The American tradition of tinkering -- the spark for inventions from the telephone to the Apple computer -- is making a comeback, boosted by renewed interest in hands-on work amid the economic crisis and falling prices of high-tech tools and materials.

The modern milling machine, able to shape metal with hairbreadth precision, revolutionized industry. Blake Sessions has one in his dorm room, tucked under the shelf with the peanut butter on it.

The...