I printed out and built Emmett Lalish's brilliant gearbox (http://www.thingiverse.com/thing:34778). I thought that the joint between the crank and the shaft was unnecessary so I joined them together. I then created a removable end stopper as it has to be inserted from the other end. I appreciate that the height will be a problem on some printers. This minor mod makes the crank much stronger and more rigid. This really helps when the gearbox is freshly built and is very tight. By the way, I find that the endstop is best printed on its side with supports turned on. It is much stronger when the plastic is laid the length of the peg instead of layers up the peg.