Instructables
Picture of Mechanical Hand

Students will make a simple mechanical hand with a trigger connected to a hinge. Once complete, students can test the ability of their hand by trying to pick up as many straws as possible. Extra class time (and there should be plenty!) can be devoted to further testing and redesigning to make the best mechanical hand possible!

 
Remove these adsRemove these ads by Signing Up

Step 1: Materials

For this design, you will need:
(and extra for redesigning)

15 Craft sticks
Craft cubes
Round cube beads
Part of 1 Straw
2 Skewers
2 Rubberbands
Tape
Hot glue

And a box of straws for the challenge!

Step 2: Build the hinge

Picture of Build the hinge
P1040424.JPG
P1040425.JPG
Cut two 1/2-inch pieces of straw. Wrap tape around the end of a skewer and thread the round cube beads and the straw pieces onto it as shown. Wrap tape around the other side and cut off the excess. 

The straw pieces act as spacers to prevent the fingers from colliding.

Step 3: Make the fingers

Picture of Make the fingers
P1040433.JPG
P1040434.JPG
P1040435.JPG
Create the center finger as shown in the picture. The half-sticks are glued onto the side of the cube at a 45-degree angle.

The two other fingers are built similarly on either side of the center finger. Make sure that the half-sticks on the outside fingers are glued on at an angle that is inverse to the center finger.

On the 'back' of the hand, glue a half-stick to the two outside fingers. These two fingers will be actuated at the same time.

Step 4: Make the arm

Picture of Make the arm
P1040430.JPG
P1040442.JPG
P1040443.JPG
The arm is an extension of the center finger. Sticks are glued together with at least 1-inch of overlap to ensure a nice strong bond. The arm can be any length, but longer than 6 or 7 sticks is not recommended because it is more difficult to lift objects that are further away from your body. The arm also may not be able to support it's own weight if it is extremely long.

Once the arm length is determined, add a handle and a thumb rest at the end. The handle and thumb rest that are pictured are very minimal - there is a lot of room for innovation and customization.
ericesquivelbr made it!1 month ago

It was great to do it, and I made one only enhacement, that I took a picture. Thank you... I have a lot of fun...

image.jpgimage.jpg
WYE_Lance (author)  ericesquivelbr1 month ago
Wow, this is awesome! Thanks for sharing - it's really cool to see others actually make use of these project plans :)
mohesh5 months ago

extremely awesome

TTSS5 months ago

Simply Wonderful.

That's awesome

Awesome! This would work great for a puppet hand :D thanks for sharing!

rimar20006 months ago

Good work! Maybe you could add a video.

audreyobscura6 months ago

So great!! Thanks for posting.