The photo of the gearing is mounted on its side. The large wheel is called the 'great spur wheel'. The two smaller ones are 'stone nuts' which drive the stone spindles. The wooden teeth of the stone nuts are individually fitted into the iron casting of the wheel, and are held in place by wooden or mild steel pins. This gearing is an example of the common practice of millwrights in meshing cast iron with wooden teeth. (Information from P Baker, December 1950).