Threading noob

[FrankieB]

Hello all, i am single point ID threading mild steel. I am having some chatter issue on the last 2-3 passes. Any suggestion on rpm and doc to help correct this.
Machine sl30
Insert is a lay down style sumitomo on a 1.250 bar
Thank you
Edit: current rpm is 400, doc is 0.005 finish doc is 0.002 radially

 

[maguilera]

What thread pitch and diameter? Also would be great if you share the threading section of the program.
Cheers.

 

[FrankieB]

What thread pitch and diameter? Also would be great if you share the threading section of the program.
Cheers.

Thanks for the reply but i got it figured out. I beeded to increase the first pass doc so the rest of the passes would also increase. I also increased the final pass doc.