ON Topic! Metal Working Coolants

would be something on topic before Thanksgiving.

thanks Steve!

yay! an on topic post! :D

just wish there would be more of these..

Super-excellent, altho plowing through this thing is going to be a bear, albeit an informative one. Just wish their summary woulda been a real summary, not this "more research/study is needed" crap.

I'm wondering if an "empirical test" for coolant integrity could be performed, such as a standard bar of material, with a standard em, taking a standard cut. Mebbe even a cutter of deliberately soft HSS (a sacrificial em, so to speak), so that wear might be quickly assessed.

A number of parameters could be assessed: Wear on the sacrificial tool, finish on the standard/reference material, and perhaps even such things as temperature rise in the material -- the lower the rise, the better, presumably. A series of these cuts could be saved, so trends could be observed.

I *never* change my coolant, not just because ahma hack machinist, but because I lose so much coolant that in a cupla months (one of their rec'd change intervals), I figger I've been through the whole reservoir anyway.

But, it does raise inneresting points, such as micro-chips suspended in the coolant, and filtration. I used to put a goodly amount of cheesecloth between the effluent troughs and the reservoir screens, and indeed this trapped a lot of fine stuff.

In principle, fine particles, like grinding dust, could be quite the abrasive, shortening tool life.

BUT, if you weren't keeping an eye on said cheesecloth, it would clog up and flood the floor in no time. Stopped using it eventually, and haven't really felt anything gritty in the coolant -- if micro chips/dust can be felt.

Also don't use a refractometer, go by feel -- whole milk/half'n'half (OK), vs. skim milk (too thin).

I also figgered mixed in tramp oil might help the coolant processes.... but they seem to think it interferes.

I also use a fish-tank aerator, suggested some time ago by someone here. Altho it doesn't seem to be bubbling the way it used to. Seems to quite help the funkyness factor.

I'd still like to know the story with mixing different coolants!

If they are both petroleum based water soluble cutting fluids then likely you won't have a problem.