Threading with triangular inserts

Jan 14, 2009 7 Replies
I

I have a straight toolholder that takes a T P G 322 insert. I would like to know if I can find an insert like this that would have a small enough edge radius to be used for threading.



By the way, I am fully convinced now that flood cooling is the way to go anywhere where heat is an issue. For example, yesterday I parted a steel bar, which always was troublesome due to heat. No problem with flood coolant. The only minus with flood is that I cannot use my lathe try as a shelf to keep stuff. No big deal. No rust seems to result from flood coolant either.


Vote
Twitter Facebook LinkedIn
J

Tip radius for TPG322 is 1/32", for TPG321 it's 1/64". According to my homemade hand grinding chart 0.016" is about right for 8 - 12TPI. You could try it on finer threads and drill out the female thread a little if it doesn't fit well.

jw

Vote
Twitter Facebook LinkedIn
J

download and install the thread calculator on this page Ig.

formatting link
A Zero TNR is about .003"-.005". A one is .015". You can purchase threading inserts if you need to hole print tolerances but what you need to worry most about is the pitch diameter and form.

JC

Vote
Twitter Facebook LinkedIn
K

Carbide likes higher speeds and deeper DOC. This makes using it for manual threading difficult at best. You'd do best to stay with HSS.

Now for my CHNC lathe, I use carbide threading inserts and thread around 2000 RPM. Works great. But these aren't TPG, they are just for threading.

Karl

Vote
Twitter Facebook LinkedIn
P

Yep. Check this link:

formatting link
I've used the smaller radius inserts for threading. They also have dedicated threading tools which look nice, pricey though. Their inserts are T-15 HSS, and pretty sharp. They're nice folks to call and talk to.

Pete Keillor

Vote
Twitter Facebook LinkedIn
R

Pete sez: Yep. Check this link:

formatting link
Nice site Pete. Thanx. Inserts are great for threading but don't forget the absolute minimum-radiused nose for fine threading can be achieved with HSS.

Bob Swinney

Vote
Twitter Facebook LinkedIn
P

These are HSS inserts. You can grind them as well, say for lead angle, although I haven't tried that. Dick Triemstra got me onto these when he sold me the lathe in 2001. They're better than carbide in most instances for the low power, less rigid machines we hobbyists have. Yeah, I do grind HSS for some stuff, internal threading, shaper bits, etc.

Pete Keillor

Vote
Twitter Facebook LinkedIn
I

My lathe is 3 HP, 1,400 lbs. So it is heavy enough for carbide.I have looked a lot at carbide threading tools, on ebay, and I have not found anything worth buying. I will stick to HSS tools for now.

i
Vote
Twitter Facebook LinkedIn

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required