Threads are a strange case, I am convinced US standard threads are better than metric threads. However this is not because US customary units are any better tha

Threads are a strange case, I am convinced US standard threads are better than metric threads. However this is not because US customary units are any better than metric units but because whoever came up with metric threads messed up. In short after a lot of math it boils down to the fact that US threads are defined as threads per unit. and metric threads are defined as units per thread. "So what" you may say, "6 of one, half dozen of the other", but threads per unit ends up having a lot of common factors and can be cut easily and swiftly on a lathe with a threading dial, and metric threads can't. Here is a youtube video that explains it better than I can. https://www.youtube.com/watch?v=zG9XYDCDwWY https://www.youtube.com/watch?v=zG9XYDCDwWY If you ever see someone cutting threads on a lathe and they swiftly engage and disengage the power feed without stopping the lathe, they are cutting US threads on a US lathe. If they have to stop and reverse the lathe, they are using a metric lathe. This has an interesting implication on lathe design, metric lathes tend to be able to stop and reverse much faster than US lathes.