In New Zealand we tend to say that "you can make anything out of a bit of "number eight" wire. We were off the grid for the last couple of days, up in the Kaikoura Range, and Heather was missing a crochet hook, so our awesome host offered to make one out of a piece of wire.
Here is the design specification, along with the finished product. It works well, though unfortunately there was no sandpaper available to properly smooth off the rough edges for a good finish.