Thumb prosthetic

**(not ready to print yet)**

This is a thumb prosthetic I'm working on for myself that's going to be similar in functionality to Dani Clode's "The Third Thumb" project.

I will work on mounting the thumb to the hand when I verify that the basic functionality of this design works.

The tinkercad project for this is here: https://www.tinkercad.com/things/gNjRRJzxre0.

Let me know if you try making this!

Print Settings

These are just the settings I used, feel free to print however you normally do.

Printer Brand: Creality

Printer:  Ender 3

Rafts: No

Supports:  No

Layer height: 0.2mm

Infill: 20%

Filament: KAIGE PLA+ Black

Post-Printing

The larger hole

The larger hole is for the tendon string (I'm using a nylon string but you can use anything). Simply thread the string through each thumb segment and tie two knots at the top and bottom of the finger to stop it falling off the string. When you pull the string, holding the base segment, the thumb should curl up.

Note: This hole is 1.5mm in diameter

The smaller hole

The smaller hole is for a 0.25mm steel spring wire (something like this 3m piano wire for £1.39). This provides the "bias" force which uncurls the finger when the tendon is released.

Note: This hole is 0.6mm in diameter.