How to Make a Working Model Robot Hand

Note: if you look through the instructions below and decide the project is too messy or complicated, there are two good alternative builds.

First, a brilliant use of "zip ties" for both pulling and spring-back from Curt Gabrielson.

And Joel Anderson sent me this link for a simple animatronic hand.

Important Revision

We've figured out a simpler way to make the back of the hand.

Pattern

You will need a pattern for the hand which you can print out. When you print it out, be sure that image is not scaled bigger or smaller. Do not leave any boxes checked that say "fit to page" or anything like that. Also, measure the scale check; it should be 2 inches or 5 cm.      PDF   

Introduction

Part 1 is and introduction, starting with a science road show to an elementary school where we get kids to start thinking about how their hands work. We make the case that the muscles that move our fingers are not in our fingers! Our fingers are so strong and yet so nimble because strings--called tendons--connect parts of our fingers to big muscles in our forearms. If YouTube is blocked in your school, try this Schooltube link Part 1.

Directions, Materials, Back of the Hand

Note
This method of embedding the strings on the back of the hand is outdated. Please watch the revised version above.

Part 2 actually starts the directions, beginning with a list of all the materials you'll need, then shows how to embed the strings in the silicone on the back of the hand. (See "Important Revision" above for the better method) You can print out the pattern for the hand in PDF format. When you print it out, be sure that image is not scaled bigger or smaller. Do not leave any boxes checked that say "fit to page" or anything like that. Also, measure the scale check; it should be 2 inches or 5 cm. If YouTube is blocked in your school, try this Schooltube link Part 2.

Front of the Hand

Part 3 starts after the silicone on the back is cured, about a day. Then, on the front of the hand you anchor 5 straws in silicone and weave a thin bead of silicone over them. If YouTube is blocked in your school, try this SchoolTube link Part 3

Finishing

Part 4, the final part, is about cutting notches in the fingers to allow bending in 3 places in each finger. Then you thread the strings through the straws, and congratulations! You have made a working model hand with your own hands! And I bet you'll never forget how your hands work If YouTube is blocked in your school try this SchoolTube link Part 4