This article is from Issue 36 of Woodcraft Magazine.
The fast fixers of dull-edges
For all the stories praising the simple card scraper, scant attention is given to the other half of the hook. In order for a scraper to shave, you need a burr, and for that, you need a burnisher. Burnishers didn’t need much attention when scrapers were made from old handsaw blades; the soft steel could be worked with a screwdriver shaft or chisel. Today’s scrapers are made from harder stock. While this metallurgical advancement enables scrapers to hold their hook longer, they can cut through the chrome platings on screwdriver shafts and even scratch the backs of chisels. Store-bought burnishers are tougher and designed with profiles to help you turn an edge more quickly and consistently. Here’s a sampling of what’s available and a few factors to consider when selecting a tool or tools that are right for you.
1. Flat edged/triangular
Similar in feel to the narrow chisel, triangular burnishers, such as the Pfeil (#05B53, $25.99), provide a wide bearing surface to help turn a smooth, even hook. The flat face works well on straight-edged scrapers, but isn’t suited for burnishing curved edges. For that you’ll need a backup round or oval burnisher.
Traditionally reserved for curved-edged scrapers, round rods are sometimes blamed for creating rippled (or “washboard”) burrs. Once you understand that the smaller bearing surface requires less pressure, you'll find that this profile can also turn a serviceable hook on straight edges.
Round scrapers come in two flavors: high-speed steel (HSS) and carbide. HSS burnishers, like the Pfeil (#05S02, $32.99), cost less, but require polishing with a hard felt wheel charged with buffing compound. Carbide costs more, but will not become nicked or grooved.
Another factor worth considering is rod diameter. Blue Spruce’s burnisher ($50, bluesprucetoolworks.com) offers a larger radiused (1⁄4" dia.) carbide rod that’s suitable for two-handed use. Lee Valley’s 1⁄8" -dia. carbide burnisher ($7.20, leevalley.com) can turn a burr with less pressure, and can be used one-handed like paring a knife. The smaller diameter rod is really handy for burnishing convex and concave profile scrapers.
Pfeil’s oval burnisher (#05B52, $25.99) offers the benefits of the flat and round profiles. Use a larger radius portion to draw edges and hook straight edges. The smaller radius can be used on curved scrapers or to direct more pressure on the edge of thinner scrapers without causing the steel to bend away from the burnisher.
Slick and simple self-setters
Woodworkers who rely on honing guides will immediately appreciate the advantages of burnishing jigs. A jig can provide a consistent hook with the least amount of training time and help you turn a burr without clamping the scraper in a vise. Timberline’s SB-1 ($24.95, scraperburnisher.com) is simple but effective. Use the free end to draw the edge, and then run the edge in the slot to turn the hook. Veritas’s variable burnisher (#141636, $38.99) allows you to dial in any hook angle from 0-15°. This jig works well on rectangular scrapers but does not on concave edges or profile scrapers.
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