PDA

View Full Version : Chuck mounting for live tailstock



old mart
03-22-2019, 10:54 AM
We were given a Pratt 4" chuck with a backplate which turned out to be for a Myford lathe. The mounting threads are 1 1/8" X 12. The museum's lathe has more than enough chucks, so I have repurposed it.
For a modest sum, there is a MT2 live centre with the Myford thread available from India: https://www.ebay.co.uk/itm/Triple-Bearing-MT2-shank-Revolving-Lathe-Tailstock-Chuck-Adaptor-Myford-thread/223129208705?hash=item33f3898781:g:ccgAAOSwfpVZMl4 Y
The backplate screwed on and I was not impressed with it at first. It had about 0.010" play in the bearings. Cheap and nasty was my initial thought, but being a great optimist, I decided to give it a little squeeze under the press. There was a bang as one of the bearing races moved and now there is a slight preload and the slop has vanished. As it will never be run over about 300 rpm, I think it will be allright.
To skim the mounting face, I set up a MT2 turret lathe socket in a chuck and got it running dead true to hold the live backplate assembly for turning. A length of 2" copper water pipe had a lengthwise section cut out of it and was secured both ends with hose clips to provide the drive.
The threaded nose had a centre already in it which I was grateful for as the overhang was fairly long.
While trueing up the mounting face, I made a second mounting for an 80mm chuck from my 7X12 home lathe, so now it can mount a 4" or an 80mm chuck.
Testing with the 80mm, I managed to get the runout down to 0.002" tir, which is good enough for me.

Doozer
03-22-2019, 11:11 AM
I never had the need for a live tailstock chuck.
Do you have a specific use?

-D

old mart
03-22-2019, 11:29 AM
No, I don't, but it might come in handy for tubes or large stuff one day. Mods to the lathe I have made include positive locking of the spindle thread for safe running in reverse, rear mount toolstock for 26 and 32mm upside down parting off blades, a dedicated boring bar holder for 12mm solid carbide tooling which also holds 26mm parting blades and micrometer stops both sides of the saddle. Also a toolpost grinder for chuck jaws, fixed steadies and a number of new gears for metric pitches if required.
Lots of these mods will have limited use, but they could save the day once in a while.
How is Buffalo? I was there in 86 doing a course on aircraft oxygen equipment at Scott Aviation.

BCRider
03-22-2019, 11:44 AM
My brain started rumbling after reading this with thoughts on uses. Like Doozer only a few really percolated to the top.... Your suggestion for pieces of large size pipe being a good one.

But then I started wondering about the idea of a modest sized four jaw that might work for holding oddly shaped items.... That could be a nice option too.

CCWKen
03-22-2019, 12:17 PM
I have a Jacobs 100 (?) chuck with the brass jaws for the tailstock. That ranks right up there with the live center chucks. :D I think I've used it once on a motor armature. I also have a Jacobs chuck that screws onto the headstock thread (1 1/2-8) and I've never used that one. :cool:

But just having them makes me prepared. :D

Doozer
03-22-2019, 01:56 PM
...
How is Buffalo? I was there in 86 doing a course on aircraft oxygen equipment at Scott Aviation.

I live down south now. I lived there most of my life and I still take vacations there.
I work making door closers and door operators now, and my manager used to work
at Scott before coming here. I am going to Buffalo in a week or 2 to visit friends
and the food. Great architecture there too. Buffalo is coming back as a city, but
will always be known as the slowest train wreck in history. Started with the Welland
Canal, which allows ship traffic to go around Niagara Falls, where previously all ships
had to stop and offload at Buffalo. I finally shipped out to go south, and now I have
5 acres of land and a pretty large shop.
Cheers!
-Doozer

old mart
03-22-2019, 02:39 PM
I loved going to see the USS Little Rock at the museum, and of course, Niagra is just down the road. And I walked across the Peace Bridge into Fort Erie, Canada.
A small independent four jaw would be the best type to have on a tailstock, but I only had the three jaw ones.

enginuity
03-22-2019, 04:33 PM
I never had the need for a live tailstock chuck.
Do you have a specific use?

-D

I've seen guys use it for large pipe.

Arcane
03-22-2019, 05:05 PM
I have a small three jaw chuck that has bearings attached to the face of jaws and the backing plate just slides over the nose of my 9" SB tailstock ram and is secured with two setscrews. It came with a small Atlas lathe I had bought and fixed up for resale and I kept it. I've used it a few times to hold pieces of pipe and tubing but I think a revolving chuck would be better but since it was free, I'm not complaining!

Oldguy
03-22-2019, 06:15 PM
Mods to the lathe I have made include positive locking of the spindle thread for safe running in reverse

Have you ever posted details?

Glenn

old mart
03-22-2019, 06:20 PM
I would like to post photo's, but I'm not ever going to use any of those hosting sites.

elf
03-22-2019, 07:08 PM
One would be quite useful for putting the workpiece under tension instead of compression. What size is a Myford thread?

old mart
03-23-2019, 02:43 PM
The most common Myford spindle threads are 1 1/8" X 12, but the earlier lathes had 1" X 12. Putting the workpiece under tension would be limited by the Morse taper most likely, although the bearings in the MT/chuck adaptor I bought are pressed together with nothing more than interference fits holding the assembly together.

J Tiers
03-23-2019, 04:34 PM
I would like to post photo's, but I'm not ever going to use any of those hosting sites.

Send them to someone here to post, or use the attachment hosting that is right on the actual forum site. Lot's of folks would like to see the mod.