Hmm, the shear values are influenced by various factors. First, the shape of the connecting zone (groove) must be correct. In the crimping process, the quality of the knurling plays the most important role. This in turn depends on the quality of the knurling wheels and the correct setting of the knurling machine. The rolling force also has an influence. Here the ideal average values must be found. Too little rolling force may not be sufficient to close the hammer properly. Too much force can destroy the knurls and thus counteract an increase in the shear strength.