The Bridge Stack
The D-18 Listening Project · Structure viewer

The Bridge Stack

Bridge, top, bridge plate and X-brace legs for two D-18s, drawn to one scale in inches on one origin: the centerline at the pin-hole line. Rotate them together, lay one over the other, or cut them open.

Prototype. Shapes are placeholders; the differences tagged “From notes” come from the 1938 vs. 1948 comparison.
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What’s real here

The differences in the spec sheet tagged Notes come from your 1938 vs. 1948 comparison and drive the models: six-sided vs. four-sided plate, 0.090″ vs. 0.105″ plate, tucked vs. untucked, contour at vs. ¼″ behind the pins, 2 5/16″ vs. 2 1/8″ spacing, ebony vs. Brazilian, X crossing ~1″ vs. ~1 7/8″ off the soundhole, scalloped vs. tapered. The 1948 top thickness is the 52-position mean.

What’s placeholder

Everything tagged Ph. is a stand-in: bridge outline and heights, plate outlines, brace heights, saddle size, the 1938 top thickness. Where there is no data, both guitars use the same stand-in, so the only differences you see are the documented ones.

Swapping in measurements

  • Every number lives in one GUITARS block at the top of the script, with its source tag.
  • Plate outlines are lists of corner points in inches from the pin line (x toward the tail, y toward the bass).
  • Adding a third guitar is a new entry in that block. It appears in both menus.