I finally figured out why my 0.25 inch end mills kept breaking on aluminum

For months I was running my Haas at 10,000 RPM thinking faster was better, but then a guy at the shop in Tacoma saw my setup and asked about my feed rate. Turns out I was feeding way too slow, basically rubbing the tool to death instead of cutting. I switched to a 0.002 inch per tooth feed and the difference was night and day. Anyone else have a 'duh' moment with feeds and speeds on softer metals?

3 comments

3 Comments

xena6421mo ago

Honestly, is feeding too slow really that big of a deal on aluminum? It's not like you're cutting titanium or something. I've run tools a bit slow before and they seemed fine, maybe just got a little hot. That whole "rubbing not cutting" thing gets repeated a lot, but sometimes I wonder if people are just being overly careful.

maxp681mo ago

What kind of aluminum were you cutting when it just got a little hot?

betty1261mo ago

Oh man, that's so true about the rubbing thing (it really is a killer). I see this everywhere, like when people drive with their foot barely on the gas pedal, just wearing out the clutch. The right amount of force, even if it feels wrong at first, is actually way smoother in the long run.