I've been following very specific instructions to make a car jack (scissor jack) assembly. At this stage, I should be able to spin the crank handle by clicking and dragging - however, I can't. Unsure where I'm going wrong as I've checked and re-assembled many times according to the instructions. Crank handle is mated so that it is aligned with the lead screw and parallel with the right plane of the assembly so that it can spin in one axis only. If anyone has time to take a quick look and suggest where it is I'm going wrong, I would be very grateful.