Gunsmithing: Shotguns. Patrick Sweeney

tools come in two types, guided and unguided. The guided tools use the groove next to the one you are filing as the guide, keeping your lines parallel. Unguided tools do not use an adjacent groove, and are used to cut into corners and borders, and to start that first groove.

      One type of unguided checkering tool is the Jointer. You use it on a new job to re-straighten a line that has started to wander because of the grain of the wood, a change in humidity, or the price of e-stocks in Singapore. You also use it to establish your lines across a stock repair that went through a checkered section. Another unguided tool is a bent needle file. The curved file lets you focus your efforts on a short section of your diamonds.