One String, One Print, One Harp

To exclude musical instruments in the overflowing library of possibility that 3D printing enables would be a disservice to makers and musicians everywhere. For the minds over at [Makefast Workshop], an experimental idea took shape: a single stringed harp.

The TuneFast Harp needed enough notes for a full octave, robust enough to handle the tension of the string, a single tuning mechanism and small enough to print. But how to produce multiple notes on a harp out of only one string? V-grooved bearings to the rescue! The string zig-zags around the bearings acting as endpoints that rotate as its tuned, while the rigid PLA printing filament resists deforming under tension.

After a bit of math and numerous iterations — ranging from complete reconfigurations of part placements to versions using sliding pick mechanisms using magnets! — a melodic result!

Assembling the harp, the main points to note are ensuring the bearings rotate freely — otherwise, your tuning will be off — and giving each note’s section of string a quick check to ensure even tension. The TuneFast harp works with most standard guitar strings — though steel strings may cause the harp to deform further — and once tightened to a reasonable degree, it’s ready to play! Further fiddling will change the key, but that’s up to the maker-musician’s discretion. Paired with The Hovalin and a few others, you have the makings of the first 3D-printed orchestra.

Filed under: 3d Printer hacks, Musical Hacks