Restoration/Repairs on a 10" LD Utilathe - Standard Modern

[Brent H]

There is one odd ball gear.......... well 2. One is a bronze gear (part 11 on feed gear train assembly): 12 tooth tumbler gear and part 16: 60 tooth Feed gear.

On the 1120/1336 drawings these show a DP of 17.37. I would assume the change in DP is to get the spacing correct and the contact angle would remain at 14.5 (it is not shown but all other gearing for the same function is 14.5 degrees)?

The gearbox gears (9 of them) are shown as 14 DP and a 20 deg pressure angle.......not sure how that will affect Johnwa if things are now meshing properly.

For the most part the gears all seem to fall into the 4 cutters 12 DP 20 PA, 14 DP 20 PA, 16 DP 14.5 PA and 16 DP 20 PA with one odd ball 17.37 DP for 2 gears - this one I will measure a bunch to see if it is correct when the time comes.

I will soon order up the cutters and see what I can do. First major event, however, will be line boring the tailstock and fitting a new shaft......that should be interestingly fun

 

[Johnwa]

Brian
Do you have a source for the drawings with gear specs. The manual I have just gives the number of teeth. I’ve also never been able to source drawings of my gearbox. The ones I got from LeBlond are slightly different.

 

[Brent H]

Hi Johnwa, here is the link: The drawings

You will need to look about the drawings for the gear specs, such as trace the gearing back to the first gear in the train and it will typically yield the DP, and PA

 

[Johnwa]

Thanks Brent
It does look like they should be 20PA.
I tried to measure the PA of the gears directly but for those gears the differences were down in my measurement error range.

 

[Brent H]

A small update:

While doing some other lathe work I noticed I was spraying oil and shavings off into the distance. I fabbed up a lathe shield out of some stainless sheet that was handy. I riveted most of the joints to maintain the stainless and used a cardboard template to shape the plate next to the lathe headstock. I added a wee shelf on top to hold some tools and keep things handy.





Should keep things a lot nicer and help protect the motor from sucking in metal swarf.

 

[historicalarms]

Some time ago I built a shelf that attached to the top of the splash guard that was already on the lathe, flat with no side ledge same as yours but I soon found out that even a slight vibration from machine rotation or more robustly from any "interrupted" cut type of thing, walked things around and over the edge so soon found out that a ledge was "compulsory".

 

[Brent H]

I am drilling in holes for all the chuck keys and centers/drills etc and the cutter holders will all have pins to keep things in place.

I hear you on the shelf ledge as I work on a ship - always making things to prevent vibration and heavy sea dumping

Brent

 

[Brent H]

ACME threading - such fun.....

So it was a bit rainy and no paint was going on the house (like I need an excuse ) and I decided to make a new compound feed nut for the lathe. This represented a challenge as I needed the lathe to make the nut and I don’t have any 1/2” - 10 RH acme stock for test fits. A G2 fit for an Acme 1/2 - 10 is a root diameter max of .380 and the depth of cut is .060. There is not a lot of room to run a boring bar with a proper shaped acme cutter - it was more a job than expected. First 2 attempts failed. On the second try I realized my little bit arrangement was too flimsy and was bending enough to not make the thread cut any deeper than about 30 thou. The bend also seemed to make the thread a bit angled.

I purchased a couple small (Busy Bee) boring bars with the straight and 45° cutter mount places. The small one takes 1/8” square bits.

The third attempt went well and the nut fits snug - however, there is thread wear on the ACME screw so that may prove to be another project.

The reason to re-make the nut was the back lash. It was about 0.025” and then add the same for the cross feed and it was a bit crazy. With the new nut I have about 0.005” of backlash on the compound. I am setting up for the cross feed nut and it is a 9/16 - 8 LH thread.

The threading set up:


The dial indicator was used to make sure I went in 0.060”

Test fit:



New “nut” in place:


Getting set to mill up the blank for the cross feed nut:



Will see how this goes.....

 

[PeterT]

Nice work. So you hand ground a HSS cutter to the ACME thread profile & that was held in the boring bar holder? Did you do it by eye & then held to the lead screw under magnification or somehow jig with a protractor on the grinder? I've always wondered how to gauge the accuracy of the profile on those bigger or less conventional threads.

Is the new nut brass or bronze?

 

[Brent H]

Hi Peter,

I ground up a cutter from 1/8”x1/8” hss just by “eye” but by “eye” I mean using an ACME thread gauge:


The “V” helps you set the 29° and the notches are the tip width. The open angle by the hole will help set the bit parallel to the work, however, in a boring bar for internal threads, it is important to grind the cutter evenly so that when you set up the bar parallel to the bore the cutter is running true.

