Les, this is what it written in the description:
Moving jaw has slight inward slant that straightens as pressure is applied
so i assume they dont perfectly mate until a good bit of pressure is applied???
Tod: i heat all three together with a 30 min soak, after 10 minutes i pull one out and quench, ten minutes later another etc! the oven only drops 30 degrees when opening and is back at quench temp in under a minute, so 10 min between each is more then enough. when i quench one at a time i get much better results.