Rick Finsta
Stainless
- Joined
- Sep 27, 2017
So I've got a job that uses a 0.250" thick, 0.040" double corner radius, 1.75" OD, 1/2" shank (with a small relief due to the depth of the feature) slot mill / keyseat cutter, whatever. 14 tooth, solid carbide. It is cutting 4140 at 41-44HRc. It goes in fine but then hits a cross hole and everything seems to go to hell. I am running it at the manufacturer-recommended speeds and feeds (220SFM or 480RPM)and 0.0005" per tooth feed. Thing is the chips are coming off looking HUGE after it hits that hole. It is like only a few teeth are actually cutting. At least one tooth has now chipped, and it sounds horrible in the cut (I've cut about 24 of these parts and have 8 to go). I have been climb milling but my next thought was switcing to conventional milling and upping to 0.001" per tooth and halving my SFM. Other than the one chipped flute the rest feel sharp but I don't have a microscope. No visible edge wear to the naked eye. I'm holding it in a collet and have checked concentricity. Maybe switch over to a sidelock or borrow/buy a hydraulic?
HELP! This project is way behind schedule and if I break this tool I've gotta get another custom made.
HELP! This project is way behind schedule and if I break this tool I've gotta get another custom made.