the volume will remain constant after expansion the length will shrink even more than expansion under tension it is this change in length as the expansion is underway that is employed in the present invention to push out the slips such as 36 and 38 to the wall of the casing across clearance 66 if present this use of longitudinal dimension change to drive the slip allows for greater flexibility to have the hanger 24 get a bite in a wider range of casing inside diameters than was possible in the prior designs broadly stated one aspect of the invention is the ability to take advantage of the longitudinal shrinkage of the hanger 24 when placed under compressive or tensile stress from swaging fig6 a illustrates slips 36 and 38 slip 36 has serrations or other surface treatment 40 so that upon expansion it can preferably penetrate into the wall of the casing 20 the surface treatment 40 can also incorporate hard materials such as carbide inserts or it can be a regular pattern of protrusions or a series of rings or a thread or any other grip enhancing treatment or coating of the exterior of the slip 36 slip 36 is preferably a split ring with a single split longitudinally alternatively the slip 36 can be a plurality of segments held to hanger 24 with a band spring or other retainer that can allow the segments to be cammed outwardly as will be described below in another form slip 36 can be a solid thin walled ring that can be cammed out if space permits by simply yielding or by fracturing in the preferred embodiment slip 38 is identical to slip 36 and is installed in a mirror image manner as seen in fig6 a.