Thank you for the link, Walter. I did mistakenly say that we were using a +/- 10 psi range but in fact we are using +/- 10% on air pressure. The machines maintain a very even pressure and are maintained and tested by the manufacturer. I have no reason to belive that air pressure is the problem. The screens kick out any under/over size pieces and our shot checks always turn out very good. It seems that when our new machines were installed we just did not know about this variable.
