One of the more interesting tasks is fabricating our handcar axles. On a conventional car the axle is a solid round rod. This is not an efficient design as it makes the car quite heavy. For the touring handcar we use a hollow axle that is made by using a tube in the center, with axle stubs on each end. To accomplish the combining of pieces, liquid nitrogen is used to freeze the axle pieces so they shrink just enough to fit into the tubes. There is only a few seconds of work time before the stubs expand, locking them in place.