[drcube]

It's not an "AR-15 lower receiver maker". It's a cheap CNC mill you can do an infinite number of useful things with. Should high quality printers be illegal because you can make counterfeit bills with it? Or is the potential for harm an incidental part of any useful device? You can stab someone with a knife, but they're pretty handy for chopping food, too.

[bryanlarsen]

It is illegal to sell high quality printers that print currency, or at least sufficient pressure has been applied to printer makers so that their printers refuse to print currency.

http://www.cl.cam.ac.uk/~sjm217/projects/currency/

[schoen]

I'm pretty sure that it's a matter of "sufficient pressure" and not legislation in this case, at least in most jurisdictions.