Irwin pipe clamp modified for push/pull.
Bought the Irwin pipe clamp last summer, and disliked the fact that the adjustable end didn't screw on like the Pony and others do. Then the light bulb lit - I could modify it to push as well as pull. So, disassembly time. Picture 1 shows the locking mechanism on the adjustable end, similar to the other sliding end. #2 shows the disassembled clamp. The handle is just a press fit and a little work with a small hammer removes it. A roll pin holds the threaded screw to the movable face, and after driving it out with a pin punch, the clamp can be totally disassembled.
Picture 3 shows the top of the main casting being drilled with a step bit. A small pilot hole was drilled first, locating the center by eye. The part is cast iron, and drills easily. The step drill only opened it up to about 3/4", and a couple S&D drill bits got it to 1-3/32, still too small to fit over a 3/4" pipe. A bit of work with a half round file finished it to where it would smoothly slide over the pipe. Picture 4 shows the casting as drilled.
Alexis de Tocqueville was a very smart man.