Many thanks John,

I've been ignoring them until now...but I need replicability (in other words, I'm aiming towards a goal, where I can easily churn some simple identical parts out in short order).

Parking the replicability for a moment, I have a fairly imminent need to be able to mill a tiny pocket out of the end of some plastic threaded rod (I don't have a lathe) ..one way I've considered tackling this 'how to' problem is via a home switch. Basically, if I can start my spindle/tool from an exact known location everytime, then I could for example have the tool drill a whole in my cnc's base plate with the tool - self harming for CNCs! (actually probably some waste material clamped to the base plate!)....I can then tap thIS hole & insert/twiste my threaded rod into it...becaUse the cnc tool drilled the hole in the first place, it knows the exact centre...but the tool would need to start out from the same position each time (hence the home switch!).

It's got to the stage where I can see quite a use for starting the tool in a known position each & every time.