Popular Woodworking 2000-06 № 115, страница 10
Illustrations by Mary Jane Favorite sanding, they have an "open coat" — 40 percent less abrasive on the surface. They cut a little slower, but they last much longer. The open coat prevents the metal filings (the swarf) from becoming impacted between the grits and "loading" the paper. I also look for stearate-impregnat-ed paper; this too reduces loading. For most sharpening tasks, I work my way through four grits — 120#, 300#, 600# and 1,500#. I keep these all on one side of the pastry stone. On the other side, I have #50, 100#, 220# and 2,400#. The two coarse grits are to recondition badly damaged edges. The 220# provides an intermediate step between 120# and 300# when I'm flattening the backs of large chisels and plane irons. And the super-fine 2,400# is the last step when I'm flattening something. As you sharpen, brush away the swarf frequently. I use the stiff bristles on the back of a file card. This keeps the abrasive clean and helps prevent loading. The last step in my sharpening process is stropping. This is the secret ingredient in every successful sharpening formula, no matter what abrasive material you use. Stropping removes tiny burrs and refines the cutting edge, making it as keen as it can possibly get. For this step, I've mounted a piece of leather to a hard maple board and "charged" it with chromium oxide, a polishing compound. (You might also use jeweler's rouge or tripoli.) Why not mount the leather to the pastry stone? Leather is considerably thicker than the sandpaper. Because of the type of honing guide I use to maintain the sharpening angle, it's important that the stropping surface be at the same level as the other abrasives. I've planed the wood to adjust for the thickness of the leather. The Secret Weapon — The Very Scary Honing Guide Yes, I use a honing guide. I know that some experienced sharpeners look down on these jigs as "training wheels," but I don't. If the first secret to successful sharpening is to hone with progressively finer grits, the second secret is to maintain a precise cutting angle as you do so. And you can be much more precise with a guide. After all, if our hands were all that good at maintaining an angle, we wouldn't need planes to hold plane irons. One of the reasons some folks don't like honing guides is that the current commercial crop is difficult to adjust and not especially versatile. The homemade jig that I've developed holds a chisel by its handle rather than the blade. Because the jig makes a large triangle with the abrasive In addition to chisels, the guide will accommodate gouges, plane irons, skews and parting tools. surface and the tool, it's easier to adjust and maintain the sharpening angle. The tool holder conforms to every chisel handle that I've been able to find, and it's wide enough to accommodate an iron from a jointer plane. Additionally, the holder pivots, and it can be locked in place or adjusted to roll around an axis. This makes it possible to sharpen not only chis- Continued on page 16 |
