Marking gauges have all manner of ways for you to lock the head to the beam, but most involve a screw or wedge mechanism. I think the coolest method I’ve ever seen is a cam-lock on the vintage Star Tools gauge.
The head locks on the beam by twisting the head (or beam). It locks quite well, and without things shifting around like on some cheap gauges. Both the beam and the head look to my eye to have a fairly complex shape to create this interlock.
Boy was I wrong.
This week we’re polishing up a story by Jim Crammond on how to make these gauges for the February 2010 issue of Popular Woodworking. I had to draw the gauge in SketchUp using Crammond’s instructions. It seemed like a wack-nutty CAD exercise, so I blocked out about four hours to complete the drawings for publication.
It took about 15 minutes.
The shapes are simple and elegant. And once you understand how they work, these gauges are a cinch to make. I can’t wait to build a few.
Below is a video that shows how one works. And check out the original patent application and drawings.
– Christopher Schwarz