Fasteners Guide made easy – a simple guide to Fasteners

Fasteners Guide made easy – a simple guide to Fasteners

Want to understand the naming convention behind Fasteners?
Its pretty easy once broken down.

Fasteners Guide

Example 1:

M12 X 70 COACH SCR A2-304 ST.ST

At first glance, this looks a little intimidating. Lets break it down.

  • M12 is the Width, an M12 would be thicker than an m10
  • 70 is the length.
  • Coach SCR is type of fixing / fastener (this is a coach screw)
  • A2 304 is the grade of material, these come in A2 and A4. A4 is commonly used by military personal whilst A2 is more commonly used in everyday jobs.
  • ST.ST stands for Stainless Steel.


Here is another Example going into more detail:

Machine screw Phillips pan Stainless steel 18-8 1/4 – 20 x 2″

  • Drive Type (this describes the type of tool used to install the fastener such as a phillips or a slotted) Its worth noting that some, such as carriage bolts do not have a drive therefore no drive type is specified.
  • Head Style ( the Head style is the shape of the head, this could be for example a hex or a flat)
  • Material e.g. steel or zinc
  • Length (this is measured from where the surface of the material will be when the fastener is installed, to the end.)


  • Size – For most fasteners, the size consists of two or three parts.
    Example: 1/2″ – 20 x 3″

    Diameter (this is measured on the outside of the threads. For US fasteners this is measured in inches (except for small diameters, where diameters are numbered), and for metric fasteners it is measured in millimetres (abbreviated mm or prefixed by M).
  • count Length
  • Thread Count/Pitch
  • Only machine threaded fasteners (nuts, and bolts that could take a nut) will have a thread count or thread pitch.


I hope that you found this Fasteners Guide useful.
Now that you understand how Fasteners work, feel free to take a browse through our store.

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