I'm wiring a Leviton 5374 Welder Receptacle (2 pole, 3 wire, 50 Amp, 250 Volt, grounding). If I use a 3 wire with ground can i just ignore the white (neutral) wire. In other words, is it ok to wire the red and black wires as the hots (to make 220) and the green wire as ground with no nuetral?
That's exactly how it's done. Cap off the white wire so it cannot touch anything else including the metal box (if the box is indeed metal....) Just twist a wirenut on the end, no need to strip the insulation off.