Marking Gauge for curves

Greetings fellow craftspeople,
I recently built a leaf box which required scribing a line 3/8” away from a curved edge. The fancy marking gauge that I built last year works great for straight edges, but is useless for tight curves. For my project I made a quick temporary guide by inserting a dowel into a piece of wood and drilling a hole to hold a pencil with a friction fit the correct distance to produce a 3/8” offset. It worked well but was not adjustable, so basically a one time use. Photo is enclosed.

After warming up my brain with enough Pinot Noir, I eventually came up with this design. It’s based on the same principle as my temporary one, where a round dowel rides against the curved edge with the pencil held a given distance away. I ripped a piece of walnut in half, added a piece of maple to one half, and routed a groove down the center of both pieces. Once glued back together, this creates the opening for the center shaft which holds the pencil. I added a thin piece of Wenge to cover the back, because a shop project just isn’t complete without some Wenge.  Brass threaded inserts were added to hold the knobs. Lastly, a small brass ruler was inset, making small incremental adjustments in the routed slot until it was dead on accurate. 

I was initially planning on this gauge being smaller, but the width and height were determined by several factors, starting with the center shaft. Its width of 7/8” is determined by the width of the pencil, plus enough extra to allow for the brass insert (1/4” both sides). It needs to be tall enough so that the knob tightens against a flat portion of the pencil, not the sharpened part, so I made it 1 1/8” tall. The outer piece also needs enough room for the second brass insert, so I added 1/4” all around to produce the 1 3/8” x 1 5/8” final dimensions. As it turns out, once the edges are rounded over, it’s very comfortable in your hand. It’s now my go-to marking gauge.