HOW FASTENERS ARE IDENTIFIED
HOW FASTENERS ARE IDENTIFIED
GENERAL
Fasteners are identified by four or five attributes; Type, Material, Diameter, Length, and Thread Pitch or Count (machine thread fasteners only). This page describes what these attributes represent. Information on how they are written can be found on our How Fastener Measurements Are Notated page. Also for information on fastener abbreviations please see our Common Fastener Abbreviations page.
NOTE: With some fasteners, the terms bolt and screw are frequently used interchangeably.
TYPE
Fastener type can be divided into information on the Category or kind of fastener, Drive Type, and Head Style.
CATEGORY
Fasteners are divided into categories based on their function or design. For help identifying different fastener categories see our Fastener Type Chart.
EX: Wood Screw, Sheet Metal Screw, Hex Bolt, Lag Bolt, etc.
DRIVE TYPE
Fasteners in some categories are available with different drive types such as Philips or Slotted. In other categories such as lag bolts there is either only one drive type or the drive type is implied to be of a standard type. For help identifying different fastener drive types see our Fastener Type Chart.
EX: Philips, Slotted, Allen (a.k.a. Socket), Frearson (similar to Philips), etc.
