Collar bolts are specialized fasteners featuring a cylindrical, unthreaded collar between the bolt head and the threaded shank. The collar provides extra shear strength and helps with precise alignment during installation. These bolts are commonly used in high-strength applications such as automotive assemblies, heavy machinery, and structural joints where controlled clamping force and resistance to vibration are important. Collar bolts are often paired with locknuts or washers to enhance stability and load distribution.