The tools on the right, are the main specialty tools needed for holster making--the over-stitch wheel to mark stitch spacing, the adjustable groover to cut a groove a fixed distance from the edge, and the beveler to round the leather edges. Each hole has to be drilled or punched prior to sewing--I used a drill press with a bit made from a stainless steel bicycle spoke. Sewing is by hand with two needles--each needle goes through each hole. Once sewn the holster is wetted, the gun is inserted, and the leather is pushed in to follow the details of the gun. When the leather dries, it should be quite stiff, and should hold the gun securely upside down.
Update: While I am happy with the construction of this holster, the design leaves quite a bit to be desired. I was attempting to do a holster that sits very low--the thin size of the P3AT makes getting a good grip difficult. The holster does not sit well, with quite a bit of butt sticking out under normal circumstances. I believe that this is because the belt loop under the grip is too long and flimsy, and needs to be closer to the gun.
I have built a pancake holster for my J frame and took pictures, I
plan to publish posted the beginning of a fairly detailed and illustrated howto in the next few days. here