Fastener Type Chart
This technical information has been supplied by boltdepot.com
Fastener Categories
Wood Screws
Screws with a smooth shank and tapered point for use in wood.
Abbreviated WS
Hex Bolts
Bolts with a hexagonal head with threads for use with a nut or tapped hole.
Abbreviated HHMB or HXBT
Machine Screws
Screws with threads for use with a nut or tapped hole.
Abbreviated MS
Carriage Bolts
Bolts with a smooth rounded head that has a small square section underneath.
Sheet Metal Screws
Fully threaded screws with a point for use in sheet metal.
Abbreviated SMS
Lag Bolts
Bolts with a wood thread
and pointed tip.
Abbreviated Lag
Self Drilling SMS
A Sheet metal screw with a self drilling point.
Set Screws
Bolts with a wood thread
and pointed tip.
Abbreviated Lag
Head Styles
Flat
A countersunk head with a flat top.
Abbreviated FH
Round
A domed head.
Abbreviated RH
Oval
A countersunk head with a rounded top.
Abbreviated OH or OV
Hex
A hexagonal Head.
Abbreviated HH or HX
Pan
A slightly rounded head with short vertical sides.
Abbreviated PN
Hex Washer
A hex head with built
in washer.
Truss
An extra wide head with a rounded top.
Abbreviated Truss
Slotted Hex Washer
A hex head with built in washer and a slot.
Drive Types
Phillips and Frearson
An X shaped drive.
Abbreviated PH
Slotted
A slot in the head.
Abbreviated SL
Combination
A combination of slotted and Phillips drives.
Abbreviated Combo
Socket or Allen
A hexagonal hole for use with and Allen wrench.
Nut Types
Hex
A six sided nut. Also referred to as a finished hex nut.
Wing
A nut with 'wings' for hand tightening.
Tee
A nut designed to be driven into wood to create a threaded hole.
Nylon Insert Lock
A nut with a nylon insert
to prevent backing off.
Also referred to as a Nylock
Cap or Acorn
A nut with a domed top over the end of the fastener.
Square
A four sided nut.
Jam
A hex nut with a reduced height.
Flange
A nut with a built in washer like flange.
Prevailing torque lock
A non-reversible nut used for high temperature applications
Nylon Insert Jam Lock
A nylock nut with a reduced height.
Kep
​A nut with a built in external tooth lock washer, used to speed up assembly.
Washer Types
Flat
A flat washer used to
distribute load. vailable in SAE, USS, and other patterns.
External Tooth Lock
A washer with external 'teeth' Used to prevent nuts and bolts from backing out.
Fender
An oversize flat washer used to further distribute load especially on soft materials.
Internal Tooth Lock
A washer with internal 'teeth' Used to prevent nuts and bolts from backing out.
Finishing
A washer used to obtain a 'finished' look. Usually used with oval head screws.
Square
A square shaped washer.
Split Lock
The most common style of washer used to prevent nuts and bolts from backing out.