"William G Darby" wrote in message ...
I just bought ten gallons of ISO 10 hydraulic fluid to try as flood coolant.
I am just now draining out the rancid water soluble and drying out the sump
before I fill it with the ISO 10. There are two drains to my sump and I am
going to block both so that the way oil cannot get to the sump and mix with
the ISO 10. It (the way oil off of the X,Y and Z slides) will collect in
the trough around the base and I will have to keep it cleaned out. I have an
enclosed table and it is possible for me to drain the ISO 10 directly to
the sump via a holding strainer to allow the rough filtering out of cuttings
before they find their way to the sump.

I know that one of the guys already uses hydraulic fluid as a coolant so I
am sure it will work but I would invite any comment on what I'm doing, that
may pre warn me of potential problems or any pro or con comments.

There are pure oil "metalworking fluids" like Mobil Omicron and Mobil
Omega that have proper cutting-oil properties. According to the sheet
Omicron also claims application as a hydraulic oil.

I use Omicron for flood coolant on my lathe because I am not willing
to subject the lathe to anything else. It'll get used for a week and
then may sit under its bedsheet for months. Likewise my old K&T mill
because it is "leaky" and the soluble gets into the gear cases and
make a mess. The Omicron is more useful for clearing chips in an
awkward cut than as a coolant per se because it smokes at a low
temperature. In my experience the chip clearing is more useful
anyway as it is the key to getting a predictable finish.

I am strictly an amateur here so apply your own advice filter...

Bob