I found that if your motors run hot, and your gear is printed using PLA, the set screw can loosen because the gear warps a little. This is a Bad Thing(tm). To address this, for people with the right tooling (e.g an M3 tap, a 2.5mm drill bit and a hand-drill), I added a slot for a nut into which you pre-drill a hole and tap a thread for the setscrew. I also made a depression for the setscrew head so that it does not protrude from the hub of the gear. This allows it to be installed inside the mounting hole of the wades carriage if this is necessary to mesh properly with the large gear on the hobbed bold.

1. Drill and tap a hole in a nut that snugly fits your motor shaft. I used an M3 tap and an unknown nut that was lying around. The hole was drilled with a hand-drill.
2. Print the thing.
3. Press the nut into the gear whilst it is still warm (making sure you align the tapped side with the hole in the gear.
4. Cut the setscrew to the right length.
5. Press the gear onto the shaft (you have filed a flat right?).
6. Install the setscrew and tighten as tight as you like (Not just as tight as you think the plastic will withstand).
7. Enjoy a slip free un-stress-warped small Wade's gear.