I often find myself needing to clamp large items such as face frames of bookcase counter edge nosings. Unless your Norm Abrams and you have a plethora of various size pipe clamps and a ton of space to store them you often find the need to improvise. That’s why I use gas pipe union to accomplish my pipe clamp extensions.
Pipe Clamp Extensions
When I need to clamp long parts together I use a double threaded union to join two clamps together. I keep [2′, 3′ and 5′] ¾” diameter pipe clamps in my shop and to make a larger pipe clamp I join them with the threaded union. [see photo below]
This trick saves me from purchasing long clamps and them having to store them in my already small shop.