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Dynamo Insulation Bobbins
The Lucas C35A dynamos have a bobbin that fits over a peg adjacent to each brush holder to insulate the brush spring and give it tension. They seem to be made out of some early 1930's version of plastic and are very delicate. I've had two disintegrate in the last 12 months, the latest this week. 

I imagine they could be replaced with a short length of windscreen washer tube but that, in time, I imagine the tail of the brush spring would work its way through the material. I have some suitable Acetal  rod and could turn up some copies in a more modern and robust material but before I do, anyone got any other suggestions of what to use. 

Steve, I made some out of a rod of nylon- as good or better than the originals.
Thanks, Bob. Acetal rod is similar to nylon rod so should do the job.

I made my replacements - when I found cracks in the originals - from Paxoline, what ever you use, it needs to be heat proof, plastic could melt, the inside of a dynamo can get warm.

Made a set in Acetel. Took no time at all and dynamo now sorted. If I was to make a form tool more could be knocked out easily but I don't have the need.

Originals are in Bakelite so make no wonder they fall to bits 90 years on.

Never had a heat problem with replacements I have made from Acetal rod so you should be good to go Steve. It would be good to see our suppliers stock these as there is an increasing need for them these days.
Black Art Enthusiast 
I bought some of these just this week for the same job. Nylon will be tougher than screen washer tubing.

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