Here is a tool that I use quite often and is easily made. I use it to control the temperature of my $5 soldering iron so I can solder wire or circuit boards easily. I also use it to weld plastics and even run a transformer for my foam cutter.
It is constructed with a standard receptacle and a light dimmer. The top half is straight 120v for a dremel, light or similar tool. The bottom half is regulated voltage that I plug the soldering iron or transformer in to. The receptacle is split by breaking the tab in the middle that connects the top and bottom halves on the hot side.