I saw Step and Dir on JP26 and assumed that I could use those points to drive my spindle.
Oops my mistake. I was thinking JP33. JP26 has Step/Dir inputs (not outputs)
So back to an earlier response from you when I said I wanted to control a spindle you suggested "You might also use the IO on KStep which is fully isolated." Where/how would I do this? or should I just leave well enough alone and stick with JP5 (I/O 39,40 & 41)?
I don't recall that. But KStep has 2 isolated Relay Driver outputs for enabling Spindle Enables for CW and CCW. Also an isolated 0-10V Analog Output to control Speed. But if you want to use the C6 board for that it is fine.