A case for marking gauges
When it comes to marking cutlines and laying out joints, it’s hard to beat the simplicity and accuracy of a marking gauge. To uncover the fundamentals of marking gauge setup and use, we consulted renowned master craftsman Frank Klausz. Here’s how Frank gets the most from his favorite layout tool.
A marking gauge provides a fast and accurate way to mark lines parallel to the edge of a workpiece, either with the grain or across it. A marking gauge's advantage over a pencil is that its pin, which Frank sharpens to a knife edge, produces a very fine mark that does not broaden, and it scores the workpiece for chiseling and saw cuts (preventing splintering). Here are a number of ways you can use one:
- Mark the center of boards for resawing.
- Mark stock edges for joining.
- Lay out lines for cutting joints, such as dovetail or mortise and tenon.
The basic marking gauge consists of four parts: an 8– to 12"–long beam, a fence, a fence-locking device, and a marking pin, as shown on Drawing 1. The fence slides along the beam to set the required marking distance to the pin. A locking device, such as a thumbscrew or wedge, secures the fence to the beam at the set position. Some gauges have a removable marking pin, which makes it easy to sharpen the pin or replace it. Also, the beams of some gauges are ruled to allow for direct setting of the marking dimension without the need for measuring.
One type of marking gauge, a mortising gauge (photo at the top of the page), has a single marking pin for general layout and another pair of pins on the opposite side of the beam for easy mortise layout. One pin is fixed and the other slides in the beam to set the mortise width.
For a marking gauge to work correctly, Frank notes, you need to focus your attention on its smallest part—the marking pin—and make sure it has the correct shape, projection, and angle.
- Shape: Most new marking pins have a conical point, which will tear wood fibers rather than slice through them. To prevent this, sharpen the pin to a knife edge, as shown on Drawing 1a.
- Projection: For best control, adjust the pin so it projects 1/16" from the beam.
- Angle: Because a gauge works best when you pull it toward you, angle the point approximately 5° away from the fence, as shown on Drawing 1b. The angled pin will draw the fence against the edge of the stock when marking.
Because the fence follows the stock's edges, make sure they are straight and smooth for accurate marking.
After securing the fence, recheck the setting to be sure it hasn't changed. Practice marking on scrap first to verify the setting.
Position the fence against the stock's edge, and apply light pressure to keep it flush. Rotate the beam so the pin is at an angle to the stock (as in the photo at the top of the page), and then lightly drag the gauge to make your mark.