Thursday, March 26, 2009

tuning your scraper

I wrote recently about a cabinet scraper. Its a tool that is so useful on a daily basis and yet many a contemporary cabinet maker doesn't know how to use one, let along how to sharpen one. I hope that the following is not too much information for those who are never going to make furniture. It is my hope to give you a sense of what you must do to keep your tools "tuned" in the shop. Sharpening tools is a necessary part of the making of cabinets and furniture. It is also of course a viable metaphor for what we all have to do in our lives. It takes "away" from the making of the "thing" but without keeping our tools sharp and ourselves, we would struggle and fail to accomplish our goals. So here is a basic primer on sharpening a cabinet scraper.

The sharpening is accomplished on a maintenance basis using a hardened piece of steel attached to a handle. Think of a screwdriver without the "business end" still intact and that's the idea. They make burnishing tools that are for this purpose too, but the French craftsman I trained with had just a modified screw driver handle and shank. You have to be able to hold the tool while exerting some force on the edge of the scraper and also the steel has to be at least as hard as the steel in the scraper. There are two essential motions that one performs. This is assuming by the way, that the scraper has already received an initial dressing with a file followed by a sharpening stone. The first movement is to go across the scraper like one would do with a barbers blade on a stropping strap. Back and forth across the flat scraper in the same plane as the flat orientation. It helps to be doing this on the surface table of a machine. The goal is to create a little burr that "grows" outward ever so slightly but in line with the scraper. This motion can be repeated many times, as the more the metal is moved here the better the final result will be (within reason). The second motion is a one shot deal that occurs for all four edges that will cut. Two per long edge, one on each side. The burnisher is held at almost a right 90 degree angle to the scraper , but tilted ever so slightly toward the flat, at about a 80-85 degree angle. The scraper has to be held flat on a preferably metal bench part of a machine such as a jointer, with about 1/4" of the tool protruding away from the edge of the machine. You must have a very firm grip on the scraper pressing down and on the burnishing tool pressing against the scraper. You get one shot at this and there is no going back unless you want to start over. Hold the burnisher low so that you don't cut your hand against the edge of the tool! Start as close to the far corner as possible and pull towards yourself while pressing against the edge at a constant 83 degree angle (approx!) and that is it. Repeat 3 more times on each other edge. You will get a burr now pointing up that you can feel with your finger. When you slightly bend the scraper with your thumbs in the center while holding the outside edges and press along a piece of wood you should get very thin shavings of wood. If you are producing dust, it is not sharpened properly or you are not holding the scraper properly. If you are trying to follow along and do an actual sharpening, good luck and I hope I gave you enough information! I'll be happy to answer questions and welcome your feedback.


  1. This was a fascinating look at what goes into the art and craft of woodworking. Obviously the tool, its angles, the way you hold it in your hand have to become an extension of both your body and your psyche when making furniture. Very cool.