Experimenting with print-ability of a sprocket and classic roller chain. 6 Tooth Sprocket bore is for 5mm shaft, 12 tooth is 1/4" bore. Set screw holes for both is for 6-32 tap X 1/8" set screw. Assembling the chain is a bit tedious, but goes fairly quickly once you get going Something went wrong with the chain files, fixed and re-posted. Chain files fixed and added rollers only file in case some of you need rollers and don't want a lot of extra links. . Added driven 12 Tooth sprocket Up loaded improved links and rollers, Chain test 3 on 8/8/14 Per caster66's comment I combined the rollers and link in "Chain test 4" The rollers no longer roll, which may cause more friction and faster wear. I have seen some commercial chains produced in this manner, they seem to work OK, but are not recommended for high loads or high speed applications as the rollers can't turn and may result in the chain popping off the sprocket. But hey this is an experiment so why not give it a try. Assembly didn't seem to go much quicker but the part about rolly bits is plausible. 08/13/14 material used was ABS, or your choice settings for sprockets; infill=60% raft and supports = OFF Settings for chain: infill=100% raft and supports OFF Note: I print on a glass build plate with Aqua Net hair spray. Chain assembly: Using scrap pieces of 1.75mm filament, mushroom the end of the filament against a soldering iron to make about a 2 to 3 mm diameter head. Measure about 12mm and cut to make link pins. Place 2 links on a pin, then a roller, then 2 more links.. Links should alternate 2 outside, 2 inside. (See bicycle or motorcycle chain) Mushroom the small end till the links and roller are snug but flexible fit, to seal the links in place. Don't worry if some of the pins get welded to the outer link, but its better if they don't. The chain is surprisingly strong considering it's size.