Why is there a small anvil-like thing cast into the top clamp piece? It seems like its there to hit with a hammer? Why would that be necessary?
I asked that question on another forum a year or so ago, and someone pointed out that the little bump is level with the clamp head at the bar end, so that, if you set the clamp on the floor on its head, it won't fall over as easily. Once I understood that, I noticed they appear on a lot of different makes of clamps, but not, for some reason, on products of the Adjustable Clamp Company (Pony, Jorgensen). Pony bar clamps will, in fact, fall over when set on their heads, which can trigger the environmental hazard of the air turning slightly blue if you're in the middle of a glue-up when it happens.