is for this reason that frame 42 is part of a hannifin hydraulic press the rigid mountings just discussed result in properly finished cores which can be assembled into compressors with virtually no air gap rejects in this connection it should be emphasized that 34 air gap 34 failures or rejects at the point of compressor assembly can hardly be tolerated and reject rates of more than about 1 would be completely unacceptable and essentially preclude the use of a process such as the one of the present invention in a competitive high volume production motor industry trials involving cores made by the process taught herein have now also shown that successful practice of the invention with a roller burnisher seems to require attention to and close control of other manufacturing steps that are followed when manufacturing stator laminations and cores for example early trials that were made resulted in non uniform results until finally it was determined that initial punching dimensional tolerances and annealing practices could prevent successful practice of the invention more specifically with cores sized as described hereinabove the bearingizer would flare the bore of the core when the total indicated runout tir of the individual laminations exceeded 0 011 of an inch as measured from the center of the winding slots or bolt hole centers to the bore on the other hand more consistent results were obtained after a lamination die was carefully repaired and reworked so that dimensional tolerances of plus or minus 0 0002 of an inch of the nominal design dimensions were held and the tir between winding slots and bores in laminations made with the reworked die was only 0 003 of an inch cores made from these more accurately dimensioned laminations could.