I have decided to use UHMW, which is a hard plastic, to make the drive sprockets and track treads out of. And other stuff later on. You can get remnant/scrap pieces, ($1 per pound in my case), which is a very fair price… after all, it’s plastic, not lead.
Why UHMW? It is a thermoplastic polyethylene. It has the “highest impact strength of any thermoplastic presently made.” It has very low friction (less than nylon and acetal, and is comparable to Teflon), is self-lubricating, and is highly resistant to abrasion. It is odorless, tasteless, and nontoxic. It is also very resistant to water, moisture, most chemicals, UV radiation, and micro-organisms. *
Basically it’s super tough. BUT, the other great feature, is you can cut it with most woodworking tools… about the only thing you don’t wanna do is sand it with sandpaper. I was also able to get it in black, which is nice, will give the tracks a nice realistic look.
I got 1/2″ thick for the treads. I decided I will cut them 1″ wide, and I think the 1/2″ will be perfect… I had originally said 1″ thick, but I think that is overkill… it would weigh twice as much, and would dig or catch more into soft ground, which should not be necessary.
For now, I cut out one drive sprocket, just need too clean up the edges a little:
* – Copied verbatim or paraphrased from http://en.wikipedia.org/wiki/Ultra_high_molecular_weight_polyethylene