I am assuming these tank tracks will bite into sand and snow, probably ideal for a machine that is apx 12 - 18 inches long and at least 6 inches wide. And I assume they can take a fair bit of weight, and can tackle rough unlevel terrain . When I get a pair finished I will be able to confirm this... I'd love to see what these can do in the sand. Project so far : Tracks are complete , now need motors that match good. If I had to start over I'd leave out idlers and just put a tensioner in the centre of the tracks, simpler and less materials/cost. Testing : running at full speed on my drill for several minutes each side the tracks are holding up well, seems they can take alot of spinning with no problems. You will need skateboard bearings , same as the mendel-prusa uses , upto 10 of them would be ideal . This Project uses 5/16" threaded rod. Print 2 , 4 , or 8 links at one time... Also you can drill or melt with heated paperclip, the side holes on the track-links. I melted the holes on mine. ... I'm using paperclips for bolts , they go all the way across so sprocket v2 catches on them. If you use bolts I'd suggest size 6-32 at 1 1/4 inch length. I'm going with 32 links per track , seems to be the length I want. You can use the sprocket-v2 as an idler or two. (32 links 4 sprockets per track on mine) Each link costs about 1.25Meters of plastic (3mm) (Depends on infill settings) If you get testing these yourself , please post a comment I'd be interested in knowing your results.