Hi John,
I can really recommend 'LocLine', don't be tempted to get the cheap far eastern equivalent. Apart from the non interchangeability, I have both so speaking from experience, the cheap ones tend to leak from many of the joints, whereas Locline does not.
Rotagrip do reasonably priced kits on ebay, either 1/4", 1/2" and 3/4", I use 1/2" both on the miller and on the lathe, you get several sized nozzles and taper pipe-screw fittings as well.
I have both machines coupled up to the same coolant system, the pump is of the central heating circulating type, based in the lathe motor housing, it the feeds the miller off the lathe feed, the miller drains into the lathe tray, to return to the lathe tank.
A few pics will illustrate.....
Chris