ah, so Brents lathe did originally come out of a school
Probably explains the metric as well for a older lathe....I can remember in high school machine shop when they came around and changed all the leadscrews, feedscrews and gearboxes to metric
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Restoration of a 10” Utilathe - the metric version!
- Thread starter Brent H
- Start date
ah, so Brents lathe did originally come out of a school
Probably explains the metric as well for a older lathe....I can remember in high school machine shop when they came around and changed all the leadscrews, feedscrews and gearboxes to metricI was going to guess the same thing. During The Great Transition (that kind of occurred in fits & spurts depending on what industry you were in) some metric machines started to show up in schools & institutions. According to my buddy who was in trade school then, it was a bit of gong show, at least where he was at. The lathes were replaced, but not the mills or other machines for whatever reason. Maybe they were more expensive or alternatives were inferior. And for a while with they operated swapped metric machines but still had IMP mic's & indicators & measurement tools. The lucky folks were the ones that got the 'redundant' IMP spoils of war as they were auctioned off.
Brent H
Ultra Member
I don't have a lot of parts with me on the ship - carrying things from a lathe on a plane....well that is hard to do. I did bring a few small pieces - like the feed handles for the cross slide and the compound. You can see them in the following picture and in what condition they were in. Only a few parts of the lathe were exposed to the elements for some reason. The cross slide feed handle was mangled to crap and you can see that it is bent and in the totally wrong orientation.
Some soaking in Evaporust (not sponsored) for a day and then getting the torches out and gradually heating the handle and bending it back into shape, I now have a reasonable cross feed handle with some unique patina:
The compound feed came apart and was soaked and then some light oil and re-assembled:
This next picture is literally looks like a kick in the nut. The bronze cross slide nut is pretty beat up and I have to replace it. This nut appears to be a rather rare 1/2" x 2.5 mm pitch trapezoidal SOB that needs to be re-made. As I was on the Plane I could not take the shaft with me to make a nut and check the fit....ugh! anyway, the plan is to make 3 taps out of 4140 and harden them to cut new Imperial Metric threads and make the gears for the threading dial. I need TR 1/2"x 2.5 mm RH, TR1/2" x 2.5 mm LH and a 7/8" x 4 mm LH tap or hobb for the gears. - this will be fun!
While I am on the ship I am ordering in a bunch of stuff for the lathe: new (17) truarc ring 5100-156 for the feed train gear, a new Bijur B5944 oil Sight for the gear box, a new 1-3/8 knob for the feed selector, and a new 6" cast iron hand wheel for the apron. That was off my quick inspection list before I left. - Oh and another VFD...
When I get back I will strip things down, remove the paint, weld up and grind any imperfections and see how things are - like bearings and seals. Then paint and re-assemble. easy peasy lemon squeezy!
I am working on the metric gear drive fab plans for the threading dial.
Some soaking in Evaporust (not sponsored) for a day and then getting the torches out and gradually heating the handle and bending it back into shape, I now have a reasonable cross feed handle with some unique patina:
The compound feed came apart and was soaked and then some light oil and re-assembled:
This next picture is literally looks like a kick in the nut. The bronze cross slide nut is pretty beat up and I have to replace it. This nut appears to be a rather rare 1/2" x 2.5 mm pitch trapezoidal SOB that needs to be re-made. As I was on the Plane I could not take the shaft with me to make a nut and check the fit....ugh! anyway, the plan is to make 3 taps out of 4140 and harden them to cut new Imperial Metric threads and make the gears for the threading dial. I need TR 1/2"x 2.5 mm RH, TR1/2" x 2.5 mm LH and a 7/8" x 4 mm LH tap or hobb for the gears. - this will be fun!
While I am on the ship I am ordering in a bunch of stuff for the lathe: new (17) truarc ring 5100-156 for the feed train gear, a new Bijur B5944 oil Sight for the gear box, a new 1-3/8 knob for the feed selector, and a new 6" cast iron hand wheel for the apron. That was off my quick inspection list before I left. - Oh and another VFD...
When I get back I will strip things down, remove the paint, weld up and grind any imperfections and see how things are - like bearings and seals. Then paint and re-assemble. easy peasy lemon squeezy!
I am working on the metric gear drive fab plans for the threading dial.
