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Common Fastener Types

Nuts
Washers
Hex
Bolts
Wood
Screws
Sheet Metal
Screws
Machine
Screws
Socket
Screws
Lag
Bolts
Carriage
Bolts

Drive Types

Slotted
Phillips
Combo
Frearson
Pozidriv
Hex
Six-Lobe
Square

Head Styles

Hex Head
Pan Head
Flat Head
Round Head
Oval Head
Truss Head
Socket Head
Button Head
Low Carbon
Grade 5
Grade 8
Class 8.8
Class 10.9
Class 12.9

Grade (US) / Class (Metric) & Strength Markings

Imperial vs. Metric Reference Chart

Measuring Diameter & Length

Non-Countersunk
Countersunk
Non-Countersunk
Countersunk

Nuts & Washer Sizing

3/8" -16 Hex Bolt

3/8" Washer

3/8" -16 Nut

Washer and Nut sizes are based on the screw or bolt that they fit.

1/4" SAE

(narrower ring)

1/4" USS

(wider ring)

1/4" x 1" Fender

(larger ring)

Machine threaded fasteners specify a thread density in Threads Per Inch (US) or as a Thread Pitch in mm (Metric).

For a given diameter, a fastener may be available in coarse (standard), fine and sometimes super fine thread.

Thread Count & Thread Pitch

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