Old timer told me to run my end mills dry on aluminum, ruined 3 bits in a row

I was at a shop in Phoenix last month and this 30-year vet said compressed air is a gimmick, so I tried running no coolant on 6061. Now I'm out $80 on carbide and the parts had terrible finish. Anyone else get bad advice from some old-school machinist that cost you parts?

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3 Comments

taylor.amy3mo ago

Respectfully disagree - dry aluminum turns into a sticky mess without any air or lube.

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patricia_schmidt143mo ago

Worked with aluminum dry on a few builds back in 2019. Never had any sticking issues, just kept the speeds down and it was fine. Maybe it's more about the tooling than the material.

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jamesm483mo ago

You ever run aluminum dry and wonder why people complain so much? I did a whole garage project with no coolant back in 2018 and it went smooth as butter with the right feeds and highspeed steel. Might be some folks are pushing their tools too hard or using blunt bits that just grab and stick.

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