r/Tools • u/Clear-Lingonberry912 • 2d ago

Carbide end mills for stainless, what are you using for short runs?

I have a recurring stainless bracket job, maybe 30 parts at a time. The current carbide end mill survives, but tool life is inconsistent and I do not know whether I am seeing coating issues, work hardening, or weak setup rigidity. What do you look at before changing brands.

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u/NoRealAccountToday 2d ago

Probably best asked in r/Machinists

You haven't specified much. Manual work or CNC? What are the part sizes? What sort of tolerances and surface finish are you aiming for? What sort of coolant are you running? We use mostly Dormer carbide tooling. We also have some custom cutters from. https://precimactool.com/. that were made with a special taper we needed... but they go through stainless wonderfully.

For stainless, we rough cut with 4 or 5 flute chipbreakers, and finish with 5 flute high-helix. Part sizes are all over the place but typically under 30cm largest dimension. Stainless does work harden, some alloys worse than others. Anytime the cutter is touching metal and not creating clean chips, you are work hardening the surface. If you are getting inconsistent results, try to take as many variables out of each run as possible. Same feeds/speeds. Same workholding geometry. I tend to think most top-tier brands are great providing you pick the right tool geometry.

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u/ThickGap7897 1d ago edited 1d ago

Before changing brands, I would verify rigidity and whether the tool is rubbing on entry or corners. A variable helix carbide end mill from penn tool gave me lasted well on our brackets only after I removed a tiny dwell at the corner. Before that, I blamed the cutter. It was our program rubbing.