The 10 TPI ACME is the smallest and man, it was hard to get the glasses focused. Here are some pic’s of the bit:

Top view:

Front view:



Bottom view:


The material, hmmmmm, My first attempt I milled out a blank from a piece of 1-1/2” brass round stock (similar to the hunk of brass going for the cross feed screw) but, after the fail I turned a piece of hex stock I had. It “should be brass”. and I believe it is 360 brass (free machining brass) so it has a higher lead content and hence the colour. Should it fail, well, can always make another out of yellow brass.

 

[Brent H]

ACME threading, the on going saga.....

Part of my restoration is to make a new tailstock quill and then line bore the tailstock and fit the new quill. I made a quill already out of 4140 and bored in a #2 Morse Taper and then also bored the hole at the aft end for 9/16 -8 LH ACME threads for the existing hand wheel. Cutting those threads in the 4140 ended up a failure as I found that given the right (or wrong really) engagement of the thread feed, it can occasionally lock in about a 1/4 thread out - argh! - yes, that means making a new 1/2 nut assembly at some point. It only takes once and the threads are not really that great .....

Today I proceeded to make a new cross feed nut. This nut is also 9/16-8 LH ACME. The original nut is bronze but I made the new one out of Brass. I machined the nut blank on the mill out of a 1-1/2” piece of round stock that I cut to length and then faced to final length on the lathe. (About 1-3/8”).



Adding a chamfer:


After making the blank I marked it for the thread holes (one for the feed screw and one for the cross feed retaining screw. I mounted the blank in the lathe using a dead centre between the punch mark in the blank and the live centre in the tailstock. I then used a dial indicator against the dead centre and adjusted the 4 jaw chuck to remove any run out showing on the dead centre. I drilled out the blank for an OD of about 0.4180”. Then I was off to ACME threading.

The final result:



I used the tailstock ACME thread as a guide and it fit great, snug but worked back and forth easy. The Cross Feed screw was tight at the start but once over the newer part of the threads it was a good fit.



Once re-assembled I checked the backlash and it had come from 0.025/0.030” down to 0.004”. Yee Haw!!

Also, I purchased a new 60° end mill and used it to clean up the top slide dovetails. I machined off a total of 0.007” one side and 0.004” on the other- just into the tight corner of the dove tail. On one side I did get a few areas where the tool was cutting a bit more than others and the sides of the top slide dovetail were nice and smooth. It works great now with the new nut and clean up machining.

Next up will be line boring the tailstock .......

 

[Brent H]

So, Boring a tail stock on the lathe......

This project is still on the go but almost completed so I will update things now and see what you folks think.

I read quite a bit about how not to do this and that it would be quite impossible (perhaps it is and I will find failure in the end) but I was willing to risk is the quill or spindle was in rough shape and there was a lot of play in the assembly when you put out about 2 inches of the quill. Probably not as critical for drilling things as the bits can somewhat achieve a reasonable center and then you can bore to a proper concentricity but using the "center" to hold things on center or to establish a center was pretty much useless. There was about 5 or 6 thou side to side play and about 25 to 30 up and down. The tail stock did function quite a bit better after I raised it 0.010" by shimming it between the bottom plate and the top. It turns out that a couple of carefully cut beer cans make a good shim.

I machined a blank to the size of the tail stock quill in the 4 jaw and then slid the tail stock up to it and then shimmed/adjusted until the tail stock would slide on without smacking the top. That gave me the shimming for the tail stock and greatly improved drilling and centering.

The quill has seen many a battle and sports quite a bit of damage from over tightening the jam nut. If I was not going to line bore the tail stock, I had to at least make a new quill. Here is the old one:


Note the double key ways. This was done as some one had crushed the original key way - also note the big ding near the end of the top key way.


This is the inside end of the quill. Note the scoring- how does that happen?



Here you can see the mashed over lower key way and you can just see the oil grove at the top of the quill. By machining in the new key way the oil grove was rotated off of top center and was essentially useless. There is a small hole at the top that would allow oil to drip onto the feed screw from a gits oiler on top of the tail stock.....well the wee hole was plugged with crud and not much oil was going anywhere.

I have machined a new quill complete with a #2 Morse taper front hole and also 9/16 - 8 TPI Left Hand ACME threads as per the original. The feed screw was in surprisingly good condition and fits the new quill very well. The new quill is 1.588" in diameter with less than 0.0003 across its length of 7 inches. The old one measured 1.576 at the morse taper end and 1.5715 at the feed screw end.

Here is the new one beside the old one. I still need to mill the 1/4" key way and oil slot. I would like to add the graduations (3 inches worth) if someone has a cool idea for that. I will probably have to use the rotary table very carefully..



