The Qwistle

The Qwistle was designed during May and June 2014. Initially based on an earlier "Paper Whistle" design (also on this site), it was created specifically for printing on FFF (Fused Filament Fabrication) printers derived from the RepRap project, which were becoming widely available as affordable, often home-built desktop 3D printers.

The immediate impetus was the success of the Dreaming Pipes Kickstarter in March–April 2014. A "penny whistle" STL kit was one of the rewards offered and was first imagined as an FFF-friendly version of the existing Paper Whistle. It quickly became clear that the project was a chance to develop something more ambitious: a whistle that would go out to, and be test-printed by, most backers, providing rich feedback on 3D-printed musical instruments. The simplicity of the penny whistle, combined with the musical demands of traditional repertoire, made it an excellent testbed, and a substantial amount of time and effort was invested early on in designing and prototyping what was intended to be a professional-grade instrument.

Modular STL set and printer constraints

As with all the Dreaming Pipes STL kits, the Qwistle was made modular. This allowed part sizes to be restricted for use on even the smallest and cheapest printers. The Printrbot Simple, which at that time was available fully assembled in the UK for around £300–£400 with a Z height of about 100 mm, was used as the benchmark.

The Orion and Ultimaker 2 printers used in development have more than double that Z capacity, but accessibility was a key requirement for all Dreaming Pipes kits, and both were substantially more expensive machines. Parts were split where needed, not only to respect the 100 mm limit but also to improve tone in the finished instrument. The fipple in particular was divided so all components could be printed without support, avoiding the surface damage from supports that can spoil tone or even de-voice the whistle. A tuning slide was included to give fine pitch control.

File set design, printing and finishing

One of the biggest challenges in producing an instrument as a 3D-print file set is ensuring that it will yield a good instrument on as wide a range of printers as possible. The Dreaming Pipes projects provided an ideal opportunity to experiment with this, and various approaches have been tested.

In the Qwistle's case, the file set was designed to work "off the printer" with minimal finishing. All joints are thread-sealed in the manner of bagpipes, using PTFE tape (readily available from plumbers' merchants) to provide an airtight, renewable seal. The main exception is the fipple–mouthpiece joint, which must be glued with a suitable gap-filling adhesive.

Two aspects of the whistle are especially vulnerable to variations in print quality:

• Scale temperament, which suffers if finger holes print slightly off-round.

• Tone and voicing, which are affected by any roughness or "flash" in the mouthpiece and fipple area.

Both issues are easily addressed using well-established whistle-tweaking techniques.

Hand finishing and customisation

Because the Qwistle relies on hand finishing, the outcome is pleasantly open-ended. Although the original aim was to provide a whistle with sweet, focused tone, moderate volume (stronger than the Paper Whistle), a clear but sweet bottom hand, easy octave crossing, sweet high notes and a well-tempered scale, in practice a player with the STL set, a 3D printer, fine sandpaper and some basic whistle-tweaking know-how can shape the instrument toward a wide range of voices.

For those with CAD skills, the Qwistle's modular design also allows direct adaptation of any part – mouthpiece, windway, body sections – to explore further variations.

This potential for customisation has already been used to good effect. Dreaming Pipes backer Bill Owens created an entirely new instrument, a Qwistle-derived tabor pipe. Custom Qwistles have been produced in several pitches, keys and bore sizes; examples include wide-bore B♭ and A Qwistles with a flute-like tone, and a whistle customised specifically to provide a scale suitable for Alasdair Roberts' song Hurricane Brown, performed at the Glad Cafe, Glasgow in 2015.