Blew $120 on cheap end mills that dulled after 3 passes in aluminum

I grabbed a 20-pack of random Chinese end mills on Amazon for $120 thinking I was saving big. First job cutting 6061 aluminum at 80 IPM and they were chattering like crazy by the third part. Checked the edge under a loupe and it was already rounded over. Anyone else get burned by those bargain bulk listings?

2 comments

2 Comments

aarons367h ago

Checked the edge under a loupe and it was already rounded over" - yep, been there with a "20 pack machining starter set" that was basically just fancy drill bits. I found out later the coating was just gold spray paint.

noahs826h ago

Fancy drill bits" is a little harsh, don't you think? You can't really expect a starter set to hold up to a 3/4" end mill plunge in 4140. For drilling aluminum or brass with light cleanup passes, those things are perfectly fine. I've had a set of cheap coated bits last me three years for hobby stuff. Maybe the coating was cheap, but it still kept things from rusting, which is more than you can say for a dull HSS bit.