Does anybody have any tips for turning S154 steel on a STAR sliding head machine? I'm getting drag marks on the finished part. Using VCMT 160404 inserts.
Bar diameter 16mm. Depth of cut 5mm. 1800rpm 0.04mm/rev. This works but anything quicker and the material just tears.
I've tried different chipbreakers & grades.
Any suggestions???

Sharper insert. Have you tried a cermet? Something else to look at is are the chips hitting the finished surface? I know it sounds stupid but you'd be surprised much chips falling away from the cutting tool can affect surface finish. Try redirecting the coolant to blow the chips away from the finished diameter. You can always try to rewrite the path too but you might be limited since your on a screw machine.

:cheers:

I would trade that machine for a Citizen with their 2000psi coolant pump to help break or at least control the chips.