Question about an old timer's advice on coolant ratios

My foreman at the Milwaukee shop said to always run a 10:1 mix for aluminum, but after a month of constant reaming issues, I switched to 8:1 and the finish cleared right up.

3 comments

3 Comments

taylor_young22d ago

To be fair though, 10:1 isn't really "leaner" for aluminum... it's actually more concentrated coolant than 8:1 since it has more water. Richer mix means more water, not more coolant, so going from 10:1 to 8:1 actually gives you more lubrication and heat transfer. Just a small mix-up in terms but the point still stands about the old rules needing updates.

margaret_kim131mo ago

Wait, you had the same exact problem? I always thought running leaner coolant was better for aluminum too, but I burned up two expensive end mills before I tried a richer mix. The difference in how the chips cleared out was crazy, it just worked.

quinn_wood1mo ago

Your foreman is stuck in the old ways! I had the exact same problem with 10:1 on a big aluminum job last year. Switched to a richer mix and it was like night and day for chip evacuation. Some of those old rules just don't hold up with modern tooling and feeds.