Monday, February 25, 2008

Alignment Plate is ready.

The alignment plate is ready to go, and bike #1 is in progress. Here's the bottom bracket post for the plate, in the background you can see the shims and depth micrometer. I decided to use a setup like this because I can adjust the height of the shell depending on how much material I face off during machining. Once the bottom bracket is perfectly centered the rest of the system is pretty straight forward.

Here you can see the rest of the components of the plate. The long bar goes through the head tube and has two reversible cup for 1 1/8" and 1" head tubes. The blocks it's resting on are set to check for twist and height. I had a 27.2mm stub made and mounted on the angle block for the seat tube. this way if I do an over sized seat tube I just need a larger stub made and can mount them interchangeably.

Finally, for checking the rear spacing, I've got the cool surface gauge I found on Ebay and a dial indicator that a friend rebuilt for me. The block at right has steps for 120, 130, 135, and 140 spacing. All I do is set the indicator at the desired height, check the lower dropout face, and use a caliper to set the final spacing. Works nice.

I also put together some lug mandrels for holding the lugs during carving and grinding. They're basically a piece of tubing with a wedge at the business end attached to a threaded rod that I can tighten on the other end. Took a while to grind the wedge just right, but I used them today and so far, so good.

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