More to come on the line boring....this is why the new quill is 1.588" as I did the boring....

 

[Brent H]

So carrying on with the line boring part of it ( the new quill is 4140 steel by the way) I bored the tail stock out on the lathe by making up a line boring jig and then using the feed on the lathe to drive the boring tool.

It was pretty darn close to not being able to fit with the jig I made but it ended up working quite well. The tool inspiration came from watching a few you tube videos on some guys who have bored their own tail stock.

Here is what the assembly looked like:



I had to maximize the length of the boring capabilities so I took off the chuck. Way back at the start of this project you may note that I had the old three jaw chuck original to the lathe (I think) and the jaws were worn out. Well the D1-3 face plate made a good fit and I machined a bit out of its center to get a true hole. I then press fit in the steel bushing that drives the boring bar. At the end there was no detectable run out at the boring bar closest to the face plate.

The bar is 1" shaft stock and runs pretty true. With the assembly as shown I was able to get less than .0005" at the max distance with respect to run out and it ran well. I fabricated the bearing support on the mill out of 1/2" and 5/8" steel plate. I surfaced everything and after welding it went back into the mill to square the bearing support face to the tool holder face.





It worked out quite well as I could use the cross feed and the tool post to micro adjust the boring bar to achieve near zero run out.

The bar is slotted for a key all the way along and this is what I used to drive it. I sunk a set screw into the face plate end bushing and locked it into the slot so the boring bar could move along the key way and rotate at the same time. I drilled out for a 1/4" High Speed Steel cutter and ground it into a decent cutter and secured it in the bar. I put a set screw in at the bottom for fine adjustment and 2 locking set screws in the side of the bar to retain the bit.



I ran the lathe at 300 RPM with a 0.002" feed and cut from the front to the back of the tail stock removing only enough material to get all 4 sides clean. I had to stop short of the end as there is a bearing retaining Cir-Clip grove that I didn't want to cut into. The cutting process took about 20 minutes with only 2 passes and left a really smooth finish on the cast iron.

I machined a piece of steel down very slowly until it just fit into the bore of the tail stock. This mic'ed out to be 1.5880 and is a snug fit.

Hopefully, the bore and new quill will work together. I have also machined a new jam nut out of brass and made a new key/jam nut screw that should solve the mashing of the key way issue on the quill.

I won't be able to test/complete this all until I get back from work, but fingers are crossed. Once this part of the restore is completed it will be on to learning how to machine bevel gears......

 

[PeterT]

I'm not getting your picture attachments in last couple posts for some reason,

 

[John Conroy]

I'm not getting your picture attachments in last couple posts for some reason,

Same here.

 

[Brent H]

I refreshed the screen and they came up for me? Maybe I need to drop the resolution?

I will try to resize?

 

[PeterT]

yup, that worked. Thanks!

 

[PeterT]

Nice restoration. I have an ill-fitting keyway slider that was apparently chewed by a Taiwanese rat after inspection. Shockingly, the only issue was a bit of rotational slop of the quill when loaded under torque. It is hardened but I was able to stone it for a better fit but I think I'll make a new one one day. The keyway slot itself wasn't bad but not great, so they kind of worked despite themselves.

The only difference of my quill is what looks like an inserted brass or bronze leadscrew nut on the end. Your original was threaded in the blank itself?

This also got me thinking. This mini key is the only thing resisting torque like when the tailstock quill is fully loaded with a big drill. In other applications on the lathe, the last line of defense is typically lower strength material like say the brass shear pin on the power feed or threading bar. I guess there is a lot more expensive gears at risk. But would it mkae sense to have the key made of brass to shear or at least not mangle the keyway slot? Is yours steel?

 

[Brent H]

Hi Peter,

From the looks of your quill screw end ....hahaha ...(not being personal or anything)...that would be a modification/original to fit an insert? My original is threaded :



That being said, the insert is nothing bad and I note that your's is pinned on two sides - that would help to resist spinning and secure the insert. Some tail stocks have replaceable threaded inserts so it should be fine. Had I failed to machine new threads I would have made an insert. Lots of the older lathes have cast iron quills and are not hardened or plated etc. they last many years.

The key on mine is part of the threaded assembly for the jam nut. Essentially a landing that sticks out into the tail stock. You can see it in the side of this tail stock pic:



I think the key should be steel as it needs to resist the torque, it should also fit very well - a good depth of contact in the key way. from the above pic you can see that the key sticks out pretty good and is a solid 1/4" x 1/8"

 

[PeterT]

Nope the quill is stock with replaceable? bronze or brass threaded insert.
You might have to lower res your pics again, cant see them