Simple chain

UPDATE 10/02/2015

3D printed it and found that 5mm holes in part2 worked much better, allowing better play. Closed the part3 and made a bigger jig. Now you can snap parts together with a 4mm rod without any glue if you're lucky like me and part3 fits tightly on the rod.

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This is a simple chain design that requires some 4mm rod (any kind as long as you can cut it with a hand saw). You can make it as long as you want, design your own ends, etc.

This design comes with a jig that allow