Can't speak on the subject of open end wrenches, but I've seen bigger pipe wrenches; I watched a couple of fire sprinkler fitters assemble a sprinkler system once, using six-foot pipe wrenches. No idea of the weight, but they did take turns: one guy would stand on the "holding" wrench, the other would operate the "turning" wrench, switching off every ten minutes or so.
Their boss sent them with the wrong tools. We had combination pipe wrenches for the big pipe. They're Ridgid, but the handle & head have a joint between them, and a clamp attached at that joint. Clamp on the pipe, wrench on the fitting and no hold back wrench needed.
I had two different "old hands" tell me that I couldn't make pipe tight enough - Once was at a Hilton on 2" threaded. I couldn't get into position so I reached my arms out, pulling like I was clapping with arms outstretched. The second time I was making up a drop with a 10 inch pipe wrench. Both times the "old hands" went in to show me how to do it. Both times they didn't budge the pipe, and both said exactly the same thing "Well, you are a pretty big boy."
Tony is a fitter I've known since he was a cub 25 yrs ago. He was constantly breaking 10" Channellock's. He made up pipe with those so tight everyone else needed either an 18" or cheated 10".
So biggest wrench? Depends on the horsepower.
Capacity of the Williams is only 7-3/4". So what constitutes big - length? Weight? Capacity?
Mechanical advantage would be my criteria - The biggest wrench is the one that delivers the most work, consistently. Based on the same input force.
The winner would be, unless compounded, would be the longest one that was sturdy enough to do a job without failing.
Chilly
