Racing Spool

thingiverse

In days gone by, you could make a racing spool from an empty thread spool, two nails, a bead and a rubber band. Nowadays, most thread spools are made from plastic and not suitable for such purposes. Besides, it really helps to use rubber bands for tread and it can be hard to keep them on the spool. There are two models here: one a quick adaptation from the knitting spool, the other with modified rims for improved traction (though you'll still want rubber bands for tread). So pick your driver rubber band, build your racer and go! Instructions I printed the spool at 0.3mm layer height as resolution really has no bearing. I also used 4 shells out of concern for rubber band tension, but that is most likely overkill. No supports or raft needed, though the driving arm does tend to peel when just using blue painters tape. Printing directly on the acrylic bed worked beautifully. When printed, thread the driving rubber band through the bead. One end goes around the driving arm, the other through the spool and secured around the posts. Then use two broad rubber bands for tread to improve traction. Wind up, set and go! How well the racer works depends a lot on the rubber band. You want one short enough so that it holds together when assembled and not too thick or strong: a weak rubber band that requires lots of winding will go slower but farther.