Found an old shop manual that said to run coolant at 15% for aluminum, not 10%

I was cleaning out a cabinet at our shop in Dayton and found a binder from the 90s. It had a note from a past operator saying they always ran their coolant mix at 15% concentration for 6061, not the 10% we all use now. Tried it on a long run yesterday and the finish was way better, with less built-up edge on the tool. Has anyone else heard of running it a bit richer for aluminum jobs?

2 comments

2 Comments

robinson.quinn11d ago

Our old Haas service guy swore by 12 to 15 percent for aluminum. He said the extra lube helps with chip evacuation when you're pushing it. We bumped ours up years ago and it cut down on the smearing for sure. Just watch your sump for tramp oil, it seems to hold more at that mix.

the_ben11d ago

Honestly that tracks with what we've seen too. Running a richer mix really does help clear chips out of deep pockets. Makes total sense to keep an eye on the sump though.