Another EDM Approach

Just musing, I'm out of my depth here....

I'm also interested in EDM. I had concluded, before the recent posts,
that useable home EDM was not feasible. Seeing the recent posts I'm
not so sure. How about simplifying the proposed circuitry by
offloading most of the control to a PC. The parallel port already
controls my Z axis using a step and direction pin. Could the third
pin be tied to a one shot circuit to fire the pulse? A trim pot with
knob on the one shot circuit could manually control the pulse length.
Determining optimal operation (no spark, just right, short) seems
like a much harder task. It could be done if the EDM interface board
could post the operational status using some of the remaining
parallel port pins. The software to drive such an arrangement would
be trivial.

Roger