All project files can be found here: https://cad.onshape.com/documents/7c265efa9d5612eb994e2e4a/w/06e95e783c6efd3a7cc0f7ef/e/e13c9a3a0cc5a1ef48cadb6a
In order to make printed motor driver sprockets/pullies work, I’ve purchased a 8mm to 1/2" hex adapter and pressed/locktighted it onto the motor shafts. This is the one I’ve been using: It’s from AndyMark and can be found here: http://www.andymark.com/8mm-Keyed-Bore-1-2-Inch-Hex-Adapter-p/am-0588.htm
VexPro makes a cheaper version, but it has been on backorder for a couple of months: http://www.vexrobotics.com/vexpro/hardware/217-3255.html
My hub adapter was inspired by brentyi’s on thingiverse (http://www.thingiverse.com/thing:545345). It is a complete redraw using this grabcad file designed by andrew: https://grabcad.com/library/flywheel-skateboard-wheel-clones-1
I’ve replaced the bolt/nut attachment system with a simpler Spax screw system and it holds very well.
This is the HTD-5M version:
The above pullies are printed in trimmer line nylon and don’t seem to wear at all.
This is the #25 sprocket version:
I’ve been pleasantly surprised by the durability of these printed sprockets. The wheel sprocket in the above pic is trimmer line nylon and has over 60 miles, while the motor sprocket is eSun PETG and has approx 30 miles. Obviously, these sprockets will not outlast the chain, but they seem to be holding up and should last at least to an average wheel rotation interval.