Woodworker's Journal 1993-17-3, страница 20

Woodworking Basics

Continued

Scraper Paraphernalia

Woodworkers love gadgets. and even a simple tool like the scraper has attracted a few 1 find that the hack of a bevel-edged chisel works just fine as a burnisher. If you're concerned about slicing yourself with the chisel, you might try a rod burnisher, like the Veritas one shown. I didn't carc for the Ulmia wheel burnisher, which can lie used only for turning the burr. Because of it's size and weight. I found it hard to use with a light touch. But a friend who uses

a sharpening technique that produces a heavier burr had g«xHi luck with it.

The Veritas variable burnisher allows you to select and reproduce time after time any burr angle between 0 and 15 degrees. Hie 0 degree setting is ideal for burnishing the scraper edge without rounding the arrises. The tool is smaller and lighter than the Ulmia. and I had good luck with it.

If you're uncomfortable burnishing and turning the burr on your scraper with the back of a chisel, here are three alternatives. The rod burnisher and adjustable burnisher on the left are made by Veritas; Ihe wheel burnisher on the right is made by Ulmia. All three items are available from Garrett Wade, tel. 1-800-221-2942.

longer get results from burnishing, return to the stones (perhaps even the file) and rework the faces and edges.

Using Ihe Scraper

It's not difficult to make a sharp scraper work well. Grasp the tool with both hands, thumbs in (he middle tow ard the bottom edge. Rex the steel slightly with your thumbs as you put it on ihe wood, lipped forward at an angle of 70 or 80 degrees (Photo F). Push the tool away from you. adjusting the angle slightly if the edge doesn't bile immediately. (I haven't had much luck pulling the scraper, but some people highly recommend it. so you might give il a try.)

Always scrape parallel to the direction of the wood's grain. As with a sharp hand plane, you shouldn't have to push very hard to raise good shavings. If the edge doesn't bite well or if you're applying a lot of pressure and producing more dust than shavings, try burnishing the faces and turning the burr again: if

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Photo F: Flex the scraper slightly with your thumbs as you push it along the wood. A sharp tool should "bite" the wood and you shouldn't need to push very hard to create shavings. The scraper is skewed to the grain, but moved in the same direction, not across grain.

that doesn't work, move back to the stones.

Cover the surface you're working on in much the same way you would with sandpaper. Overlap sirokes: work methodically. Unlike a plane, a scraper has no sole to ride over low spots, so it tends to follow and emphasize any surface contours, which can become quite noticeable under a glossy finish. To

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counter this tendency, every few passes alter the angle ai w hich you hold the toot across the grain—skew the tool 30 degrees to the right, then 30 degrees to the left for example. (Regardless of ihe angle of the tool to the grain, always scrape with the grain, just as for sanding.) If you're removing a blemish, be sure to feather the spot gently into (he surrounding area.

Now lhal I've seen what a sharp scraper can do. 1 think it can replace much of the sanding I do on hardwoods. (My attempts to scrape softwoods have met with mixed results, depending on the wood.) Even ihe sharpest hand plane tears some wood fibers, particularly those that rise at a steep angle against the direction of the plane's travel. (It is this "short grain" that produces the lovely highlights in crotch veneers, for example.) The scraper removes these tears much faster than working through several grits of sandpaper. But the scraper doesn't produce the glowing, silky

smooth surface possible with 220 gril or finer paper. So for certain projects, the sanding block and dust mask appear unavoidable.

Keep Trying

From what I've discovered about the scraper, I suspect that a roomful of woodworkers would produce a roomful of different scraper-sharpening techniques, The one I've just outlined works for mc. and I trust il w ill work for you. Bui have patience—simple as this tool is. chances are it will take you some time to get il to work right. And don'i be afraid lo experiment iry a variety of sharpening techniques. Burnish ihe edge as well as the faces: don't burnish at all: try turning the burr right after filing: vary the pressure and angle when forming the burr: polish the faces and edge and see if the tool cuts well without turning a burr. I've read accounts advocating each of these methods. See w hat you make of them.

The Woodworker's Journal