Rotating Drum
The central component of this robotic hand is the spinning drum. This drum has different slots that can hold squares of cardboard in different positions.
Cardboard foundation
Cut a length of cardboard about 16" long and 5" wide.
Use the section of tube you've cut to measure where to score the fold lines. Fold cardboard into a "U" shape.
Cut a pile of cardboard "ribs" the same length as the cardboard tube and about 1/2" wide.
Add a line of glue to the edges of each rib. This line of glue will provide grip to hold small squares of cardboard.
Glue these ribs around the cardboard tube.
Leave a small gap between the edge of each rib, just wide enough to slide a piece of cardboard into.
Test your rotating drum out by sliding some bits of cardboard into the gaps. They should grip the cardboard firmly, but still allow you to slide them back and forth without too much effort.
If you find the grip too loose, add another small line of hot glue to the edge. If the grip is too tight, squeeze the cardboard square to flatten it slightly, the corrugation inside should give it enough spring to still fit tightly into place.
