Heptagonal Marking Gauge

Wheel marking gauges are great layout tools, but their round face means the tool has an annoying tendency to roll, which sometimes results in finding it on the floor with a chipped cutter. By reshaping the outside profile of the tool’s face, it stays put and adds a touch of flair.

This simple improvement takes about 30 minutes. Here’s how to do it:

  1. Buy, download and print the Polygon Marking Gauge Template ($4 CAD) on a sheet of letter-sized paper;
  2. Select between the heptagon, octagon, and nonagon (7-, 8- and 9-sided polygons) and cut it out, staying safely outside the template;
  3. Cut a hole in the centre of the template slightly larger than the wheel of your marking gauge with a sharp brad-point bit or hole punch, using the concentric circles as a guide;
  4. Separate the marking gauge head from the other components, if possible;
  5. Adhere the template to the face of your wheel marking gauge with spray adhesive or double-sided tape using the concentric circles in the middle of the jig and trim any paper extending beyond the face of the gauge;
  6. Shape the face to the desired profile with a metal file or a stationary disc or belt sander. Note that you do not need to remove material up to the lines – having an even distance from each line is enough to ensure an even profile:
    1. If using a file, clamp the gauge head in a vise and file one facet at a time, rotating the head after completing each facet;
    2. If using a stationary sander, hold the gauge face-down on the machine’s table set at 90-degrees to the abrasive. Work slowly, checking your progress frequently and being mindful of the potential heat build-up;
  7. Remove the paper template and soften the resulting sharp edges with a file or fine sandpaper; and
  8. Check that there are no stray filings or other bits of metal inside the marking gauge head before reassembling your wheel marking gauge.

That’s it! I love the look of my polygon marking gauge, and how it doesn’t roll around on my bench (or off my bench!) It’s an easy modification that sees an immediate improvement. I encourage you to give this a try. Feel free to e-mail me with any questions you may have, and send me pictures of your completed gauge heads!