Walter Sorrells demonstrates how to make a knife filing guide in this video. A knife filing guide is a handy jig that helps smooth the transition between the tang and the ricasso on hidden tang knives. It helps you file extremely square, even shoulders on knives. If these corners are not filed symmetrically and dead flat, there will be ugly gaps between the blade and the guard. This file is useful for making a host of knives, from Bowies to kitchen knives.
Walter says he’ll be using some fancy equipment, but there’s no reason anyone can’t use basic tools. The idea is fairly simple and you can get the gist of it, which will let you make this with a simple drill press.
He begins with a piece of 01 steel. For those just getting started on knife making, 01 is one of the best steels to work with, because its versatility can be used for any number of tasks. 01 is sold in precision ground form, and can be found from many suppliers.
The filing guide is composed of two small plates that clamp together in a specific way. First, he cuts the pieces out. He’ll be making his guide about three inches wide, but you can choose to make that bigger or smaller. The stock he has on hand is a little oversized, so Walter thins it down with a mill.
He then drills some quarter-inch holes in the top to accommodate the shank of the quarter-twenty stainless steel cap head bolts. Then he drills corresponding holes with a number 7 numerical size drill in the second plate. Those holes will be tapped for the twenty-quarter thread. He uses very precise measuring instruments to accomplish these. The key thing is to have the holes lined up precisely.
He taps the threads, which has to be done carefully. He breaks one tap in the hole, and has to drill it out. He cleans up the plates on the grinder, heat treats and tempers them to make them hard enough to withstand the file and tests that the screws fit. Lastly, he demonstrates how the filing guide is used to make a sushi knife.