Inside threads are found on the inside of nuts, the place a bolt (with an exterior thread) is screw into. When speaking about screws we are referring to External Thread. Broadly speaking Allow me to share two different types of Thread: A nut might be locked by a screw pin, https://deanrqpml.newsbloger.com/29903724/the-fact-about-types-of-screw-heads-chart-that-no-one-is-suggesting