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Monthly Archives: July 2015

Vincent’s Gran Sport deralier repair

The last month has seen a variety of work in the workshop. I started out with a visit from Vincent and an odd request. Vincent had recently taken possession of his fathers racing bike and had it shipped out to Australia from Ireland. He had discovered that the Campagnolo Gran Sport rear deralier had a broken stop where it comes up against the hanger. You know that little knob that stops the thing pivoting all the way forward. Early Gran Sports are bronze with chrome plating. Vincent knew that he could buy another one but wanted to attempt a repair for obvious personal reasons. I agreed to try. I filed of what was left of the broken part and turned up a post to be able to hold the deralier square in the milling machine. I drilled and tapped a 6mm hole in the right spot and then turned down an 6mm cap screw so that it would just clear the hanger as it rotated. I cut off the cap screw to the right length. Viola

Gran Sport deralier

Gran Sport deralier

Gran Sport broken tab

Gran Sport broken tab

Gran Sport deralier post

Gran Sport deralier post

Gran Sport Repair

Gran Sport Repair

Then I had a return visit from my artist friend Bundit with another request for some single speed badness

Bundits Single Speed badness

Bundits Single Speed badness

Bundits new brake bridge

Bundits new brake bridge

Finally and not yet complete Justin dropped around his Cecil Walker to get a set of canti pivots brazed on to it and to do do a slight repair on the seat tube.

Justins canti pivots

Justins canti pivots

The setup for Justin's rear canti pivots

The setup for Justin’s rear canti pivots

I am always learning something. I had taken it for granted that all rear deralier pivot bolts were M10 x 1.0. Doing Vincent’s gran sport I discovered that early Campagnolo used 26tpi (threads per inch). Nearly but not quite the same

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Posted by on July 31, 2015 in Uncategorized