My current project involves a precise sliding motion - low friction but also low slop. One way to achieve low slop would be to dial in my printer to the Nth degree and size the parts “just so”, but I took the alternate approach of making a linear slide with integrated tension adjustment.

So:

1. Print out a slide.stl and a slider.stl
2. Press two nuts into the nut pockets on the bottom of slide.stl
3. Insert 2x M3x15 bolts into through the holes in the slide.stl 
4. Place slide.stl into slider.stl . Spray a bit of lithium grease onto the contact surfaces.
5. Adjust the tolerance by tightening/loosening the bolts

It's probably best to print these in a self-lubricating material such as Nylon.

The slider should be modified to hold whatever you want to be able to slide. The model here allows attachment of a M3 bolt to protrude vertically as well as the metal parts of a terminal block (which I used to hold a fretsaw blade).