PWB: As the cutter passes through the layers of cloth, the material has a tendency to want to climb up the outside of the cutter. When it reaches the top, it will wrap itself around the spinning shaft and catastrophe follows immediately. So caution is required when using a spinning cutter against cloth in a drill press. A simpler and less potentially dangerous method is to acquire a bearing race with a 1 1/4" hole, and a ball bearing 1 1/2" in diameter. Years ago, we had several of our shooters who worked for a morto winding factory here, and they broke up old electric motors for these huge balls, but they can also be purchased at a bearing firm in your community...they're a little spendy.
Place the bearing race on a hard surface...I use my anvil, the material over the race and the ball bearing on top of that. Strike the ball with a hammer and the cloth will cut cleanly. Since the ball is a little larger than the hole, the material is pushed down into the race's hole and so the patch will tend to be just slightly larger than the hole in the race. To be even more effective, I grind the race on my belt grinder until the radiused edge becomes a sharp one. Then, less energy is required with the hammer. I cut five in succession, then remove the cut patches to a stack, and continue with the next five. In an hour, you can but hundreds of patches, stovre them in a zip-lock bag with the diameter marked in felt pen...I use this system for everything from .25 cal to .77 cal.
