Hope you can help me here guys. I need to measure then drill 2 mounting holes in a plate to mount a small electric motor centrally to the existing hole. The boss is not centre and despite trying to make templates etc I cannot get it right. I've been told I need geometry to work out the positions but have to admit in my dark and very distant pass we never learnt any. I've attached a photo showing the plate with my poor attempt and the motor housing in the hope you can explain to me in single syllables how to go about it. You'll see beneath the brief, and for me, confusing explanation of what I should do.
The aim is to find the positions relative to each other, find the PCD of the circle the fixing holes are on, measure from the inside of one hole to the the OD making sure you do it going through the center line of the housing, then measure one of the holes, half that figure and add to the first measurement that will give you the hole center from the edge, from that you can define the PCD.