I used a sharpened nail to make the hole, it's tiny. I know its smaller than a #50 drill bit. once I pounded the hole in it, it made a nipple on the bottom, so I flipped it over and used the ball peen side to make the nipple inverted. With the nipple hanging down it was dropping bigger shot, and by inverting it the shot became smaller. There is only one hole because this is the test unit. Now that I have it figured out I may make a different one with multiple holes. With one hole and full of lead it will drop 4 pounds of shot in 15 min. It drops from the hole to theramp thenslides off into the water. If the ramps not hot it can glump up there. I read about using soapstone, but didn't have any lying around so I used some drill bit lube. seemed like cold water would be the obvious choice, but it make more shot explode (looks like coral reef).