Tail-stock die-holders

All discussion about lathes including but not limited to: South Bend, Hardinge, Logan, Monarch, Clausing and other HSM lathes, including imports

Moderators: Harold_V, GlennW

martyn
Posts: 66
Joined: Sat Jan 07, 2012 3:54 am

Tail-stock die-holders

Post by martyn » Sat Mar 31, 2012 9:22 am

Don’t want to be boring about why I have a c-----e lathe, but… here in France, where there is no ‘home machining’ culture, the admittedly voluminous list of quality domestic makes warrants a book that’s yet to be written, and some sort of second hand clapped out WWll obscurity is likely to be 1000 kilometres away, rather than, as with you guys, a pristine Southbend a few blocks away, is a lot to do with the explanation !

To the point – you all know most oriental ‘jobs’ in my price bracket drive by belts. No back gear. Thus no facility to run r-e-a-l-l-y slowly. (Say 20 rpm). You get what you are given and my slowest is 160.

This, as I interpret it, precludes using a tail-stock die-holder in the intended way.
(I think, maybe wrong, you hold the workpiece in the headstock chuck, run at ultra slow speed and advance the tail stock barrel and the die-holder held therein in something like a Jacob’s Chuck, with the tail stock feed wheel while steadying and fine-tuning the die-holder with your hand on the knurls on the die-holder barrel.)

Could you, therefore, put a few ‘pilot’ threads on the workpiece with a die in a manual die stock at the bench in the conventional way, then hold the workpiece in the headstock chuck, rotate the latter by (left) hand and advance the tail-stock die-holder (fitted up as described) with your other paw (right) ?

Reason I think I want to do this is I have a long (5/16 BSF) adjustment thread to cut on a brake rod. We’re talking about three/four inches which sounds to me a bit cumbersome, inaccurate, die-endangering, in the bench vice with a hand held die-stock.

As always, thanks in advance for any views.

Martyn (my 63rd birthday today so a nice way to spend it talking to you folk)

User avatar
GlennW
Posts: 6928
Joined: Sun Apr 15, 2007 9:23 am
Location: Florida

Re: Tail-stock die-holders

Post by GlennW » Sat Mar 31, 2012 10:34 am

Hello Martyn,

Happy Birthday!

I would suggest a die holder held in the tail stock to do the threading as you mentioned. The method that I use is to leave the tailstock loose enough so it just slides on the bed ways. Then just start the spindle, slide the die up to it, and let the threading action pull the tailstock along the ways. Depending on the length of the holder and the depth of the chuck, fairly long threads can be made and they usually stay pretty concentric.
P1010395.JPG
Use lots of cutting oil!

I have made different sizes to accomodate different size dies. One I made with a hex area on it so a wrench could be used if needed as they have a tendancy to turn in the chuck with larger coarse threads.
P1010497.JPG
They work well for external pipe threads as well. The larger one in the pic was used for 3/8 NPT.

I like the dies to fit nice and snug in the holder and to be locked in using opposing set screws.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

Russ Hanscom
Posts: 1767
Joined: Wed Mar 15, 2006 11:10 pm
Location: Farmington, NM

Re: Tail-stock die-holders

Post by Russ Hanscom » Sat Mar 31, 2012 9:44 pm

Being a bit cautious, I use the rig in the picture; the section with the die holder and handwheel is free to slide on a stub in the tailstock. When the thread is to length or when the torque gets too high, I just let go of the handwheel and threading stops.

Like Glen, I have an assortment of die and tap holders to fit most sizes.
Attachments
DSC00536.JPG

martyn
Posts: 66
Joined: Sat Jan 07, 2012 3:54 am

Re: Tail-stock die-holders

Post by martyn » Sun Apr 01, 2012 3:02 am

Many thanks guys. I'll go with that.

Martyn

User avatar
refinery mike
Posts: 623
Joined: Sat Jul 02, 2011 1:54 pm

Re: Tail-stock die-holders

Post by refinery mike » Sun Apr 01, 2012 9:21 am

Martyn,
I believe you need that thread to be three or four inches long. most die holders will not go that far. I am inclosing a photo of a die holder that goes on the cross slide of the lathe. It take a little time to set up perfectly square but it will thread any length of thread.

