Adjustable Capacitor Tesla Coil Tuner
Designed for higher frequency coils and flat spiral Pancake Coils




Top section uses 3500V 8mA transformer 

Bottom section uses 5000V 8-10mA transformer



Depending on which of the three circular hole pattern rows are used as positive stops in adjusting the spark gap, the following increments can be had:
1 / (40 tpi) x 30 holes = 1 / 1200" increments
1 / (40 tpi) x 120 holes = 1 / 4800" increments
1 / (40 tpi) x 360 holes = 1 / 14400" increments





Keyed switches select 3500 or 5000V transformer and cap arrangement





Data drawer




UPDATE:

Unfortunately the black wood is conductive!!
So now we have:




Single units.  Transformer mounted below!










(C) Jeff Behary, 2011