Home Builders: How to make a frame leg jig


Note: I plan to use hose clamps instead of C-clamps as I found it tough to setup the C-clamps.

i opened this thread all ready for a heart chortle thinking you meant jig as in the irish dance.

It is nice though. Very nice. i am nothing of a DIY guy but i shall bump it up for others.

I guess you would have to be sure that your plate was perfectly square to the square tube. But if your uni leg is tapered then the bearing holder would not be true hmmmmm?

Looks like he’s holding the square tube with a right-angled magnetic thingy so that should be pretty close at least in one plain, but it could certainly be off sideways (or forward/back with respect to the frame leg). And if the leg is tapered…
Come to think of it, the legs of uni frames aren’t usually parallel anyway are they? Certainly on my muni frame the legs converge in quite a bit from the crown to the bearings and my coker frame is the opposite (splays out).
Seems like it would be better to make the frame minus bearing holders, put the bearing holders on the hub then offer it up to the frame and weld it.

But I’ve never done it myself, so I may be talking poo. The fit of those bearing holders is so vague anyway that it probably doesn’t matter that much - would be more important with machined bearing holders I would imagine.



I have found spring clamps like these to be real handy when clamping pieces in place for welding.

It only takes one hand to open the clamp, leaving the other hand free to hold the work piece straight.

This is the jig that I made up to hold the ends square while I weld the Crazy Arm Cranks together.

I just eyeballed the square tube. Since i use rubber between the leg and support post there is a lot of flexability. Its really just something for the clamps to clamp to, I can move the leg back and forth to addjust its position on the bearing holder.

i personally use magnots and balancing but i night try that

cool idea did you weld that frame with a tig welder? and do you now the dimesions on the oval tubing. thanks

where did you get that oval tube from ?

Its not oval, its streamline.

well where did you get that

an airplane.


didn’t realize that was stream line.
got a picture of the completed deal?

Were you at naucc? Spencer has one of my frames, its got streamline tubing. Pay no attention to the offset seat tube, I don’t do that anymore I sware.