I grew up hacking stuff in a machine shop. Now I design military aircraft.
Using a PID temp controller, SSR, thermocouple, and some steel tubing, a cheap fryer from Wal-Mart is now a staple of gourmet med-rare stake cooking.
One of my grandpa's mini model steam engines needed a replacement for a die-cast flywheel that had been destroyed.
I spent a few years restoring a John Deere Model E 3HP engine.
I stuffed a mid-range system into one of those silver suitcases from your local retail hardware store.