The Best Way to Sharpen Tool Blades

Enlarge Image Image Gallery See "The Best Way to Sharpen Tool Blades" for tips on sharpening chisels. STEVE MAXWELL

February/March 2007  Issue #220

By Steve Maxwell

The best way to sharpen wood chisels (and plane irons and knives as well) doesn’t necessarily involve sharpening stones. Even though I own a dozen fancy stones, I don’t use them anymore. Instead, I turn to my shop-built buffing wheel, because it works so quickly and so well. It’s also very simple.

Picture a hard felt disk about 8 inches in diameter and 1 inch wide, its edge saturated with a fine, waxy abrasive compound, mounted on a spindle spun by a motor. That’s all there is to a buffing wheel. You press the edge of a dull tool against the edge of the spinning wheel, and in a minute or so it’s sharp enough to shave hair cleanly.

You’ll need to address a couple of preliminary details to assure consistent success. Before using the buffing wheel, grind the tool edge to the proper angle. For conventional woodworking chisels and plane irons, this means a tip angle of 25 to 30 degrees. Most new tools come ground to an acceptable angle, though eventually you will have to re-establish this angle. Tool angles get blunt after repeated use and honing. And don’t procrastinate; once you get past a bevel angle of about 40 degrees, you won’t be able to hone a sharp edge, regardless of the sharpening system you use.

A bench grinder with a cool-running abrasive wheel is a good choice for correctly shaping woodworking tools before final honing. Cool-running wheels are made of aluminum oxide with a relatively soft bond and cause much less heat buildup on the tool than regular grinding wheels. This is significant — if a chisel or plane iron gets too hot to touch, the properties of the steel will change so that it can’t hold an edge for very long. Even with a cool-running wheel, dip the tool tip in water after every three or four seconds of grinding time, just to be safe.