Hollow & Flat Grinding - Canadian Woodworking Magazine

Tool Sharpening: The method you choose to sharpen an edge tool, such as a plane iron or chisel, will result in either a hollow ground or flat tool face. 

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Hollow & Flat Grinding



Illustration by James Provost

If you sharpen a chisel against the edge of a rotating wheel on a bench grinder, the resulting surface will take on a concave shape – referred to as hollow ground. For decades sharpening with grinders was the only option for woodworkers. Over the past decade or so platter style grinding systems, like the Work Sharp or the Veritas Mk.II, have become popular. Because the platter that holds the abrasive is flat, the resulting surface will be flat ground.

Regardless of which method you use, once the blade is sharpened, the edge must be honed on a waterstone or similar flat abrasive surface. This removes any burr on the edge, smoothes the surface and polishes it. On a hollow ground blade you hone only two contact points. Subsequent honings will eventually remove the hollow, so that the blade will need to be hollow ground again. Rather than hone all of the bevel surface of a flat ground blade you create a micro bevel by simply increasing the bevel angle of the blade by about 1º, effectively honing just the tip. The quickest and surest way to hone either a hollow or flat ground blade is with a honing guide. This micro bevel is very easy to maintain. Our experience shows that either method will produce a super sharp blade.