[stuby]

Hey guys, hows it going? I am in need of some assistance. I am trying to turn down the threads on some grade 8 bolts, 700 of them to be exact. We put it on our rockwell tester, and we're getting 58-60 Rc. My tooling is just not having it one bit. I can only get through about 4 parts before my inserts are done, however the finish I am getting is immaculate. I am running 850 RPM at .0055" per revolution feed (Im on a lathe, if you didnt know) and I am using a KC850 grade insert. Should I be using a HSS cutter or is this stuff just going to burn carbide being as nasty as it is? I just want to make sure my feeds/speeds arent too far out of whack before I go and buy some more expensive inserts. Thanks ahead of time for the help guys, you always come through.

[Thawk53]

What diameter are the bolts. Can't figure your surface footage without that.We have excellent results in steel at 54 Rc with Kennametal KC9110 grade.

Rick

[juergenwt]

Stuby - Pls. check your Rockwell tester. 58-60 Rc sound unreal. Like 53 said: what dia? Unless those are some very special bolts - you should not have any problems.