Calstar- Hope I can make this happen- here is pic of "fixture."



I want to make it clear- this is by no means a recommended way to do it. When I built my first frame I was looking for a way to hold the tubes so they would be somewhat in plane, and I could compare them to the drawings. I never intended to build a "jig," nor did I intend to buy one. I just needed something that would hold the tubes tight to the plan. Once the frame sizing and geometry were on paper... in my usual fashion I scrounged around the shop for stuff I had that would serve the purpose.

I wanted something that was adjustable to a degree, and was flat enough overall that I could use it to measure basic (front triangle) alignment once the tube were clamped in. It's probably not obvious from the pic but I knew going in that bottom bracket alignment, and head tube alignment weren't going to be doable in the same manner as traditional jigs. So... I cheated.

I used a base of MDF small enough so I could see the important points of the original drawing. I don't know if the base is obvious in the pic or not. Since I desired some method for adjustment, and needed a point to clamp the tube to, I used a couple (well actually three) of frames from wood working clamps (think T-slots). These were screwed to the base. I cut some angle and slotted the attaching holes so that when fitted to the (T-slots) I had some adjustment. The angle provides the surface to clamp the tube to, aqnd the toggle clamps you see hold the tubes to the angle.

There is a method for holding the BB. It's just a piece of 1/4" flat attached to the base. I needed to secure the BB (obviously) and provide for a square atachment. To center the BB (or the seat tube on the BB) I use a couple of threaded blanks screwed into the shell to adjust it's height.


As I mentioned before, the head tube joint fitting is last- but not least. I didn't have the desire or (wherewithall) to to locate the HT relative to the other tubes by the traditional "cone method." So... I reasoned that if my miters were correct (phasing. angles, etc) I could pop the head tube in last. It actually doesn't work out too bad. I tack the ST-BB-DT and TT (all the miters have been made to accept the HT) and secure it in the clamps. Then alignment checks are made to insure all tubes are centered and in plane.

Next the finshed head tube is held to the DT-HT joint by the crude clamp you see in the pic. Hopefully the mitres, offset, and angles are correct. It's easy to measure at this stage. If it's off slightly- you have the DT-TT where you want them so one can adjust them with a file easily (you ain't gotta a lotta room for error or the lengths will change.) Once lined up- tack 'em and go.

I only intended to build one frame when I devised this method for holding things. It has some limitations but actually works quite well, and the frame off will be #14. Plus... I might have only $15-20 in it, at most.


I by no means present this as a/the way to do it. I only put this out there to show you can get it done without spending big bucks- for us home hobbyist types of course. If I were doing it commercially I'd figure out a system that was a bit quicker.