Simple chain

thingiverse

UPDATE 02/10/2015 Just took my finished prototype off the printer and tested 5mm holes on part2 and it turns out they really do make a difference by giving a better fit and allowing for smooth play. Decided to add a solid finish to part3 with no openings, creating an even larger jig that lets me connect the pieces easily without needing any glue if I get lucky. The design I created is pretty basic and straightforward, requiring only 4mm rods of virtually any type, as long as they can be cut down to size using a handheld saw. One of the best things about this design is how customizable it is - you can build it as big or small as you want, come up with your own special endpieces, etc. I came across some problems with aligning the rods in place at first, but then I created a little jig that helps me cut the rod exactly to the required 22mm length. After cutting all of my new rods down to size, simply slide them into part3 and hold it together securely by inserting and gluing everything neatly into position, like in this picture. Since the build isn't complete just yet, I do anticipate a bit of manual labour including filing and sanding to achieve that perfect finish.