The pipe clamp: What many people think about when they think clamps for woodworking. They are exceptionally affordable – you buy the a set of clamping fixtures (head & tail piece), then attach them to a length of iron black pipe. A nice feature of the BESSEY “H” series clamping fixture set is their height, the extra high base provides industry leading clearance form the work surface. Clamping fixtures are available to fit 1/2 inch & 3/4 inch black pipe, something to remember is that pipe is sized by its inside diameter (size of hole) not the external dimension. BESSEY. Simply better.