several types of steel fasteners. Cotton duck belts usually used metal fasteners or were melted together with heat. The leather belts were run with the hair side against the pulleys for best traction. The belts needed periodic cleaning and conditioning to keep them in good condition. Belts were often twisted 180 degrees per leg and reversed on the receiving pulley to cause the second shaft to rotate in the opposite direction. Pulleys were constructed of wood, iron, steel or a combination thereof. Varying sizes of pulleys were used in conjunction to change the speed of rotation. For example, a 40" pulley at 100 rpm would turn a 20" pulley at 200 rpm. Pulleys solidly attached ("fast") to the shaft could be combined with adjacent pulleys that turned freely ("loose") on the shaft (idlers). In this configuration the belt could be maneuvered onto the idler to stop power transmission or onto the solid pulley to convey the power. This arrangement was often used near machines to provide a means of shutting the machine off when not in use. Usually at the last belt feeding power to a machine, a pair of stepped pulleys could be used to give a variety of speed settings for the machine. Occasionally gears were used between shafts to change speed rather than belts and different-sized pulleys, but this seems to have been relatively uncommon. History Early versions of line shafts date back into the 18th century, but they were in widespread use in the late 19th century with industrialization. Line shafts were widely used in manufacturing, woodworking shops, machine shops, saw mills and grist mills. In 1828 in Lowell, Massachusetts, Paul Moody substituted leather belting for metal gearing to transfer power from the main shaft running from a water wheel. This innovation quickly spread in the U.S. Flat-belt drive systems became popular in the UK from the 1870s, with the firms of J & E Wood and W & J Galloway & Sons prominent in their introduction. Both of these firms manufactured stationary steam engines and the continuing demand for more power and reliability could be met not merely by improved engine technology but also improved methods of transferring power from the engines to the looms and similar machinery which they were intended to service. The use of flat belts was already common in the US but rare in Britain until this time. The advantages included