This is a printable linear bushing derived from Triffid Hunter's LM8UU at http://www.thingiverse.com/thing:13631 and edited
to match the standard LM6UU bushings.

This is derivative of Triffid Hunter's LM8UU at http://www.thingiverse.com/thing:13631 Look there for more information.

I added the LM6UU measurements, and allowed for 60 degree opening, and made a module for a plate of 12.

I am trying this bushing while I'm assembling Whosawhatsis RepRap Wallace from http://www.thingiverse.com/thing:14208

Those pictured were printed undersized (~10.8mm vs. design OD of 12mm), and fit loosely within the Wallace sockets. I've wrapped them with paper so they do not slide out, but it isn't ideal. After pushing the bushings along the length of a ground 6mm bar a few times, they seem to slip OK.

The open slot option is for possibly using it in a pillow block for a supported bar in a bed from an old scanner. Or mostly for me playing with learning OpenSCAD.

Triffid Hunter has an updated LM8UU, controlling the perimeter thread width and leaving the inner space hollow for added springiness. You may want to look at those bushings at http://www.thingiverse.com/thing:16813

You can get an LM6UU-sized bushing from Triffid's v3 parametric code at http://www.thingiverse.com/thing:16813 by using:

//LM6UU
lm8uu_od = 12;
lm8uu_length = 19;
lm8uu_id = 6.1;