Too Much Faith in Your Tripod

The TriMax I have has screw clamps -- the kind with the big black knobs -- and I noticed that they seem to bottom out when tightening the legs. I even went so far as to run a die down the bolts to extend the threads a bit, but it still seems like the screws hit the end of their travel. I've never had a leg slip, it just seems like the clamp should tighten before the screw runs out of thread. Maybe I'm imagining things...