I do my best work when I’m comfortable, and I’m usually most comfortable when I’m seated. For some time, I’ve wanted a stool with certain features — something that’s low, rolls easily over small obstacles, and has a storage tray. I recently got a new Millermatic® 142 welder, which I’ll use for building this project.
My stool will have three legs, so it will be stable on any surface, and I’ll use 3-inch casters, which can easily roll over small obstructions. I found a 19-inch cooking pan, which was ideal for the tray, and I was ready to start the design.
With a little research, I found casters that mount with an expanding stem that fits inside a 1 ½-inch tube. I positioned the casters close to the edge of the pan and measured the distance between them. I made a fixture to hold the caster mounting tubes in the proper location and support the 2 ½-inch tube that will hold the seat. I made the fixture from ¾-inch plywood, covered with sheet metal to protect it from heat and denting. I used a piece of ¾-inch pipe as a column to hold the seat tube, and a standard pipe flange holds it vertically on my fixture.
I drilled holes in the fixture at the caster centers and inserted 1/2 -inch bolts. Tightening these bolts will expand the caster arbors, gripping the mounting tubes and pulling them snugly against the fixture. I made some MDF sleeves that fit inside the seat tube and slip over the vertical pipe. A hose clamp tightened on this pipe allows me to position the seat tube at any height.
With the caster and seat tubes located, I was ready to design the legs that join them.