[polygotdomain]

Having recently bought a metal lathe, and in general having a long time fascination with manufacturing, broaching is freaking mind blowing. Imparting form into metal by extremely strategic shaving off thousandths until you get to what you're looking for. It just doesn't seem like it should actually work at all, yet we wouldn't have things like allen bolts, splines, or keyways without them. Turns out all you need is the right geometry and super hard metal to make it work.

Rotary broaches are just so cool in that getting the right angle and wobble to the tooling is incredibly important, but it just seems like magic when it actually does it's thing. https://youtu.be/GWyHJVOxKK4?t=444 It's only when I saw what it was doing with the rotary motion stabilized that it started to make sense. https://youtu.be/4-3gPWl6wfU?t=95