Knick's finger, v2.0

thingiverse

Update: For the latest design, please check out: http://www.thingiverse.com/thing:904304 This is version 2 of my prosthetic finger designs, which work well for individuals that are missing the last 2 segments of a finger, but still have a short stump. I can provide Sketchup files or export in another format if helpful to anyone. Here it is in motion: https://www.youtube.com/watch?v=iSYBMSrvFLY Thanks to the great folks who have been working on 3d printed prosthetics longer than me who gave inspiration and ideas. Please contact me if you need any help on finger prosthetics for yourself or someone in need. Instructions I print the socket with NinjaFlex, and then the parts with PLA. The PLA cleanup is pretty standard, be sure that all holes are smooth, and hinges fit cleanly with enough clearance. In the next revision I'll clean up some of the tolerances a bit. I print everything with support, you might be able to get by on some parts without it. For the socket, a quick pass of the inside with a Dremel sanding drum does wonders to clear that out. I use PLA for hinge pins, with caps that put on the ends for a clean look and positive closure. Just cut some filament a bit longer than you need, melt the end briefly with a lighter / soldering iron, and squish the cap on the end. Same elastic as most hand projects use, but I prefer 50lb braided fishing line for the tendon. It needs to anchor to the other side of your wrist, so that bending the wrist does not move the finger, only moving the stump does. For this I use a bracelet which the tendon anchors back to. I use a small jewelry clasps (cheap on amazon) to connect the tendon to an aluminum turnbuckle from an RC car, allowing for easy adjustments of tension. I really like how the turnbuckles work and look, but they are a bit pricey, so in another revision I'll come up with something printable for that part too.