There's a difference of opinion among the handymen that I meet about which way to use a Crescent on a nut. Of course a ring spanner or socket set is the preferred tool to use, but sometimes the right size tool is not available. If you need to undo a large nut in a remote area where you can't backpack your 1000 spanner set, sometimes you just have to use an adjustable spanner commonly known as a Crescent even though they didn't invent the damn thing.
Now many years ago my old workshop foreman told me to put the spanner on so that the turn is towards the fixed jaw of the spanner. He says that it puts less strain on the moveable jaw because the corner of the nut has less leverage when it's on the inside of the the jaw. And I believe him. This is of course for a heavy load, otherwise it doesn't matter much.
Here's the right way:
Can anyone find any other authoritative cites?