After building the jig, I needed somewhere to mount the damn thing, since it weighs about 100 pounds. This part actually took quite a bit of thinking before I was ready to commit to a design. My design parameters were:
-Mounted to my welding bench so that it didn’t move much, but could still be rolled around if I needed it elsewhere.
-To rotate 360° to give me the most possible access when welding while in the fixture.
-To swing left and right so that I could get behind both the front and rear of the fixture for welding, and also so that I can swing the whole thing to the left and out of my way when I need to use the welding bench for other things.
-To raise up and down by quite a bit so that I can raise it for fitting all the tubes, and lower it to weld in my chair.
I decided to use bronze bushings to go between the two pieces of steel pipe. This gave me a nice smooth rotation, and also conducts electricity so that I don’t have to use a ground clamp on the fixture.