I recently purchased a couple of mortising chisels for those occasions where only a couple of mortises are required. I’m currently flattening the backs of the chisels. Given that mortising chisels are often subjected to a fair amount of abuse, is it advisable to hollow grind the face of the chisels before sharpening, or should they be left flat as they came from the factory? – Jack Dobrian
Tim Inman: Sharp is really the ultimate criterion. Hollow grinding is easiest, and usually just fine. The micro-bevel at the leading edge is what really forms the cutting edge. Keep it small and sharp! Cutting mortises is not a fine art. It is the “dogwork” of the joiner. It is important work, and the cut and fit are important. But my advice is: Don’t overthink this. Sharpen the chisels, get some scrap and practice until cutting those mortises is second nature. Resharpen often. Be sure to mark out the perimeter of the mortise with cuts before you go in to chisel out the remains. You might give him a look. Hurray! for you learning to cut mortises the “old'”way! You’ll quickly find it is a fast and efficient way to make a great joint. I prefer using hand tools anywhere I can.
Chris Marshall: I would also be careful to keep the sides of the mortising chisel blades square to the back — they help to scrape the long sidewalls of the mortise clean as well as square the ends of the opening as you leverage out the waste. Good luck learning to cut mortises by hand; I don’t do it as often as with other machine-tool methods, but it is fun to do when the need arises. I’ve even used a mortising chisel as a final cleanup tool when hogging out mortises with a drill press. Works great for that application, too.