[Driftwood]

Hi all,

I'll be doing a job in a couple of days where I need to put a M42x2 external thread on a Nitronic 60 bar (similar to SS316).

I've done these parts before and the front thread always comes out sharp with burrs. Previously, the best solution I found was to put a 45 deg lead chamfer on the thread, and to do a clean up pass with the chamfer tool after threading, followed by a final spring pass with the threading tool. But we still had to touch up all the parts with a file, and I want to avoid that.

I'd like to learn to do a Higbee cut on the first thread, and have tried to do it before on different parts, but never got it to work. If anyone out there is good at doing these and can help, I'd appreciate it.

FYI:
1. my machine uses G32 for threading, not G76. For example: G32 Z-1. X2. F0.1, the machine will feed in to Z-1. then rapid to X2.
2. My threading bar uses those 3 edge triangular single point inserts, so typically when I take the offset of the threading edge, I use the edge of the insert, not the tip, and just thread approx 0.1" deeper in my program.
3. The Higbee cut, I would probably be doing with a 1/8" parting tool, as that's probably going to be the only grooving type tool I'll have on the machine

Thanks in advance...

[Thawk53]

Driftwood,
It's not that difficult at all. Position the tool you are using (parting tool) to the same starting postions as your threading tool. (Be sure to run the same RPM and feedrate as the threading tool.) Now just use the same threading cycle you used to thread the part. You don't have to make as many passes as the threader, it's up to you. It would probably be easier for you to use a smaller Z minus number in the program to start with, and then keep adding to the Z minus in the program until you are happy with where the tool is pulling out.
Hope this helps.

Rick

[BobWarfield]

There's a couple ways to do this. You can also use a G32 (tapered thread) cycle. My notes on how to do these are on my blog:

www.cnccookbook.com

Search "Higbee".

Best,

BW