Socket Shoulder bolts are fasteners that have an unthreaded portion of the shank that functions as a bearing surface or spacer.
These are measured by the Shoulder Only, for this size the shoulder diameter is M6, the length of the shoulder is 10mm and the thread on the end is M5.
It is important to note the threaded portion is NOT included in the length.
They have an in-hex drive and are fastened using a hexagonal wrench also known as an Allen key. Use Allen key size = 3.0mm
