At the shows we run a vacuum pump piped up as a compressor to blow air onto the tool with a drop of cutting fluid bled in as we are usually cutting steel or alloy.
These run continuous from 10am until 5:00 pm and even though they get quite warm they don't give ant trouble.

Add to this they are 3 phase units rewired in delta with a capacitor across the dead phase so we can run them on single phase.