Sunday, April 15, 2007

Small .050 vent holes in the yoke were an after thought.

Trimming the chainstays to length. This isn't that critical as my yoke design allows for lots of slop.

Checking to make sure the new block/dummy axle is square.

Here is my scabbed on block to extend my dummy axle.

I ran into a couple of snags on the frame jig. This is really the first complete bike I've built on this jig. First off, it isn't adjustable enough. If you build your own jig, make sure it can go well beyond any norms for geometry and size. This bike has such a low BB, that the headtube adjustment is maxed out and the dropout is well out of range. Another issue was the headtube cups. The originals were stepped. This made setup easier and more accurate, but when the headtube ovalized slightly during brazing, the cup was stuck. Combined with the cooled flux, it was a chore to get it out. Tapered cones are the answer. I will still use the other ones where I can since they are easier. Another lesson I learned is to allow more slop. My old headtube cups had .001 of clearance on the ID. This would have been plenty if it hadn't gotten hot. The new ones have .003. Same with the BB post.

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