cobalt 0 2 percent molybdenum 0 1 percent copper 0 1 percent and chromium 0 1 percent another material which can be used for coating by spray welding is the nickel chrome alloy tafaloy nickel chrome moly wire 71t manufactured by tafa technologies inc tafaloy nickel chrome moly wire 71t is an alloy containing the following elements nickel 61 2 percent chromium 22 percent iron 3 percent molybdenum 9 percent tantalum 3 percent and cobalt 1 percent various combinations of the above alloys can also be used for the coating spray welding packing support areas 131 132 can also be coated by a plating method such as electroplating the surface of support areas 131 132 can be ground polished finished to a desired finish to reduce friction and wear between support areas 131 132 and packing units 305 415 fig4 is a perspective view of a sleeve 150 clamp 600 and torque arm 630 which can be incorporated into swivel 30 fig5 is an exploded view of the components shown in fig4 fig6 is a cutaway perspective view of swivel 30 fig7 a is a sectional view of swivel 30 taken along the line 7 a 7 a of fig6 fig6 is an overall perspective view and partial sectional view of top drive swivel 30.