Hi Terry,
I like the logic of your system for testing Real Bull electrics, though it might be as well to include a warning that lathes originating from Sieg may differ. That is offered as a constructive comment, rather than criticism.
Near the end, you say:
"
The function of terminals 9-10 & 11-12 control connections to the daughter board and potentiometer needs further investigation , they almost certainly are an integral part of the switching / interlock and speed reduction when Rev is selected. As previously stated no circuit diagram is as yet available for the daughter-board so further research is necessary."
There is a schematic of the daughter/auxillary board in the files of the Yahoo 7x12 Minilathe Group <
http://groups.yahoo.com/group/7x12minilathe/ > , but you have to join to see it. However, Pat (the retired electronics engineer who drew it up) kindly allowed me to reproduce it on this webpage; it's at the bottom:
<
http://andysmachines.weebly.com/variable-speed-controls.html >
Not having a Real Bull lathe myself, I haven't bothered to trace how the motor is slowed down when run in reverse, but R4 (the lonely-looking resistor at the top left) is brought into the speed control pot circuit when reverse (or forward; I'm not sure) is selected.
Though you may of course make whatever use you wish of the diagram for your research, I don't think it would be fair on Pat to reproduce it on your website. It would be better to refer folk to the 7x12 Group or to my web page as above.
Hope this helps with your analysis of the wiring.
Andy