Hollow & flat grinding
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.
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.
Carl Duguay - [email protected]
Carl is a Victoria-based furniture maker and the web editor at Canadian Woodworking & Home Improvement.
Hi, Carl. Do you have any comments on the various honing guides available? Their ease of use and effectiveness?
Hi Ralph. I’ve used a few different jigs over the past few decades and, in my view, the Veritas MK.II is about as good as it gets. Easy to use, precise, and can accommodate just about any width of chisel/blade. Lee Valley has two new honing jigs that we’ll be reviewing in a future issue of the magazine. I’ve been using the new side clamping guide and it’s great – perfect for the hobbyist woodworker.