safety gap setup

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: mileswaldron@xxxxxxxxxxx 

Terry,

I have ordered the parts from DigiKey for a 15KV Terry Filter. I will 
probably be too excited to wait for the parts to get here before I 
start up my new coil. I am either going to use a vacuum gap, an async 
rotary, or a fan cooled multigap. That is my current quandry, with 
all the different motors and fittings and things all laying around, I 
am waiting for something to call out to me. However, I want to at 
least put a safety gap onto the circuit before I power it up. At 15KV 
I understand that I need to keep my max spark gap < 1/4 of an inch. 
Is this a good rule of thumb? Also, how do I adjust the distance for 
each leg of the safety gap for best protection? I have a pair of 
adjustable angle brackets with steel spheres (well - steel sphere 
like cabinet doorknobs) that I can use. Would a sharp point be 
better? How close together should the safety gap be?

Sincerely,

Miles Waldron