The trapezoidal thread is analogous towards the acme thread, apart from that the thread angle is 300. It can be created in metric dimensions; that is certainly why it is actually known as "metric lead screw" or "metric acme screw." A devoted type of micrometer, identified as a thread mic https://types-of-decking74950.newsbloger.com/29928359/types-of-screw-head-drives-for-dummies