Hello, first post here. I feel like I'm losing it a bit here. My G code (according to my eyes) is correct I think. I keep having troubles with this internal toolpath.

It seems like no matter what I do, I keep breaking inserts/destroying tools. Any other thread (npt or otherwise) I have zero problems with.

OK, so here's the setup.

Machine- Okuma Lb3000 EXII

Tap drill- ISCAR SumoCham 5x drill w/ .437 insert

Threading tool- Carmex 08IR with 18 npt laydown threading insert. Recommended sfm 295 min 450 max in SS

Material- 303ss

My process-

Drill, put on 30* cham (as per our company req.), THEN cut the taper for the NPT, after that I thread with a G71, chase/top threads with boring bar, rerun threading cycle.

Code-

G71 X.540 Z-.4375 H.088 B60 A-1.79 D.023 U.0005 Q1 M32 M73 F.0556

RPM's- 2000 as per my math for correct sfm on the insert. (3.82x295)/.540. Initially, had the RPM's @ 500 but changed to be in line with the inserts "requirements".

I don't have any one to bounce ideas off at work and am completely at a loss for what I have wrong. If you have any advice, I'd truly appreciate it.