Pocket size layout guide for holes.
 

I do lots of hole layout at work in steel pipes and i can remember the holes sizes but i can't set my dividers from memory. So i like everyone else hold my dividers up to a tape measure or use a rule to set them. Then i made this aluminum plate with a center and the rest of the hole sizes layed out in a semi circle. So now i just stick one leg of the dividers in the center punch mark and the other leg in the size i want. Simple enough. Sure knocked off a bunch of time when you have to layout 25 holes all different sizes. I even have room for sizes i might run across sometime Standard size fittings on the right and 3000# fittings on the left...Bob