Well, the plan is to use forging to make them, but the ones on this rocket were cast as a blank and machined. One presumes that they are still working on the fo

Well, the plan is to use forging to make them, but the ones on this rocket were cast as a blank and machined. One presumes that they are still working on the forging system. https://twitter.com/elonmusk/status/878821062326198272 https://twitter.com/elonmusk/status/878821062326198272