properties of the deformable member 16 in turn react against the force of the protrusion 26 and force the split ring 20 radially outward to frictionally engage the interior surface 23 of opening 12 in the manner the preform support device is frictionally engaged with the preform 8 in the example shown in fig5 the split ring is move radially inward to a greater extent than in the example shown in fig4 the protrusion 26 allows the split ring 20 to expand and compress to a greater extent and engage a variety of performs of different sizes the split ring 20 may be compressed until the inner surface 24 of the split ring 20 abuts the shaft 10 alternatively the size and characteristics of the protrusion 26 groove 14 and deformable member 16 can define the extent to which split ring 20 can move radially inward thus a preform support device having the design described above can accommodate preforms that have an internal diameter ranging from slightly smaller than the outer diameter of the preform support device when the split ring is uncompressed to a diameter that is slightly larger than the outer diameter of the preform support device when the split ring is fully compressed the device can accommodate variations of greater than about 0 006 inches in the size of perform openings and also variations greater than about 0 012 inches the size of the gap between the split rings the extent to which the protrusion extends from the back surface of the split ring and the characteristics of the deformable members can all be dimensioned and selected as necessary for a particular application accordingly a preform support apparatus that can accommodate preforms having openings of varying diameters is provided the preform apparatus automatically adapts to the.