What are the three principal parts of a bolt?

The three principal parts of a bolt are indeed the head, thread, and grip. The head is the larger end of the bolt, designed to be struck or turned, allowing for installation and removal. The threads are the helical ridges that run along a portion of the bolt's shaft, facilitating engagement with a nut or a tapped hole to secure objects together. The grip refers to the unthreaded portion of the bolt that provides a bearing surface when the bolt is installed; it acts as a support for the components being fastened.

This combination of these parts ensures that bolts can effectively hold structures or machinery together under various loads and stresses, which is vital in mechanical and structural applications. Understanding these components is essential for safe and effective use in mechanical assemblies.