I've done the first, and get good results with aluminum, brass, and both mild and stainless steel (although stainless is probably pushing the limit here). Your

I've done the first, and get good results with aluminum, brass, and both mild and stainless steel (although stainless is probably pushing the limit here). Your anecdote + my anecdote don't equal data, but your use of absolutes -- specifically "the only way" is incorrect. It can be done, and many have done exactly that. Also, your magic $10k price-point mill doesn't include the cost of tooling, or workholding, or CAD/CAM software, etc. So now you're just reaching for anything to inflate the cost back up to your number.