How do people cut sharp inside corners, like the triangles shown? This example is cut in stone but I have seen similar features on wooden building blocks.
If we’re talking tight tolerance, you could custom broach it, use a wire EDM, a sinker EDM, or live with a small radius from whatever your smallest diameter endmill is.
For wooden building blocks with larger tolerances it’s a little simpler, likely a scroll saw or bandsaw.
Anyone else, please chime in if you know of additional options!
Can you wire-EDM natural rock? If this were a through-hole instead of indentation, I’d say using an old fashion file or a (mechanical) planer.
Sorry, I am stuck in the metals space and took this as a general question. For the specific situation above, it’s likely a chisel or some kind of masked abrasive blast
On rock or wood, it’d think it’d be cut with chisels, or some kind of hand tool, rather than any kind of machinist’s tooling, but I’m not a mason or a woodworker. (Not a machinist either, I just like making stuff and like following the communities for different skills/disciplines)
Using a custom die is still technically machining. But I have no idea if you can die-sink natural rock…
They could have sandblasted it in