Brent H
Ultra Member
Ok, so here we go figuring out the "metrics" of this project. The threading dial being the elephant in the room....well, the build should be easy ....ah hem...easier....as I only need 2 gears for the threading dial and not 5. The way my lathe is set up (as is most "school issue" or "converted" ) lathes they only really provide for 13 of the "most used" metric threads. This means you could cut threads down to M4 with some exceptions and M6 up pretty much good to go. EXCELLENT! this also means I only need to make a threading dial that has 2 indications - for reference I included the chart as a PDF and the QCGBX threading chart. I only require a 30 tooth and a 26 tooth follower gear to mesh with my lead screw.....beauty!
All threads other than: 0.25, 0.50, 0.75, 1.0, 1.25, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0, and 8.0 can be disregarded as they are not "metric" the chart above was done up by some dude on Practical Machinist that has some issues...I mean, you can cut a 1.429 thread pitch but it won't fit anything.
Anyway, according to the chart (see the PDF if you wish) I only need the 2 gears to make my threading dial.
This would probably greatly simplify any confusion for @Johnwa on his lathe as it will eliminate quite a few divisions on the dial and you only need 2 gear changes verses 5
Now to design an new threading dial that will look sexy and make Miss Metric more appealing to the folks that may enter the shop and also to Mr. Standard that will be sporting the tooling she can insert....hahaha
All threads other than: 0.25, 0.50, 0.75, 1.0, 1.25, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0, and 8.0 can be disregarded as they are not "metric" the chart above was done up by some dude on Practical Machinist that has some issues...I mean, you can cut a 1.429 thread pitch but it won't fit anything.
Anyway, according to the chart (see the PDF if you wish) I only need the 2 gears to make my threading dial.
This would probably greatly simplify any confusion for @Johnwa on his lathe as it will eliminate quite a few divisions on the dial and you only need 2 gear changes verses 5
Now to design an new threading dial that will look sexy and make Miss Metric more appealing to the folks that may enter the shop and also to Mr. Standard that will be sporting the tooling she can insert....hahaha
Brent H
Ultra Member
@Johnwa : Could you please measure the length and diameter of the rod and what is the thickness of the gears - like the total and then just the gear teeth?
I am doing up a drawing to figure out the positions I need to put those gears in - You are awesome by the way ! thank you very much for the intel
I am doing up a drawing to figure out the positions I need to put those gears in - You are awesome by the way ! thank you very much for the intel
Brent H
Ultra Member
Are the gears pressed on? Looks that way - I would probably key/set screw them. Found a similar lathe for sale on Kijiji and blew up a pic of the threading dial. Note that there are only 2 gears in use as I was planning to do.
Looks like the same housing though. Does your lathe GBX list more threads than the regular ones? Like threads for small screws below 5 mm?
From the math and your calculations it does appear it would be a 20DP cutter (I have a 14.5° PA set) and can do some tests when I get home.
Excellent info. I will post my ACAD in a few days
Brent H
Ultra Member
@Johnwa : that is crazy! completely different gear box arrangement from the pitches possible to the feeds possible. Mine has a max out of 8 mm pitch - the feed rate is 2.842 mm.
The feed rates on Miss Metric match identical to the standard lathe (0.112" = 2.845 mm) . Probably safe to assume that in my case I have the standard gear box fitted and they swapped out the lead screw to a 4 mm pitch to achieve the desired threading pitch. I will do some gear box inspection when I get home.
@Johnwa: you must have a more fully converted lathe with a full metric gear box.
By the way, I am in the process of obtaining a 1/2" x 2.5mm LH tap if you're in need of a new cross feed nut and you have the whack version of a thread like I do.
The feed rates on Miss Metric match identical to the standard lathe (0.112" = 2.845 mm) . Probably safe to assume that in my case I have the standard gear box fitted and they swapped out the lead screw to a 4 mm pitch to achieve the desired threading pitch. I will do some gear box inspection when I get home.
@Johnwa: you must have a more fully converted lathe with a full metric gear box.
By the way, I am in the process of obtaining a 1/2" x 2.5mm LH tap if you're in need of a new cross feed nut and you have the whack version of a thread like I do.
Johnwa
Ultra Member
The mm dial is set screwed to the lead screw. It has a very fine 100 tooth gear. The inch dial has a 127 tooth internal gear. Its center of rotation is offset so only a few of the gears teeth mesh. One rotation of the handle moves the slide 2.5mm, 5mm on diameter. Rotating the handle a bit further and the slide moves 0.1” or 0.2” on the diameter.
If the mm dial is set screwed to the lead screw where does the 100 tooth gear come into play?