Use: with the pickgun needles, you can create a diamond pick for restricted keyways. Or, you can use it as a single pin picking tool for tubular cylinder keyways, (which, by the way, I've never been able to pick, nor have I tried that hard).
Materials:
Drill and drill bit. (Nit should be about the size of the diameter of the tightening cylinder of the exact-o-knife)
Dremel with cut-off wheel (if not availible, use a file)
exact-o-knife handle.
Sharpie, thin-line.
Ruler. 6-inch (try one with a metal edge)
Pick-gun needle picks.
Procedure: Drill the tightening cylinder a little bit larger than it should be, not too much, just slightly larger on the inside.
Using your ruller and sharpie, design your diamond to the shape and size that you'll prefer to have on the needle pick.
Using your dremel, cut out your design.
File the u-shaped end until it fits the exact-o-knife's tightening clamp cylinder.
Viola! to quote JuJitsu500 (its voila) you have a diamond and handle perfect for restricted keyway access.