I bought a set of Irwin parallel bar clamps a while back, and noticed that the fixed head is not square to the bar. They lean in about 5 degrees or so. Of course, this means that the jaws are in fact, not parallel. I wrote to Irwin, and some guy told me that they are supposed to lean slightl inward to prevent slippage. Anybody else experience this? Doesn’t seem right to me. My Bessey’s seem square.