Master the Mortiser
Simple tips for sharpening, setup, and cutting sequence
Synopsis: They can cut mortises of almost any length quickly and accurately, but hollow-chisel mortisers are among the most finicky of power tools. When not properly set up and used, this is a machine that can plague you with jammed chips, overheated bit and chisel tips, burnt workpieces, and broken parts. But once you learn the right way to set up your mortiser, you’ll find this aspect of joinery turns effortless. Fine Woodworking contributing editor Roland Johnson shares his tips, starting with the proper way to sharpen and install the chisel and bit, and ending with advice on cutting expert mortises.
A mortiser, also called a hollow-chisel mortiser or mortising machine, cuts mortises remarkably quickly and accurately. Indeed, this machine can cut a typical leg-to-apron mortise in well under a minute. Benchtop models are most common, although larger, freestanding machines also are available.
On the downside, mortisers define the word finicky. If yours isn’t set up and used correctly, you’ll wonder why you bought one.
Fortunately, mortiser-induced headaches can be treated with relative ease. Simply follow the steps outlined here, and you’ll find that quick, clean, and accurate mortises become the norm, not the exception.
A sharp chisel and bit are a must
A mortiser won’t work effectively when the bit and chisel are dull, so keep both parts sharpened. No need for a lot of tools, just a chainsaw file, a round and a flat slip stone, a little sandpaper, an abrasive pad, and some honing oil. Don’t expect a brand-new bit and chisel to be adequately sharp. Almost all I’ve seen needed extra attention out of the box.
Hone the outside faces of the chisel—I begin sharpening by honing the four outside faces of the chisel. To ensure an adequately flat…