Why do you need to retrain? You've got a specific idea to test, just keep exploring the edges of what's possible on a low budget as a side project, and keep your day job. Cultivate friendships and knowledge of equipment at your local hackerspace, and you'll be quite surprised what can be done on the very cheap.
If you want to keep things private, you can get 5 axis desktop CNC machines for about $5000, really good 3d printers for $2000, electronics to measure/control just about anything dirt cheap thanks to jelly bean parts and super-powerful microcontrollers.
If you want to keep things private, you can get 5 axis desktop CNC machines for about $5000, really good 3d printers for $2000, electronics to measure/control just about anything dirt cheap thanks to jelly bean parts and super-powerful microcontrollers.