Woodpeckers Shelf Pin Jig 

You don't need a store-bought jig to drill shelf holes in new panels _BEFORE_ they're assembled into cabinets. The hard thing is to do retrofit adjustable shelf holes into a cabinet that's already assembled & installed. Good luck getting these little clamp things to work in that situation.

The best shelf pin jig I've seen so far!

The only thing that would make this better would be an adjustment for different thicknesses of wood. Perhaps you could design the "u" shaped red piece to have an up and down movement to accommodate a variety of wood thicknesses (using to screws or even some kind of locking mechanism with a small set of bars or even possibly and flat section extending across the gap on the outside with grooves that lock down with small screws.) Thoughts?

what if the cabinet is already assembled can it be adapted to use then

das kann man auch selbst bauen gute Idee

This looks like it fits on one size of wood, is it for 1/2, 3/4, or both? Can it be expanded to hold 24" wide panels? I'm looking at this and the Veritas cabinet system. Anyone have experience with both and can recommend one over the other?

I use mine fairly regularly with a Freud down cut spiral bit. I guess there was not much interest in the product. Seems to be discontinued.

It was too expensive, it didn't allow for multiple thicknesses, and you couldn't put holes in typical base cabinet ends. quality made, of course, not much flexibility.

Iyyy