Welding 1" Nuts together Tips


I am trying to build the Fireball DIY vise but having a hard time keeping the two nuts in line after i start tig welding. Your video made it look like you just put it in a vise and welded it up.

I tried at 100 amps and 120 amps.

First attempt the nuts were touching but still able to spin and tig welded it on the threaded rod. I tried cooling the bolt in water to help after the weld but I had to really force it to come off, even after it was completely cooled. The threads on the bolt were heat affected (messed up) and the 1" bolt changed colors.

The second attempt i left a bit of a gap and tried tacking it on the bolt and then removing it and welding it on the table. When it cooled it was worse then the first attempt.

Any tips or tricks to keeping two nuts spinning freely? Probably going to buy a 1" tap but wanted to see if there was a way to keep them spinning freely or best practices for future projects or if the tap doesn’t work out.

I’ve done tests after the vise video was made and discovered the long thread really doesn’t help thread damage much. The first few threads of the nut do most of the work. So 1 nut will probably be fine. As far as joining 2 together I don’t remember how I got them to work. I think I pre loaded them in opposite directions? Or I cheated and ran a tap through them. You can purchase extended nuts. They call them couplings. Te-Co Coupling Nut, 1"-8, Steel, Grade 5, Black Oxide, 2-1/2 in Lg, 1-5/8 in Hex Wd 41509 | Zoro


I forget the statistics, but when they test fastener pull out strength the majority of the force is in the first thread, and the 4th thread doesn’t do much.

Edit: see below

I was always under the impression that the rule of thumb was 6 threads deep and the thread interface was as strong as the fastener (as in you’d snap the bolt, not strip the threads if you overtorque it).

That varies a bit with fine VS coarse threads and other screw profiles, as the root diameter is what determines the failure strength of the screw.

@mRhAnKbOt I think you’re right, and it seems that’s the general design on the thickness of nuts.