Hi Ed, I am almost expert at revolving plug type fixings now :0)

I do like this mcad approach below, kinda what I explained before. ..
It's its from Ironcad, oops dont like its price...

it's like create part, save it in 'library' (or object layer¿), apply holes to selected surface / hole position(s)...

This is sort of tidy interface works but even a list of variables would be workable and cover basic hole types.



Well documented here:
http://www.ironcad.it/en/manuale/holes

Just ideas or doable?

Regards

Stefano