Thanks for the info Dean. I am a bit cautious of turning power off to spindles after having the end of my right index finger chewed off by a facing cutter. I don't want to lose any more finger(s) or spend time in A&E being sewn back together. Given a choice between a snapped cutter or a finger, what would you choose ?

Eurikain beat me to the BoB info, but it is the type that has speed control and you can use the same pin as the B axis step for controlling an onboard relay to switch the spindle On/Off.
Cheers,
The Fat One