NO contest IMO the W/C spindle wins hands down Micheal.!! . . . Unfortunatly it's one of them untill you've used one you'll never now how good they are things.!

Don't need Rads fans etc a simple submersible pump (£15 Ebay 24V 7mtr head height) into a sealed container of decent qty 20-25lt is all thats needed.

Some one asked me a while ago how long the spindle would run without coolant and because it's not something I've done purposely for more than a few minutes couldn't truely give a definative answer other than 5 minutes or so!!. . . .Well as of a week or so ago this changed.?
Now this is the part where I fezz up to doing an embarrissing numpty trick. . . . . . I forgot to tighten the pipe clip on the pump after fitting a new pump resulting in it falling off in the tank. . . . The machine had been cutting Aluminum for nearly 2hours without coolant.:surprised:

The only reason I spotted the problem was because when the job stopped I didn't hear the water back drain into the tank like normal pricking my attention.! . . Now you can imagine my shock horror when I opened the top and realised it had just been cutting 2 hours without water.!
My first instinct was to clasp the spindle expecting it to be red hot and it wasn't.!!. . Yes It was lot warmer than normal but no way would I discribe it as any where near hot and absolutly in no way did it affect cutting or show in loss of power or even change sound.
(This said the temp in the shop was bloody freezing so this would help very very very very slightly.!)

So my point confessing this embarrising cock up is to point out these spindles are very robust regards cooling and even when run without coolant for prelonged periods they won't kill them selfs. So thermostats etc are not really needed or would have even helped in a situation like this unless monitered by software to shut down if the flow stops. . . . . Really a flow meter connected to an estop would be far more usefull. Obviously I'm not recommending or saying it's ok to run these spindles dry in anyway but they won't die in minutes thats for sure.

So now my Answer to the quastion has changed from 2 minutes to 2 hours.!!. . . . . But I don't plan on testing this any further.:lol:

Save the S-Pid money and go straight to WC using the simple cheap approach is my vote.!