side wall portions of each half of the packer provide dowell and screw means to hold the halves in assembly a jack clamp 84 has parallel extending side walls 86 forming a bifuscated element which matingly fits about the nose portion 82 in assembly as shown in fig3 a threaded stud 94 extends upwardly from the jack clamp 84 an adjusting nut 96 having flats formed thereon to accommodate handling with a wrench is threaded in an interior bore to fit about the lug 94 the adjusting nut has a boss 98 formed on its upper end which is sized to fit within a mating recess 99 fig5 formed on the lower end of clamp plate 58 the boss 98 and mating recess hold the nut 96 in alignment between the clamp 84 and clamp plate 58 and permit rotation of nut 96 on the lug 94 it is noted that channel cut outs are showing at 100 and 102 on the upper ends of packer clamp 84 and packer 74 respectively this forms part of the pathway 52 that extends the length of the packer assembly described above and communicates the channel 50 at the upper end of the upset with the hole 78 on the lower end of the recess portion in the upset referring next to fig5 of the drawings the packer assembly is shown in cross section positioned in the recess on the upset 40 and shows the angular relation of the parts in assembly the pathways 50 and 52 together with adjacent channels and grooves in the assembly parts form a longitudinal passage extending from the upper end of the upset to the hole 78 this passage is formed by channel 50 channel 52 channel position 68 in insert 66 channel.