Thanks Peter, that is the one I am thinking of where the pins can be calibrated. The plastic gauge for visual centre I set using feeler gauges and it came out spot on.
I'm still around, but not as active online. Keep thinking of doing shorts now that YouTube supports those. Have an ongoing list of short topics but then I think we all have lists to do 'real soon now'. Then there are guys like Peter Parfitt poking at me... [big grin]