EZTrak spindle sense

I'm preparing to fit an auxialary air spindle to the Bridgeport EZTrak
DX cnc mill, and need to figure out a way to make the control run with
the main spindle turned off. After looking over the circuit diagrams,
it seems it would be a simple matter to add a switch in parallel with
the contacts on the spindle forward/reverse relays which signal the
computer that the spindle is running. I'll probably make this same
switch activate a solenoid valve to turn on the air to the high speed
spindle.

My question: anyone done this? Anyone come up with another method,
that perhaps doesn't require drilling holes in the electronics
enclosure to run new wires?

Thanks,

Chris

--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
http://www.mdc.net/~stratton
(617) 629-9830 home (temporary), 253-2606 MIT