Thanks, that’s really helpful. I suppose it makes sense that not just material but cut size and bit would matter. They usually focus just on the geometry on YouTube.
Out of curiosity, what’s the lowest you’ve ever gone? It’s hard to picture machining happening at something like 60RPM.
If you want to get that through steam or electric motors or whatever that’s up to you
Since I’m interested in technological bootstrapping more generally, I think most about water wheels, actually! Steam engines need to be machined, which is a chicken-and-egg problem (or I guess crafted freehand to a machining-like precision, like Vaucanson’s lathe). Electric motors don’t necessarily, but they need a source of electricity, and that’s either a lot of batteries or another rotating power source, which again doesn’t solve the problem.
Waterwheels can be made with hand tools - maybe even primitive tools - and can achieve surprisingly modern efficiency and power density. They do require the right topography, but then again they spin indefinitely without needing to be fueled. 50hp is still a sizable wheel, near the top of what existed in pre-modern times, but I’m guessing you can do basic things with an underpowered machine.
You’d be surprised how slow machining can be. Cutting speeds are all in sfm (surface feet per minute) and when you have a BIG part, them feets add up quick. Check out videos of big old vertical lathes running big parts. You can get down to a quarter of an rpm but the flange or fitting is so fucking huge that you’re still pushing 100-200 sfm at the bit.
Thanks, that’s really helpful. I suppose it makes sense that not just material but cut size and bit would matter. They usually focus just on the geometry on YouTube.
Out of curiosity, what’s the lowest you’ve ever gone? It’s hard to picture machining happening at something like 60RPM.
Since I’m interested in technological bootstrapping more generally, I think most about water wheels, actually! Steam engines need to be machined, which is a chicken-and-egg problem (or I guess crafted freehand to a machining-like precision, like Vaucanson’s lathe). Electric motors don’t necessarily, but they need a source of electricity, and that’s either a lot of batteries or another rotating power source, which again doesn’t solve the problem.
Waterwheels can be made with hand tools - maybe even primitive tools - and can achieve surprisingly modern efficiency and power density. They do require the right topography, but then again they spin indefinitely without needing to be fueled. 50hp is still a sizable wheel, near the top of what existed in pre-modern times, but I’m guessing you can do basic things with an underpowered machine.
You’d be surprised how slow machining can be. Cutting speeds are all in sfm (surface feet per minute) and when you have a BIG part, them feets add up quick. Check out videos of big old vertical lathes running big parts. You can get down to a quarter of an rpm but the flange or fitting is so fucking huge that you’re still pushing 100-200 sfm at the bit.