[TCML] rotary gap disk

[Jon Danniken]

----- Original Message ----- 
From: <jhowson4 at comcast.net>

> Hey, I am making a sync rotary gap and I was wondering what
> material should be used for the disk?  I was thinking acrylic but
> wasnt sure if it was too brittle to machine with my limited skills.

I was in a similar situation as yourself, having only a small drill press 
and a router, so I made my disk from polycarbonate (lexan).  I used a 12" 
diameter wheel, 3/8" thick, with a shaft arbor adaptor in the middle; the 
whole thing is driven by an induction motor modified to run at 1800RPM. 
I've run this at about 1.5kVA, and after a minute runtime the flying 
electrodes are still room temperature.

The fixed electrodes get really hot though, so much so that I had to rebuild 
them into chunks of aluminum for heat sinking, but the speed at which the 
moving electrodes travel allows them to cool themselves off.  All electrodes 
are solid tungsten (moving were made from 1/8" tungsten rod for TIG welding, 
fixed are 3/8" tungsten rod from a group buy).

There's a few pics of the setup here:
http://teslacoils.home.comcast.net/gap/Gap.html

Good luck!

Jon