About the Banjolin
A banjolin is a small banjo tuned like a mandolin and played with a pick. Look up mandolin lessons, not banjo ones. The designer, a luthier, argues that banjos are ideal for printing: the part that shapes the tone most, the drum head, is a standard part from any music shop. Printing also makes the instrument lighter and water-resistant, which suits a travel instrument.
Metal frets are used because steel strings would wear through plastic ones in a single session. If you don't have fret tools, a local luthier can fit and dress them. There's no truss rod, so print the neck with high infill, or a stiffer filament if it bends. The 3MF files hold the orientation and per-part strength settings. The designer used a 0.8 mm nozzle for most parts and 0.4 mm for detailed ones. PLA has worked for two years, though the ring cracked after long wear and sun, so print it in your strongest material if you can.
The resonator and arm rest are optional. Without the resonator it's quieter and more muffled, because the resonator throws the sound forward. The play-test video shows how it sounds.
What you'll need
Printed parts
- Rim, ring, neck and headstock
- Tailpiece
- Optional: resonator and rest
Bought parts
- Threaded inserts: 8 × M2, 13 × M4, 1 × M6
- Bolts: 8 × M2 × 10, 12 × M4 × 20, 1 × M4 × 40, 1 × M6 × 20
- Banjo fret wire
- 4 strings around .037/.024/.014/.010 (from an electric guitar set)
- Planetary ukulele tuning keys
- A 6 in drum head, lug screws and lug nuts
- Strap pins / end pins
Tools
- A drum key
- Metal files (fret files ideal)
- Soldering iron for inserts
Build overview
- Print and fit inserts. Print in the 3MF orientations without supports, then fit all the threaded inserts.
- Inlay the side dots. Glue strands of contrasting filament into the neck holes and trim them flush.
- Fret the neck. Press in the fret wire, then level and dress it (or have a luthier do it).
- Assemble. Attach the tailpiece and neck to the rim, then the headstock to the neck.
- Fit the head. Press the lug nuts into the rim, fit the drum head with the ring and lugs, and tune it fairly high.
- String and set up. Fit the tuners and strings, then tune.
Print settings
- Supports: None (use the 3MF orientations)
- Nozzle: 0.8 mm for most parts, 0.4 mm for detailed ones
- Neck: Very high infill
- Ring: Strongest material available
Video
Play video: Testing my 3D-printed banjolin (loads YouTube)
Nothing loads from YouTube until you press play. Video thumbnails are © their creators.
Photos
All photos: Schreibmaschine, from the design page on Printables, licensed CC BY-NC. We resized them and converted them to WebP.
7 more photos on Printables ↗