stop ridge 26 which is circumferentially disposed about the outer surface of midsection 24 beneath upper stop ridge 26 a substantially smooth lock ring slide section 28 and immediately beneath slide section 28 a lower lock ridge 30 of an essentially triangular cross section circumferentially extending outward from the outer face of midsection 24 immediately beneath midsection 24 of packing mandrel 20 the external diameter of packing mandrel 20 is enlarged to equal substantially the overall diameter of the entire m x lock creating lower sleeve section 32 within lower sleeve section 32 is found a lower shear pin apperture 33 lower sleeve 32 terminates at lower sleeve base end 34 which forms a support for a series of chevron sealing packers 36 the overall mandrel 20 terminates at the lower end of lower sleeve section 32 in api pin section 38 which is adapted for supporting other pipe tool or sub sections within a made up drillstring mandrel 20 and sleeve 12 form a coaxially disposed structure the exterior of 2 is formed by a third coaxial cylinder member locking dog sleeve 48 locking dog sleeve 48 is substantially a coaxial cylindrical structure enclosing sleeve 12 and mandrel 20 it is connected at a lower end by means of lower threaded connections 50 to a mating threaded connection 50a on lower sleeve member 32 it will thus be seen that the combination of sleeve 48 and mandrel 20 form a single connected structure coaxially enclosing expander.