that lining 32 and brake surface 26 will be substantially coincident during operation having equal radii of curvature thus allowing frictional bearing to be uniformly distributed along the length of surface 26 and lining 32 two tensioners 40 further contribute to the uniform braking friction along the length of band lining 32 the axis of rotation 34 a 34 of brake body 15 would be the same axis of rotation preferably of jaw carrier 75 brake body 15 would rotate about axis a responsive to rotation of the jaw carrier 75 portion of power tong 70 axis a would generally represent the center or central axis of a length of drill pipe or the like being held by power tong 70 brake shoe 30 fig1 and 4 5 is comprised of a brake band 31 and a brake band lining 32 attachment ear brackets 34 35 in cooperation with tensioners 40 as will be described more fully hereinafter mount brake shoe 30 to the housing 60 portion of power tong 70 see fig2 openings 36 in brackets 34 35 allow suitable threaded members 44 to pass therethrough and make an adjustable compression attachment of shoe 30 to housing 60 of wrench 70 gussets 37 reinforce ear brackets 34 35 at their interconnection with band 31 which can be integral rivets not shown can be used to affix lining 32 to band 31 keepers 38 39 register shoe 30 with the drum 20 portion of brake body 15 at surface 26 the construction of tensioners 40 and more particularly threaded member 44 and compression springs 42 will be now described tensioners 40 are comprised generally of threaded members 44 compression springs 42 43 and bolts 48 49 tensioners 40 are used in operation to.