Next step in the bird box project. Bellows and crank. Turn the handle to pump the bellows. This is similar to the type three model I made before but the guide rails will keep the moving plate horizontal as it moves. There’s a problem though.

As the bellows move back and forth the plates twist in relationship with each other.

This is the net for a section of the current bellows design.

My thought was that if I flip every other row side to side, the rotation in the end plates should be canceled out.

Here’s the new layout.

It takes a little long to score the bellows but the end result works perfectly. No rotation at all!

Here are the two test bellows side by side. Next step – connecting up the crank.