Bearings Small - Print-in-Place, 5 Sizes: 685, 687, 689, 629, 608

<h3>Small Slide Bearings</h3>

This is to complement my earlier release of <a href="https://www.thingiverse.com/thing:4821342">roller bearings</a> with <b>a set of (even smaller) slide bearings</b>. In essence they serve the same purpose but are just too small to print as roller bearings and nevertheless work just great. They come in five common sizes <b>from pretty small (22 mm) to tiny (11 mm): 608, 629, 689, 687, and 685.</b> They are actually easier to print than roller bearings and with a little grease work just like their bigger counterparts. They are all print-in-place, which means that you only need to print a single piece and that there is no assembly involved.

This set starts at 608 as the biggest size, which is pretty much the most commonly used size in DIY projects (filament guides, spool holders, <a href="https://www.thingiverse.com/thing:4843825">fidget spinners</a>, RC cars, robots, perpetua mobilia...), and goes down to 685, which I use in mechanical clocks, robots etc.

Once again they come in <b>five different sizes, and two/three flavors</b> - narrow (named tolMin), wide (tolMax) clearance, and ultra narrow (tolUltra - only the 2 bigger bearings). Please see below for clearance. Measures are inner x outer diameter x width:
- <b>608</b>: 8 x 22 x 7 mm (0.31 x 0.87 x 0.28") - see here its <a href="https://amzn.to/4gzxtg0">steel counterpart</a>
- <b>629</b>: 6 x 19 x 6 mm (0.24 x 0.75 x 0.24") - <a href="https://amzn.to/4ftIaix">and its steel…