This is how I built a custom holster for my s&w 686 revolver. The scraps were procured at hobby lobby for 8$. It's not tooling leather but does the trick. Be safe when handling fire arms, I claim no responsibility for your stupidity!
Step 1: Tools And Materials
Tools: 4 hole punch, multi- hole punch, hammer, carving knife, edger, leather/wood burner, rivet and snap setter, crush rivet gun, needles, torch, belt sander.
Materials: scrap leather, nylon thread, leather cement, crush rivet, rivets, snaps.