From the circuit It seems that the motors require 24 V and on that basis I have bought drivers which range up to 42v

It is my intention to get all the motions functioning, utilising Mach 3 purely to provide jog inputs , after which I will go for a linux option to provide me with a functioning machine.
I am intending to use the existing power source (because it is there) It has outputs of 20v, and 9V which seem after rectification to yield 24v and 12v ( -ve) to the boards but the 12v rectifiers are integral in the board and I cant make out what its capacitor is . Will have to look more closely at it. Clearly I have to add a rectifier if I go this way.

I have a selection of BOBs, one with 0-10v output but only make / break switching at the relay.
I also Have a DIYCNC spindle board which might be suitable


Click image for larger version.  Name: spindle board.jpg  Views: 2189  Size: 175.9 KB  ID: 28974


I am hoping that this will give me the the Fwd rev outputs shown in Inee's diagrams but I am not clear on the relay connections shown.
RL1 and RL2 are incorporated in the board , so do I have to insert another relay into the circuit and could the above one fill this role .

Finally with respect to the spindle reversing relay I dont see any numbers on the base . Is there a convention here that I am unaware of ?
It has been working so I am guessing that it will continue to do so one I get the right signals to it .

Thanks again

John