to the compound slide? The tool post should not move under any circumstances. Also, check that the bottom of the tool post is perfectly flat in relation to the compound top surface.
Good catch @thestelster. We have been talking Knurlers, but that clamping arrangement that @ducdon uses should not be necessary.
Mine does not have a pin or a hole like you describe. But every other lathe I have looked at does. However my tool post has never moved with anything I have ever done. I have never even had to gronk on the retaining top nut - just snug and go.
Occasionally, I get the feeling that something held in the holder (eg a cutoff blade) isn't as rigid as it could be, but the BXA tool post itself has never moved.
Instead, my compound has a BIG T-slot in it, and the bolt for the BXA Tool Post threads into a huge plate that fits into the T-slot and acts like a giant T-Nut that is much bigger than what I have seen on other lathes.
Because my T-Nut can slide in the T-slot, I can't see how an anti-rotation pin could work. But it hasn't been necessary.
My lathe came with one of the same double ended combination style tool holders that @ducdon has. Mine doesn't rotate the tool post, but I don't hate mine any less than he hates his. It's just a hateful knurler period.
I like the scissor style much better.
Nonetheless, this thread has been a God send to me. Thanks to what I learned on here, there is now a cutting knurler in my future even if I have to make it.
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I know that the Dorian and Multifix have anti-rotation provisions, that get pinned by one or two dowels into the t-nut, or the compound slide.
Former Member
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@ducdon while a few of us have wasted a few pages re cut and pressure knurling theory and application (and likely still ongoing) I must agree that my lathes don't have have locking pins for the tool posts and never have had any issues with tool post rotation (unless I did something really stupid). This includes that lantern type holders, home made multi position holders and newest AXA holder set ups.
If you are doing pressure Knurling (without fancy tools) consider skewing your cutter slightly, this causes higher concentration of pressure while easing load on the post. (Similar to cut knurling theory, ha ha ha, had to get that in).
If you are doing pressure Knurling (without fancy tools) consider skewing your cutter slightly, this causes higher concentration of pressure while easing load on the post. (Similar to cut knurling theory, ha ha ha, had to get that in).
Chicken lights
Forum Pony Express Driver
You should ask them a question about oil some time....
You should ask them a question about oil some time....
To be totally honest about it, this is one of the things I like about CHMW. You never know when you are gunna learn something new and very different from what you thought you knew or even never heard of before.
For me, it beats the holy crap out of watching dumb YouTube videos! Not only that but previous CHMW issues are as simple as a quick search on anything!
Agreed. I didn't realize my tool frustration would become so profound a topic. I didn't see it coming and frankly was a bit overwhelmed as to when to jump back in.
I have been following along and decided what I will try and do.
@Mcgyver. Your cut knurl tool is great work. I think a bit beyond what I can justify in time for the bit of knurling I do.
The tool post is not pinned and I don't think that would work with the XA style post as I often rotate it to align HSS and brazed carbide tools.
Someone asked if I had checked the top and bottom surfaces of the tool post for parallelism. I have not and I will check into that for sure.
I did make a much more substantial T nut and bolt, but it didn't help. I will also order some new knurls. Maybe their just dull?.
I will also add a scissor type to my project to do list.
Thanks All.
@ducdon , you said you made a new, beefier T-Nut. I wonder if now you are actually bending the T-slot in the compound and are actually reducing the contact area compared to before?
I had the tool post rotate on the SM1340. For the life of me could not figure out why until I started checking things out. One was the bolt torque. Lower torque meant better contact and less likely to turn. I ended up surface grinding both the top of the compound and the bottom of the tool post. Then I used a piece of paper between them, and reduced the torque. Never slipped again, even under the heaviest of cuts.
Dickson style tool posts have a factory anti-rotation (locating) pin. Both the Colchester and the CMT lathe have corresponding locating holes in the compound. Must be a European thing?
I had the tool post rotate on the SM1340. For the life of me could not figure out why until I started checking things out. One was the bolt torque. Lower torque meant better contact and less likely to turn. I ended up surface grinding both the top of the compound and the bottom of the tool post. Then I used a piece of paper between them, and reduced the torque. Never slipped again, even under the heaviest of cuts.
Dickson style tool posts have a factory anti-rotation (locating) pin. Both the Colchester and the CMT lathe have corresponding locating holes in the compound. Must be a European thing?
gerritv
Gerrit
One thing to try with your bump style knurler is to only wind the cross slide in 0.4 of the pitch. There is no point going in deeper.
The knurl does look on the dull side but not sure that matters on form knurls.
Run a flat stone over the bottom of the QCTP and top of the cross slide, it doesn't take much to have a problem.
Create a chamfer at start of knurl. Wind in the crosslide quickly to the depth you need, then start axial movement.
There are more hints here: https://accu-trak.com/knurling-tips (for form knurls, not the other type
Further setup, speeds, feeds etc. from Quick on form knurling, with a tool similar to yours (but significant more costly) https://www.hommel-keller.de/wp-content/uploads/2021/09/OM_quick_F711_F712_EN_final-1.pdf
Gerrit
The knurl does look on the dull side but not sure that matters on form knurls.
Run a flat stone over the bottom of the QCTP and top of the cross slide, it doesn't take much to have a problem.
Create a chamfer at start of knurl. Wind in the crosslide quickly to the depth you need, then start axial movement.
There are more hints here: https://accu-trak.com/knurling-tips (for form knurls, not the other type
Further setup, speeds, feeds etc. from Quick on form knurling, with a tool similar to yours (but significant more costly) https://www.hommel-keller.de/wp-content/uploads/2021/09/OM_quick_F711_F712_EN_final-1.pdf
Gerrit
How did you get that across the border?
Ordered it thru Amazon.CA
Wow! Amazon won't always do that with Chemicals coming from the US for me. But sometimes they do.
Brownells will ship parts and things but NEVER chemicals of any kind. I assumed you bought direct from Brownells, hence my question.
All-in-all totally AWESOME that Amazon is working with Brownells. I wonder what they all carry?
I wish they would get with Midway. Midway refuses to deal with Canadians period. Customers with Canadian email addresses are regularly purged from their Customer data base.
Earlier you said the bluing was blotchy and you thought that might be from previous applications of other products. Have. You had the chance to test that yet?
The reason I ask is that your photos show a very rich dark bluing. I like that, but I have not been very successful with other cold bluing products to date.