My brand new 5/8 end mill snapped on the third pass. Here's what I learned.

Bought a fancy new 5/8 three flute end mill last week. Thought I was being smart taking light cuts. Third pass on some 6061 aluminum and it just snapped clean off. No warning, no weird noises. Just a loud crack and there went $85. Took me an hour to extract the broken piece from the vise. Talked to a guy at the local sharpening shop and he said my rpm was way too low for that cutter. I was running around 3000 rpm when I should have been closer to 5000. Live and learn I guess. Any of you guys had a tool fail in a dumb way like that?

3 comments

3 Comments

leo23813d agoProlific Poster

Crank that rpm up around 5000 and you won't snap another one.

dylan_green5813d ago

Were you running coolant or just blasting it with air?

troyjackson13d ago

yeah i was just using air honestly. i feel like people overthink coolant for stuff like this, half the time it just makes a mess and doesnt even do that much. reminds me of how everyone thinks they need the most expensive gear for basic stuff when a shop rag and some patience gets you just as far. not saying coolant is bad but for a quick cleanup like this air does the job fine.