I simply clamped a large block of steel to the cross slide of my lathe (with two through bolts and a plate in the t slot.) I squared the block up with my face plate to insure it was square and then put a 19MM hole through the center of the block with a bit in the head stock. (I used a Morse taper to chuck set up) After drilling i clamped the block to the face plate and bored out a counter bore for a die. That kept everything right on center. It would be best if you could get an adjustable high speed die. then open it up and run the rod through and then tighten it up to finish size and make a second pass. (even though you loosen the die bolt to tighten it up and tighten the die bolt to loosen up the thread)
Never the less i have used this set up with standard dies to good success.
As far as the speed goes, i would think a high speed die would handle 160 RPM on a 5/16 inch rod.
The quality of the photo is not great but i think you will get the general idea. I did not have time to set it up it is just setting on the cross slide now, but i am sure you can figure it out, if not i will set it up and post another photo.
Attachments
die holder.jpg

JackF
Posts: 1572
Joined: Mon Jan 26, 2009 3:56 pm
Location: Caldwell, Idaho

Re: Tail-stock die-holders

Post by JackF » Sun Apr 01, 2012 11:33 am

R Mike,

Thanks for that pic of your die holder and the description of the procedure to make it. Do you use the carriage hand wheel to advance the die for the full length of the thread or once started let the die pull the carriage?

Jack.

JackF
Posts: 1572
Joined: Mon Jan 26, 2009 3:56 pm
Location: Caldwell, Idaho

Re: Tail-stock die-holders

Post by JackF » Sun Apr 01, 2012 11:41 am

Then again,

Would it be prudent to set the lathe to the pitch of the die and use the half nuts and lead screw to move the carriage? I hope this is not another one of those dumb questions from a relative newbe. :? :wink: :lol:

Jack.

User avatar
refinery mike
Posts: 623
Joined: Sat Jul 02, 2011 1:54 pm

Re: Tail-stock die-holders

Post by refinery mike » Sun Apr 01, 2012 2:26 pm

I generally just leave the the drive and the carriage disconnected. It will pull the carriage along but i help it with the hand wheel anyway mainly so i have something to do. Just make sure everything is all square and lined up befor you start. You also could just single point thread the thing as far as that goes. If single point threading scares you it should not. It really is not all that difficult. Go on line and download the Southbend Book "How to Cut Screw Threads in the Lathe". And build a Southbend style "thread cutting stop to attach to the dovetails of the saddle." One came with my lathe and I find it very helpful.

JackF
Posts: 1572
Joined: Mon Jan 26, 2009 3:56 pm
Location: Caldwell, Idaho

Re: Tail-stock die-holders

Post by JackF » Sun Apr 01, 2012 2:40 pm

Thanks for the reply Mike,

I am not afraid to single point, have been single pointing inside and outside threads for several years. :) But sometimes I get lazy and am always liking to try a new method. I have used dies on the lathe many times but just mount them in my hand held holder and square the die up with my 3/4" drill chuck with the jaws opened up but am limited to the depth of the drill chuck. I like your through hole die holder mounted on the cross slide.

Jack.

spro
Posts: 8006
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Tail-stock die-holders

Post by spro » Mon Apr 02, 2012 2:12 am

later
Last edited by spro on Tue Apr 03, 2012 6:06 pm, edited 1 time in total.

JTiers
Posts: 422
Joined: Fri Jan 22, 2010 12:55 am
Location: Missouri

Re: Tail-stock die-holders

Post by JTiers » Mon Apr 02, 2012 8:01 am

For the long thread, the die won't hold a good pitch.... if you can single-point the thread with the lathe, it will be more accurate. if no concern for exactness, you can do the thread without using the lathe at all, just the die in a hand diestock and work in a vise.

if the concern is the lathe speed, which I agree is an issue with most asian machines, there are solutions.

1) modifications..... There are a number of modifications for the smaller machines to get low and controllable speeds. Since you ahve 160 rpm, probably you have one of the "230 x 500mm" size machines, since larger ones are doen to 100 rpm. Look around on teh web for your machine.

2) releasing die holders..... you can thread at virtually any speed with these, and you can make them yourself.

here is a releasing tap holder, but a die holder would be about the same.... Advance the T/S until the tap "starts", then stop advancing... the pin drives the tap until it slips off the block and spins free.... then you reverse the machine, and advance just a bit more to engage the pin again. it backs out as you reverse the tailstock to a disengaged position.

Depending on the depth you want, you change your advance distance. Idea is out of "Toolmaking 1935", a Lindsay reprint book, unfortunately not available overseas, most likely.

original type has a setup such that it engages on pull back, avoiding the need to advance and then retract to back out the tap (or die)

Starting position
Image

Positioned about to "release"
Image

Edited because one sentence didn't make sense

martyn
Posts: 66
Joined: Sat Jan 07, 2012 3:54 am

Re: Tail-stock die-holders

Post by martyn » Tue Apr 03, 2012 8:20 am

Overwhelmed by helpfulness on this!

Am currently making an adaptor for the tail stock die-holder I have chosen to do this. Smallest and lightest I have of three, so I can fit it to a Jacob's chuck on the lathe.

Hope to cut the thread tomorrow. Will report back.

Thanks again.

Martyn

Post Reply