What is a metric thread size and how does this affect screw dimensions?
Screws, bolts, nuts, and all other types of fasteners will comply with one of two dimension units (Imperial or Metric).
All of the thread sizes listed for our screws on this page are in Metric sizes or 'M'.
The identification of a metric thread size is defined through a set of standard types, for example 'M3' is standard metric thread size 3mm in overall diameter.
Thread sizes affect the dimensions of screws in multiple ways. The fundamental diameter of the thread and the pitch will change depending on selected size. Corresponding with thread size, the head diameter and height of the screw will also change.
There are multiple pitch types associated with metric fasteners but for the purposes of general use and the screws featured on our website, these all comply with standard metric coarse pitch.
Example dimensions are given below for a socket cap head screw/bolt:
|Metric Size (M)||Pitch (mm)||Thread Diameter (mm)||Head Diameter (mm)||Head Height (mm)||Hex Key size (mm)|