A very handy wrench can be made from a piece of square bar, shaped as shown and fitted with a handle. The joint at A may be halved and riveted or a weld made as desired. The size of the bar and the space between the parts will depend on the size of nuts to be turned.

The Sloping Notch in the Wrench Permits Its Use on Nuts of Various Size

Ill: The Sloping Notch in the Wrench Permits Its Use on Nuts of Various Size