and that extends transverse between the first and second side plates the tube 123 or the spacer 127 may also prevent the side plates from moving towards one another more particularly in fig6 the pin has two steps 160 and 162 on each end where there is a change in pin diameter the inner surface of the side plate is in contact with the inner step 160 of the pin 134 and prevents motion of the side plate toward the center of the chain or motion of the pin away from the center of the chain the outer step 162 of the pin serves to reduce the diameter of the pin further so that there will not be a press fit with the side plate in the portion of the pin that extends beyond the side plate to make chain assembly and maintenance easier there can or cannot be a press fit between the pin and the side plate between the two steps as desired the bar 170 keeps the two side plates at a fixed distance and prevents relative motion between the pins and side plates instead of the tube there can be a protrusion 127 as shown in fig1 made integral to the side plate which has a face contacting the protrusion from the mating side plate a bolt 178 is still used to keep the side plates from moving away from each other in fig7 the pins.