On Fri, 13 May 2005 22:38:49 +0200, Jon Haugsand wrote:

* R. H.
Don's guess is correct, the coil is made from varnish coated magnet wire,
each of the two axles has had half of this insulating varnish scraped off,
making them function as primitive commutators. I tried Carl's idea of
scraping off all of the varnish and got the same results he did, it still
worked.

If anybody wants to make one, it works best with very thin wire.

Amazing! This /is/ something to impress today's kids with, because
they are used to that you have to buy things from the computer store
or whatever. But here you can pretend to just find some wire, a used
battery and so on. Need to try this. The wire is something I don't
have in-house, so I'll need to figure out which store stocks such
items.

In the US, Radio Shack. They sell a pack of 3 sizes on small spools.
It's called "magnet wire", just in case nobody's mentioned that yet.
http://www.radioshack.com/search.asp...age1.y=0&SRC=1
278-1345

Cheers!
Rich