Insert, TCMT-21.50 Carbide

The 7° relief on this insert gives noticeably cleaner cuts on my stainless steel parts compared to the last ones I tried. That single-sided chip breaker does a good job keeping the chips manageable, and the 1/4" IC size fits my holder perfectly.

I’m surprised how the 7° relief angle and chip breaker handle light finishing cuts without any chatter. The single countersink hole sits flush on my tool holder, and the 0.25" IC works perfectly for small parting work.

Finally tried these TCMT-21.50 inserts with the single-sided chip breaker, and they really do keep the chips from wrapping around the tool. The 7° relief is just right for the stainless steel parts I’m turning.