Hacker News Reader

> the easiest thing to do would be to create the part with the printer, then use it to form a mold for casting the part out of metal

This is definitely not true for parts that need to be closely toleranced. Lost-PLA casting, DIY mold-making, etc are manufacturing processes not world-renowned for their ability to keep things precise.

View on HN

Yeah, most parts in simple designs do not need to be super precise. Some hand fitting might be necessary.

This is in the context of firearms, which are presumably modern repeating firearms, where they will cease to function if the tolerances are wrong.

You can get remarkably far with pretty crude tolerances, especially with lower pressure, pistol rounds. For example a direct-blowback, open-bolt submachine guns akin to what was used in WW2 can be pretty easily designed and built by anybody with a passable understanding of mechanics.

Again, we're talking about casting. Take a look at an Owen or a Sten and get back to me on what parts you think can be plausibly lost-PLA casted.

Reply on news.ycombinator.com