Coolant flow

I use a little giant condensate pump, maybe half a gallon per minute, I'd guess, but I never let it deliver anything like that. I use the smallest Loc-Line nozzle. I have a retrofitted manual Bridgeport with no factory shields, and the coolant return is through the T-slots and the galleys at the end of the table. That limits the amount of coolant I can pour on the work. Also, getting just the right amount of coolant makes a big difference. Too much, and it runs up the cutter onto the spindle nose and starts spraying all over the shop. I have a throttling valve which is actually cobbled from the valves that go under a sink to turn off the water to the main sink faucet. I have this mounted to the little ear on the right side of a Bridgeport head, it makes a really convenient place to attach the Loc-Line tube.

For a benchtop machine, I'd think 1/10th gallon per minute might work out about right. it depends a bit on whether you just want cooling, or want to use the coolant spray to shoot the chips away. The latter insures a huge mess and you will need complete guards.

Jon

The best flow varies with what you are doing. For the lathe, I built a system pot of a manifold, a bunch of cheap needle valves (one to a nozzle port), plus a feedline ball valve (to turn the flow on and off without disturbing the needle-valve adjustments). It works well, but you still need splash shields to contain the mess.

As for the mill, two nozzles would be best, on opposite sides to the cutter, but again a needle valve is useful, as quarter-turn valves are hard to adjust precisely.

Joe Gwinn