Pictures of the Week                                            October 5, 2006

My first attempt at fitting the magneto drive to the alternator turned out to be a big failure.  After a couple of months getting my schedule to line up with a friend that had a lathe it turned out that the alternator drive hub was heat treated to a very high degree of hardness.  We were successful in machining down a carbide tool on the lathe and the alternator hub had not taken off even .001"!

After some head scratching I was able to anneal the hub using my acetylene torch.  It was a little tricky to get the whole hub to the right shade of dull cherry red.  To facilitate the slow cooling of the part I used a two pound coffee can upside down on the welding table over the hub.  I placed a huge pile of rags over the can to help insulate it and slow the cooling process.  This same process was used to anneal the magneto drive hub so that it could be machined.

How do you make this      Look like this    

The mounting flange had already been modified and it fits the engine.  The next step is to modify the drive hub of the alternator to allow the magneto drive hub to be welded to it.      The drawing can be found on sheet 3 at:  alt0001.htm

To machine the hole in the center of the magneto drive hub I used a 25mm hole saw in the drill press.  It took a couple of starts readjusting the clamp on the hub to get it centered but the result was quite good.  The hole is .002" from centered.  I'll chuck the hub in the lathe and clean it up to final fit.  The hole is .005" undersized so it should be no problem getting it cleaned up to the final diminution of 1.100".

I also made a trip to the local auto-electric rebuilding shop and purchased a bad rotor for the alternator for $10.  I took the commutater rings and fans off the rotor so that it can be used as a mounting tool to chuck the alternator hub in the lathe.

Hopefully this weekend I will have a complete alternator with magneto drive.

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