If welders were meant to plug into drier outlets they'd come with drier plugs on them.
If Broncos were meant to have D60's under them, they'd come with them from the factory :twak
I gotta ask what you're thinking asking for electrical advice on a 4x4 site?
Ummm because most 4x4 enthusiasts have welders and thousands of them across the nation operate their welders from a drier outlet, and it's perfectly safe :twak (there's even mention of doing this exact thing in most welding books)
Common is not ground at all!
I went to both my dad's and my mom's houses and yanked the access panels off and studied the wiring. In fact, the bare copper grounds and white insulated neutrals for 110v and 220v DO go to the same ground bus, so they are all electrically equal. This was already a given since we know that if they were carrying different voltages, there would be a huge problem with the plug on the drier shorting the white and bare wires together at the L-shaped pin of the receptacle.
Anyway, I'm fairly confident in my design and I went and got the parts for the extension cord today. They are as follows:
6 ft long replacement drier cord with 10-3 wire: $8.99
50 amp receptacle for welder end of the cord: $12.49
15 ft of 10-3 flexible water resistant stranded wire: $19.65
That's a pretty expensive extension cord, but if you're not too far from your outlet you can save $20 by not getting the 15 ft of wire and hooking the drier cable straight to the welder receptacle. I would've done that but I might want to weld in the driveway if something is on my truck and can't be removed, so between the 6 ft drier cord, 15 ft wire, welder power cord, and welder stinger cables, there should be plenty of reach. I feel that this is plenty beefy since the cable shown in my welding book is made of 12-3 wire and is actually a 50 amp patch cable, so it could potentially see 50 amps while mine will never see more than 30, being on a 30 amp drier breaker.