Hello Humvee67, the first thing that you might look into is the manufacturers tag on the welding machine that you have, even though it is a Snap-on machine, it is likely that it was built by Miller, Lincoln, Hobart, Esab, or someone else. There is likely someone out there who knows specifically who builds Snap-on's machines for them. In any case what usually counts is the type of voltage that is required to operate the drive motor in the spool gun and the type of switching that is provided by the gun to activate the output of the welding machine to provide the welding power when the trigger is depressed on the spool gun. On most of the spool guns the gas is actually controlled by a manual valve within the spool gun so that isn't an issue. Oddly enough I have a Thermal Arc multi-process inverter that I plug a Miller 30A spool gun into and it is a direct connection and operates perfectly. So you are probably on the right track thinking that a less expensive spool gun can be had that will work with the Snap-on machine. Good luck and Regards, aevald