Series of photographs of prototype Malawi Cart

11. The bicycle-wheel handcart chassis. It consists of two frames, each of two planks, having a bicycle wheel sandwiched between them. These frames are held together by the wheel's axle in their middle, and spaced by wooden blocks at either end (see photos 12 and 13), which in this prototype are fastened by four bolts, nuts and washers, clearly visible in the photo. Care is taken to ensure that each wheel is parallel to, and centered within its frame. The two wheels and their surrounding frames are in turn connected to each other by being sandwiched between two planks at either end. These cross pieces are affixed to the wood spacer     blocks by wood screws. Note that the axles are placed close to the   bottom of each frame. The wood here is under compression, and drilling holes there will not significantly weaken the frames. In addition, it raises   the bed of the cart, which in most cases is desirable for ease of use.

12. Detail view of a rear corner of the cart as seen from above and  outside of the chassis. Note the simple but strong interlocking jointing of the rear of the cart body, fastened using a combination of wood screws    and nails. The two planks forming each side are fastened together using clench-nailed cleats, one of which is visible above the tire. The handle is affixed to the lower body plank using two bolts on either side. In this prototype, the handle bolts are deeply counterbored as the only bolts available for this applications were only 2"/5cm long. Note that the upper frame connecting board is fastened to the wheel-frame by means of wood screws penetrating the spacer blocks, but not into the vertical frame pieces themselves. This allows the frame sides to be readily removed should the wheel need to be repaired. It also makes for a stronger side frame as fewer holes need be drilled into these relatively highly stressed frame boards. The floor boards of the removable body were intentionally cut so they would slightly (1/4"/5mm) overlap the inside frames, to compensate for any shrinkage or bowing.