[BlaznLow]

Hey everyone,

I am trying to turn some LH threads on our Haas lathe. The insert I am using is 16ER AG 60 IC908. https://www.iscar.com/eCatalog/Item....app=0&GFSTYP=M

The material is 17-4 PH Stainless Steel.

I have it running at 1900 RPM and 0.05 in/rev as the thread is 1/2-20.

The issue I am having is the insert keeps chipping. Is there a better insert I could be using for 17-4?

[Jim Dawson]

Try two or three more passes with a decreasing step down / pass. I was having the same problem until I did this, now I get hundreds of parts out of an edge.

[fc60]

Greetings,

For a Left Hand thread, do you not need a Left Hand tool holder and a 16EL AG60 Insert?

Cheers,

Dave

[deadlykitten]

hy, you can consider also a Rhand tool : flip it 180* + reverse spindle sense / kindly

ps : is possible also to use internal inserts on a od tool; with a bit of care, you may control the process pretty well

[BlaznLow]

I slowed it down more to 420 and lightened the cut up with some oil and it worked pretty good.
Thanks everyone for the help, its was greatly appreciated

[OldSchoolProgrammer]

Hey everyone,

I am trying to turn some LH threads on our Haas lathe. The insert I am using is 16ER AG 60 IC908. https://www.iscar.com/eCatalog/Item....app=0&GFSTYP=M

The material is 17-4 PH Stainless Steel.

I have it running at 1900 RPM and 0.05 in/rev as the thread is 1/2-20.

The issue I am having is the insert keeps chipping. Is there a better insert I could be using for 17-4?

The insert is probably OK. Full annealing of the material can help a lot. If you can't do that, you can use straight infeed on the threading tool for the heavier passes and switch to 29.5° infeed for the final two or three passes, making those only a couple of thousandths deep each. Switching from straight to compound infeed will require two separate threading commands. (Straight infeed loads the tool symmetrically and will usually prevent chipping, but it can promote chatter, so cutting speed gets more critical.) Finally, using a high lubricity cutting fluid is always a good idea when machining PH stainless steels, particularly when threading or when milling slots.

[tjm229]

The material itself is tricky especially when threading and milling. A soluble cutting fluid will be a massive help but not advisable to use on a sliding head lathe but fixed head/conventional will be fine. I would add more passes and use a decreasing step down (i think another member mentioned this also). Heat build up is the biggest issue with these stainless grades.

regards Tim

https://www.mmturnedparts.co.uk

[g-codeguy]

You were given a lot of good advice and must have solved your problem, but for future reference it helps to post the code used in making the thread. I hate lying, but I lie in threading cycles without a qualm.