Machinery's Handbook (25th) has X-Y coordinate tables for bolt
circles, up to 28 holes. Their numbers are for a circle diameter of 1.
Multiply by whatever size you circle is, and go.

Chris
The correct way to punctuate a sentence that starts: "Of course it is none of my
business but--" is to place a period after the word "but." Don't use excessive force
in supplying such moron with a period. Cutting his throat is only a momentary
pleasure and is bound to get you talked about.