Frame Alignment Jig

I pretty much had all the pieces I needed for the frame, all be it in rough form. My next consideration was how to fix them all together so the frame was straight, true and the wheels were aligned - so I had to make another jig. From my CAD drawings I worked out the positions of the front and rear axle, the bottom bracket and the angle of the downtube. Using MDF and pieces of wood I made a jig. The rear wheel axle was 130mm wide, so I made the rear axle jig appropriately so that I could bend the chain stays to fit. I bought a pair of carbon forks that were the length and rake that I wanted. Using clamps I loosely put everything together without glue to see how it was looking and make the necessary tweaks.

I bought short sections of metal insert for the headtube, settube and bottom bracket. I drilled a few holes in these, not particularly to save weight, but as I thought some epoxy 'oozing' through them might help give a strong 'key'. (I forgot to take pics)

The rear seat stay still has the outer brown oak layer missing but shows the route for the cable. I made some temporary MDF dropouts just for alignment purposes.

bike frame in jig


© Christopher Thompson