American Woodworker

Important Information >>


Q & A: Cutting Gauge Tune-Up



Cutting Gauge Tune-Up


I bought a new marking gauge to cut across the grain when I lay out tenon shoulders and dovetails. The problem is, it doesn’t make a clean cut. All I get is a raggedy line.How can I sharpen the tiny cutting knife to make it work better?


Marking gauges come in two different styles. One with a needle- like pin works best when following the grain of a board. This is the kind to use when laying out the two sides of a mortise, for example.

The style you bought has a knife in it instead of a pin, and is sometimes called a cutting gauge. It’s meant to be used across the grain, as you describe. It should make a cut as clean as one made by a razor blade. Here’s how to fix yours:

You’ll have to change the profile of the knife from pointed to round. A cutting edge that is a single point dulls quickly. A round edge will stay sharp longer because there’s more cutting surface. Also, change the double bevel to a single bevel. A single bevel facing the gauge head pulls the head tight to the edge of the wood.

Remove the knife from the stock of the gauge. If the wedge that holds the knife is tight, pound it out from the bottom with a hammer and punch. Then flatten one side of the knife on a piece of 220-grit sandpaper. Next, make a holder from a length of 3/8-in.-dia. dowel rod. Saw a 1-in.-long kerf in the end of the dowel to hold the knife. A bandsaw cuts a kerf about the right thickness. Insert the knife into the kerf and bind with tape.

Bevel the knife with a grinder or belt sander. Use a fine wheel or belt. A round profile is created by rotating the dowel on the tool rest. Grind past the old double bevel until the new bevel intersects with the side you flattened, and is round from side to side.

The angle of the bevel should be about 30 degrees. Use a light touch when grinding this thin piece of steel, so you don’t overheat it and draw the temper out. Take it out of the holder and remove its wire edge on the sandpaper.

This story originally appeared in American Woodworker June 1999, issue #73.

June 1999, issue #73

Purchase this back issue.