Starting a thread on the lathe with a die

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

Moderators: GlennW, Harold_V

RSG
Posts: 1541
Joined: Fri Feb 04, 2011 9:59 am
Location: Ontario, Canada

Update - Starting a thread on the lathe with a die

Post by RSG »

I thought I would post a quick picture of the parts I finished after receiving sage advice on how to thread stainless using dies. Every once in a while you get advice that is spot on and it's worth mentioning when it happens. One of the methods written about was to machine a shoulder to the minor dia of the thread and add a taper so the die would both align and start easily. Well this little tidbit of info made the deference between success and failure. I just wanted to say thanks for the awesome advice guys, so glad I am a member here.

Image
Vision is not seeing things as they are, but as they will be.
whateg0
Posts: 1114
Joined: Sat Mar 28, 2009 3:54 pm
Location: Wichita, KS

Re: Starting a thread on the lathe with a die

Post by whateg0 »

Those parts look nice!
RMinMN wrote: Tue Jan 02, 2018 9:08 am...If you cannot have a runout groove you will need to turn the lathe by hand which is easiest done if you have made a crank that locks into the spindle. Even if you do not make the thread full depth it will help guide the die and keep it threading true and it takes a lot less force to cut a shallow amount of thread with the die than full depth.
That's what I've done on my old lathe that even at its slowest (no backgear, sorry), was way to fast to thread 12 tpi. For one or two parts every once-in-a-blue-moon, I just turned the chuck with the chuck key, but a handle shoved in the spindled would have been nice. I also frequently cut threads almost to full depth, then chase them with a die. Makes the chasing pretty easy.

Dave
Rwilliams
Posts: 1048
Joined: Thu Dec 22, 2005 2:45 pm
Location: Central California

Re: Starting a thread on the lathe with a die

Post by Rwilliams »

Recently I had to cut a 12-32 thread to a shoulder but did not want the starting groove of an upside down threading tool.

Solution was to cut about an 80 percent thread almost to the shoulder going very slowly to insure a safe stop situation.I then used a special guide in the tailstock drill chuck to insure a nice square start to the incomplete thread. The hand die holder easily cut the last 20 percent of the thread almost to the shoulder. I then reversed the die in the holder and ran it over the thread to bring the thread as close to the shoulder as possible. Took some time but worked well.
Post Reply