Design Concept

While watching a Led Zeppelin ‘Rock’umentry there was some footage of Jimmy Paige playing guitar with an ammunition belt style guitar strap. Instantly there was a design in my head of a 3D printed version of the guitar strap. So, while it is possibly a crazy idea to build a guitar strap from hard plastic, I had to build it. It turned out to be pretty good, strong, flexible, and comfortable enough considering its build from hard plastic. I think it looks great, certainly unusual.

Design details

It is made by printing sections of interlocking repeating Core Pieces, which are printed in-place containing as many pieces as the print bed width will allow. Each section of interlocking core pieces ends with a Core Joining Piece and Insert, which are used to attach two sections of core pieces together. Therefore, multiple sections can be printed then joined together to create a strap of the length needed with any size of printer. At each end of the completed PLA strap is a special Start Adaptor Piece and End Adaptor Piece to allow the PLA strap to be joined with the TPU Soft Guitar Attachment Piece. The Soft Attachment Pieces allows the PLA strap to be attached to the guitar like any usual guitar strap and the soft TPU prevents the guitar from being scratched by the PLA sections.

How many parts to print?

The following parts are essential to build a strap and add the following length to the strap:

• 1 x Start Adaptor Piece = 21mm

• 1 x End Adaptor Piece = 18mm

• 2 x Soft Attachment Part = 70mm each (140mm per strap)

Totaling 179.5mm required length per strap. Removing this from the desired strap length gives the length needed to be built in Core & Core Joining Pieces. Each one of these pieces adds the following length to the strap:

• Core & Core Joining Pieces = 21.5mm

Therefore, the Number of Core Pieces N = (Required Strap Length – 179.5) ÷ 21.5

I wanted my strap to be 1300mm, therefore, I needed to print 52 Core Pieces according to the following:

N = (1300 – 179.5) ÷ 21.5

N = 52.1

With the above you can determine how many Core pieces you need to make a strap of the length you require. I suggest measuring a strap you already own; you need the length between the points the strap attaches to the guitar (in mm). The number of Sections (of Core Pieces) and Core Joining Pieces will depend on your required strap length and your printer bed size.

Detailed assembly instructions are included in the downloads section of this model. The print settings (.3mf file) is provided for a K1C printer and show how multiple sections or interlocking core pieces are printed, the uploaded file will print my 1300mm strap pictured. So you will likely want to adapt the file for your needs.

Design Quirks

• Once built the strap length is not easy to adjust; but once you have a normal guitar strap at a length you like how often do you change it? Not often. It is adjustable though, by adding Core Joining Pieces or sections of core pieces for big changes.

• It is not as comfortable as a soft strap, but not bad (considering it’s built with hard plastic).

• It’s strangely noisy to put on, like a rattle, but not noisy while playing as the guitar’s weight keeps the straps sections taught which prevents the noise. It’s just noisy when you put it on. I quite like the noise though. You will have to print it to find out what it sounds like!

• The TPU Soft Attachment Pieces are hard to pull through the PLA end and start pieces, which is reassuring I guess, you know it won’t come apart.

Print Settings

2 Plates of PLA for the Core Pieces. One Plate of TPU for the Soft Attachment Pieces

* Auto Tree Support enabled but only needed for the Core Joining Pieces.

* Auto Brim enabled again for the Core Joining Piece Inserts

* Make overhangs printable - tom make sure the slots in the pieces don't need support

Guitar Strap (Ammunition Belt Inspired)

0.2mm layer, 2 walls, 15% infill

0.2mm layer, 2 walls, 15% infill