First: A metal plate is only a few cents more, if you're so determined to do something like this.
Second: why not just use a female in-line rubber connector instead of a box like that?
It will take knocks better and is designed for "home-made" cords or repairing the ends on extensions. The steel-armored ones are even better for heavy duty use.
Not to mention it's probably much much cheaper than a box, plus strain relief, plus socket, plus cover-plate. Not to mention a couple of bucks for a roll of 'lektrishun's tape...
It would make Joe ... less mad....maybe.
[This message has been edited by SvenNYC (edited 03-10-2003).]