Square for removing a 2" pipe plug

[Frank S]

I started to call it a square peg for a round hole but decided against it.
I decided I wanted to relocate my air compressor but to do this I really wanted to plumb into the opposite end of the tank. In it was a 2" pipe plug with a square hole just over 7/8" and slightly tapered. I figured the fastest way to make a square peg to drive in the hole was to grind away the threads of a large bolt then support the bolt while attempting to turn with a combination wrench.