After many little pieces, I am finally able to construct a delta robot that is mostly made of printed parts.
This thing is a delta robot frame. There is the basic frame, mounted motors, arms, tool holder, and the like. The arms closest to the motors are printed plastic notched spans. The longer arms are wood dowels, with tape on their ends to enhance the friction fit into their fittings.
Steel rods in this case are 5/16". The size doesn't really matter, you can select any size as long as the vertices match.
the size is 2' on edge. that's a pretty huge build area if you decided to use this robot as a 3D printer.
It's a good platform for experimenting with various delta robot ideas. The arms will be replaced with carbon fiber. The 'bearings' will be replaced with brash, with 1/4" axles, the motors will be replaced with servos, etc.
At any rate, at least a model can be built, with not too many different types of materials. There isn't a fastener on the whole thing. Of course if it were actually moving, you'd probably find places where you'd want some fasteners, but that's the whole point of the experiment anyway.
Some interesting aspects of the design:
This is an endoskeleton. It can take a 'skin', but it's not required for structural support.
The tetrahedron is a fairly stable self supporting structure.
No threaded fasteners, other than the threaded rods themselves
Use zip ties to hold the little motor board in place. That board could be gotten rid of entirely if the motors mounted to the rod instead
Changed male and female clevis part counts. They were 24 ea, and they should have been 12.
Created a page on RepRap as this is more of a development project than I think is appropriate for Thingiverse
There have been many parts updates. I've included a new picture with the servos and new arms, as well as the base plate in place. I've added a video on YouTube of the thing in action: http://www.youtube.com/watch?v=VzWJDWvJvqo
1) Decide how big you want your bot to be, and what diameter of rods you want to use.
2) Cut 6 threaded rods to the same size. If you pick a standard size that your supplier carries, you won't need to cut anything.
3) Print all the little bits and pieces of plastic you need.
4) Snap and slide them together
5) Put motors into motor clips
6) Put motor mounts on the triangle shaped board
== There are holes in the board so you can fasten to the rods
7) Use zip ties to fasten board to rods
8) Put arms on motors
This is of course a very abbreviated instruction, as the actual instructions could take a while, and require some pictures. My hope is that the design is so obvious and symmetrical that you could figure it out from just looking at the picture.