Designed and built by Felix Slothower blueglass-logo

Welding Jig

Designed and built a welding jig for the UCI Frame Building club


During my junior year at UCI, my friend and I started up a small frame building club, following our love for riding bicycles. We had never fabricated our own frames before, or done any serious welding for that matter. As we were starting from ground zero, our first project was to design and manufacture a welding jig.

Revision 1

In order to weld a bicycle frame together it is necessary to fixture the tubes in a consistent and calculated fashion. Commercially available welding jigs were outside of our clubs budget so designing our own was the only option. A good welding jig is easy to set and relatively accurate (compromising on dimensional accuracy was a major theme throughout the design process). Our first iteration was over engineered, and it took us longer than I would care to admit for us to realize that.

front isometric

rev1 would require a lot of machining, some of which was probably overly difficult and complicated. But we were determined to push forward since we desperately needed a welding jig. The school year was coming to an end and we wanted something to show for our first year as a club. Machining had begun on the arms holding the head-tube and seat-tube in place. Fortunately, we didn't get much more done and had to hang the project over summer, giving us some time to become less attached to this revision.

Revision 2

When we looked at it again in fall we did a sort of informal design review of rev1 and came up with a much more simplified design. Since we already had some of the parts machined we made sure to preserve these in our next revision. By comparing both drawings it should be clear how much simpler the manufacturing would be. This was thanks to taking advantage of more OTS parts used for 8020 extrusions.

front isometric

This was our last revision that eventually got manufactured. Using a mix of tools in our garage and the machine shop on campus we were able to make quick work of it. We were also pretty excited once it was finished; hence the fancy pictures.

final build (full) wrenching on the jig

rear axle closeup headshot

Designed and built by Felix Slothower