Phantom Pain Functional Prosthetic Hand by Armatus

Last crawled date: 3 years, 1 month ago

Several months ago I received a commission to create a functional prosthetic hand based off of the Phantom Pain hand used in Metal Gear Solid 5. This was for a client who was born without a left hand and grew tired of his standard claw style prosthetic, but didn't want to shell out thousands of dollars for a motorized medical grade prosthetic. The goal was to create something durable, functional and useful on a budget. This is what I came up with. My client has very little left of his wrist, meaning the standard active grip system on other 3D printed prosthetics wouldn't work for him, so I designed a passive grip system using retention springs. This allows the fingers to (more or less) auto-adjust to whatever object they are gripping, and only requires user input to actually open the grip, which is done by pulling the knob at the rear of the forearm section. All 5 fingers normally open and close at once, but there is also a detachable ring connected to the main knob which articulates just the index finger, which can be locked in place to allow greater usability in actions such as typing and pressing buttons.
I'm releasing these files for free because I want them to get into the hands of other people who actually need a prosthetic and can use them to better their lives. The total material cost for the final device is under $100. Here is a breakdown of the additional parts you will need:
Order these;
14x Low profile 4-40 Locknuts: https://www.mcmaster.com/#catalog/122/3213/=15s86hk
50x 4-40 7/8" screws: https://www.mcmaster.com/#catalog/122/3018/=15s87ym
20X 4-40 5/8" screws; https://www.mcmaster.com/#catalog/122/3018/=15s89ba
14x Torsion springs (option to use stronger springs here for increased grip strength, I used 0.353 OD 270 degree right hand torsion); https://www.mcmaster.com/#catalog/123/1293/=1ayad1u
10 feet of 1.2mm stainless steel braided cable; https://www.amazon.com/gp/product/B00GYTWM4I/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
Normal hardware store stuff;
1x 6-32 Locknut
2x 6-32 40mm screws
2x 6-32 15mm screws
12x 13mm rubber grip pads
7 10mm rubber strip grip pads
Super Glue (for holding the pads in place)
Epoxy putty (For filling the connection between the cables to the pull knob)
Preferred type of foam for internal padding (high density open-cell foam recommended)
Assembly is pretty self explanatory, all parts press fit together (may require some sanding depending on the accuracy of your printer and slicer) and then are screwed into place with the appropriate size/length screw as listed above. The springs are slotted into the appropriate ends of each finger joint before they are put together. The steel wire must be knotted at one end, and then slid through the holes of the fingers to the back of the wrist starting at the finger tip. Please don't hesitate to ask any questions or ask for modifications :)
EDIT: All step files have been posted. Feel free to modify the files however you please, and be sure to post remixes for the community to benefit from!