This instructable will show step by step how to build this hand, with wires that when pulled, flex the fingers or palm. The longest part for this project was designing the hand itself, so for the sake of simplicity, the stl files for the hand will be included with this tutorial.
Step 1: Material Gathering
melting (soldering) iron
3D printer + filament
1/16 inch thick nails (at least 16)
thin bungee cable
thin fishing cable
two pen springs.
Step 2: Print Out Parts
1. Print one of each five different palm pieces.
2. Print five finger tips.
3. Print one of the pinky lower and pinky middle parts.
4. Print three of the index lower and two index middle parts (one index lower will be used for lower thumb).
5. Print one of the middle lower and middle middle parts.
6. Print twenty-eight of the washers.
Step 3: Creating the Fingers
1. Sand the top of the digits (optional).
2. Align the digits into a row, aligning the axle holes.
2. Run a nail through a washer, a finger joint, and another washer (repeat for each joint on the finger).
3. Melt the washers to the digits.
4. Cut the sharp point of the nails as flush as possible to the washer.
5. Repeat for each finger.
Step 4: Assemble Palm
1. Cut two nails such that the flat side is removed.
2. Glue the nails to the axle hole on the palm-thumb piece.
3. Melt the lower palm and hole piece with the palm thumb piece's nails inside the axle holes (pictures 2 & 3).
4. Place springs in the ring and pinky palm pieces, and insert pieces using the holes on the lower palm piece.
5. Run fishing wire through the the lower palm piece using the holes shown, and tie a double knot to keep the wire in place (picture 5).
6. Run fishing wires through the bottom of the palm to allow thumb rotation (picture 6) .
7. Run bungee cable through holes to keep palm in outstretched position, and tie knots to keep the cable in place (picture 7).
Step 5: Assemble Hand
1. Place each finger into it's slot, using nails to hold the fingers in place.
2. Run bungee cable through the back of the fingers in order to lock them in an outstretched position.
3. Tie knots in the cable and use glue to keep knots in place.
4. Cut off excess cable.
5. Run fishing wire through fingers and into palm, letting the ends hang out of holes in the bottom of the palm (picture 3 & 4).
Step 6: Use Hand
Separate different pairs of strings, so that when they are pulled, the hand will flex a finger or the palm.