Sandpaper makes a keen edge in a hurry
Synopsis: Stephen Winchester leaves his sharpening tools at home and uses sandpaper to sharpen dull tools when he travels to a job site. He uses a belt sander, a sheet of 120-grit sandpaper, and two pieces of 3M’s Microfinishing film. In this quick article, he explains how to avoid overheating the blade. Photos clearly show how each step progresses.
When I’m in my shop, I sharpen chisels and plane irons with a wet grinding wheel and waterstones. They do a great job, but they’re not very portable. So when I’m on a job site installing cabinets, I leave the wheel and stones at home and use sandpaper to sharpen dull tools.
All I need for sharpening is a belt sander, a sheet of 120-grit sandpaper and two pieces of 3M’s Microfinishing film. It may sound crude, but the edge I get will shave hair off my arm. More important, the edge will shave tight curls off any hardwood I encounter on the job (see the photo above).
“Never use a belt sander on a chisel or a plane iron!” you say. Trust me. A belt sander grinds a bevel quickly, and it won’t hurt the tool as long as you use a light touch. I put a 120-grit belt on my belt sander, set it upside down on a portable bench and take it easy with the grinding. Overheating the blade will destroy the temper, so I don’t bear down on the tool. And I don’t let the tool stay on the belt for more than a few seconds at a time.
Once I’ve eliminated any nicks and established the bevel, I hone my edge tools with the 120-grit paper and the Microfinishing film backed by a piece of scrapwood, as shown in the photos on the facing page. The wood doesn’t have to be perfectly flat—just free of large gouges or cracks.
After honing on the 120-grit sandpaper, I use 60-micron and 30-micron Microfinishing film. The grades get finer as the number goes lower. The 60 micron is equivalent to about 220-grit, and 30 micron is about the same as 400-grit paper.
This stuff lasts forever, too. I’ve been using the same pieces of film for two years.
From Fine Woodworking #117
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