Linear slides

[Gui Cavalcanti]

I've seen a couple of teams use Bosch extrusion or 80-20 to make accurate linear slides. I was wondering how the slider actually worked, or if you didn't use either of those, how you made yours work?

We've only made three real efforts at linear slides. The first was a cylinder-in-a-cylinder which worked well. The second was sandwiching a piece of aluminum extrusion between two pieces of HDPE, which didn't work well at all. The third was to cut a giant track in a piece of solid aluminum, stick in a smaller piece of aluminum, and guide the smaller piece with dowel pins in two slots cut in the exposed sides. That gets a bit iffy, because it's a lot of machining for relatively little gain.

Any thoughts?