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Personal project

3D-Printed Guitar Capo

Problem: Make a 3D-printed capo for an acoustic guitar that works at more than one fret.
Date: Jan 2026
My role: Personal project: design, printing and testing
Tools: SolidWorks, 3D printing
Result: Fourth version has a working print-in-place hinge and ratchet. It works, but only roughly.

SolidWorks render of the one-piece capo: U-shaped clamp with a lever arm on a hinge — Full CAD assembly

Section view of the capo assembly cut through the print-in-place hinge — Print-in-place hinge, section view

Second section view of the capo's print-in-place hinge — Print-in-place hinge, second section view

All capo prototypes lined up in order on a wooden table — All design iterations

First capo prototype, a flat bar held with rubber bands, mounted on a guitar neck — Initial design

Third capo prototype held in hand, with the hinge fused shut — Third design with fused hinge

Final capo prototype held in hand with a working hinge — Final design with functional hinge

Approach

Measured the fretboard at several points, since the neck gets thicker further up.
Commercial capos use metal torsion springs. A plastic print needed a different way to apply pressure.
I did no calculations. It was trial and error: I changed dimensions between prints until it roughly worked.

Iterations

1: two pieces with rubber bands and a flat bar. Hard to attach, and the bar bent, so the middle strings did not sound right.
2: one-piece clip with a rubber band. Easier to attach, but the bar still bent.
3: lever arm on a print-in-place hinge with a ratchet. The hinge fused, and it only fit the first fret.
4: the hinge and ratchet work, and it is easy to attach.
The design went through 7 CAD versions in SolidWorks (v1–v6 and v8).

What I learned

Designing print-in-place hinges and a ratchet in SolidWorks
The importance of accounting for deflection in designs