are illustrated in  Figure 1-32 . There are two ways in which  bearing surfaces move in relation to each other. One is by  the sliding movement of one metal against the other (sliding  friction), and the second is for one surface to roll over the  other (rolling friction). The three different types of bearings  in general use are plain, roller, and ball.  [Figure 1-33] Plain bearings are generally used for the crankshaft, cam  ring, camshaft, connecting rods, and the accessory drive shaft  bearings. Such bearings are usually subjected to radial loads  only, although some have been designed to take thrust loads.  Plain bearings are usually made of nonferrous (having no  iron) metals, such as silver, bronze, aluminum, and various  alloys of copper, tin, or lead. Master rod or crankpin bearings  in some engines are thin shells of steel, plated with silver on  both the inside and the outside surfaces and with lead-tin  plated over the silver on the inside surface only. Smaller  bearings, such as those used to support various shafts in the  accessory section, are called bushings. Porous Oilite bushings  are widely used in this instance. They are impregnated with  oil so that the heat of friction brings the oil to the bearing  surface during engine operation. A ball bearing assembly consists of grooved inner and outer  races, one or more sets of balls, in bearings designed for  disassembly, and a bearing retainer. They are used for shaft  bearings and rocker arm bearings in some reciprocating  engines. Special deep-groove ball bearings are used to  transmit propeller thrust and radial loads to the engine nose  section of radial engines. Since this type of bearing can accept  both radial and thrust loads, it is used in gas turbine engines  to support one end of a shaft (radial loads) and to keep the  shaft from moving axially (thrust loads).  Roller bearings are made in many types and shapes, but the  two types generally used in the aircraft engine are the straight  roller and the tapered roller bearings. Straight roller bearings  are used where the bearing is subjected to radial loads only.  In tapered roller bearings, the inner- and outer-race bearing  surfaces are cone-shaped. Such bearings withstand both  radial and thrust loads. Straight roller bearings are used in  high power reciprocating aircraft engines for the crankshaft  1-23 Figure 1-32. Radial and thrust loads.  Figure 1-33. Bearings. Roller Bearings Ball Bearings Plain Bearings Plain Roller Ball Straight roller bearing Deep-groove ball bearing controls both radial and thrust loads  No thrust loads Thrust loads Rotating shaft Radial loads only