As soon as I made this linear slide: http://www.thingiverse.com/thing:5625

I wanted to make a modification.

There are a couple of challenges with that first design. First, the very large piece is very hard to print and get totally flat. It wants to warp.

Second, the design requires a fixed size separation of the two smooth rods. That's going to be fine for certain loads and directions, and not for others.

So, this thing is a piece of a reinterpretation of that design. This one piece simply captures a 608 bearing, and provides a nice stable piece that can be threaded onto a 5/16" threaded rod.

This thing, in combination with a couple of these other things: http://www.thingiverse.com/thing:5678

Would give you what you need to make a linear slide of any size (length and separation) for an endoskeletal bot.

1) Print a couple of these when creating a linear slide.
2) Press fit 608 bearings into the large opening.
3) Thread the thing onto 5/16" rod, with other components
4) Add other components to your design to complete your linear slide
5) Rejoice!