Just one more thing for the antis to want to ban. They already have draft proposals to require licenses for machinery and tools capable of making guns. A federal license would be required to open a machine shop and only licensed machine shops would be authorized to buy lathes, milling machines, etc. They would also have to keep records of all jobs, with photos of the work and ID of the customer.
See, and you home workshop guys thought you could escape the all-seeing eye of Uncle Sam! No way.