As a knifemaker, peening pins is something you're going to do -- a lot. Traditionally, pins are used to hold most parts of a knife together on both fixed blade knives and folders. Of course there are alternatives, such as screws and Corby or Loveless bolts, but they are more expensive than pins. Some knifemakers use epoxy to simply glue pins in place but epoxy will eventually degrade and fail. Correctly peened pins will last a lifetime. So what does peening pins mean? Essentially, it means applying force to the pin in order to create a mechanical bond between the scale and the knife handle. Or more simply, hammering each end of the pin compresses it, causing it to swell and bind in the hole, locking the pieces together. For this tutorial, I'll attach scale material to a knife handle. This is a typical situation, and one of the easier jobs involving pins. The pins are 3/32" and the scales are micarta. The micarta is already attached to the handle with epoxy and the holes are drilled for the pins, so let's get started with the pins. Note: Although I didn't show this part in this tutorial, when peening your own pins, make sure the holes are straight and just big enough to fit the pins. If the holes are too big, the pins won't hold and may bend. The first step is to prepare the pins. You'll need to cut them and file them for peening. Use a Dremel with a cut-off wheel or a hacksaw for larger pins like these. For small 1/16 or less pins, you can also use wire cutters. Cut them a bit long so you can file the ends flat. The flat surface lets you peen the pins evenly. The pins should be just long enough so that about 1/16" 1.5mm) sticks out on both sides of the knife handle. Too short and you won't be able to peen the ends enough so they hold anything together. Too long and you'll end up with a huge mass on either end that won't seat in the material properly. Now it's time to take up the hammer. Lay the piece flat on your anvil or the anvil part of your bench vice. Don't worry that the knife handle slides down to the bottom of the pin. Using the round or ball end of your ball-peen hammer, start tapping around the edge of the pin. You want to strike the edge of the pin, not the centre. Peening pins calls for finesse not brute strength. Use a small hammer and gently tap around the edge. You'll see the pin start to develop a dome that is wider than the pin below. Smaller diameter pins, or those made of softer metals will move much faster. Once the dome starts, turn the piece over and start peening the other end of the pin. Continue the process, flipping the piece every few taps, until the domed ends are tight against the piece. The scales should be well fastened to the knife handle now. (To finish off, I like to give each end a few good taps right in the middle of the dome to help compress and expand the pin.) Using your files or sand paper or grinder, finish off the piece by grinding away the dome until it's flush with the scale material. Optionally, you may choose to leave the dome ends and simply sand them smooth and shiny. That's the basics of peening pins. Later tutorials will cover attaching metal to metal and peening pivot pins.