yesterday I measured the tread on the utility wheels sold here in La Paz: 2cm from beginning of peak, through next trough, to start of next peak. just fired up Python:
>>> import math >>> 2.0 /math.pi 0.6366197723675814
then cheated and googled: it's almost exactly 1/4 inch! I do believe I can make a drill drive for that wheel with just a little brazing.
last updated 2015-11-26 10:00:15. served from tektonic.jcomeau.com