Fastener Abbreviations Glossary – Common Screw, Bolt & Nut Terms | Monster Bolts

Common Fastener Abbreviations

Fasteners often include a variety of abbreviations in their product descriptions and specifications. This guide breaks down the most common abbreviations used across screws, bolts, nuts, and washers. Whether you're shopping for stainless steel, trying to understand strength grades, or just deciphering a product label, this glossary is your go-to source.

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Material Abbreviations

Abbreviation Meaning
18-8 Stainless Steel with 18% Chromium and 8% Nickel – also referred to as 304 or A2.
A2 General-purpose stainless steel (304) used for most non-marine applications.
A4 Marine Grade Stainless Steel (316), ideal for high-corrosion environments.
AS Alloy Steel
Ti Titanium – Lightweight and extremely corrosion-resistant.

Specification Codes (ASTM, DIN, ISO)

Abbreviation Meaning
ASTM American Society for Testing and Materials
ASME American Society of Mechanical Engineers
DIN Deutsches Institut für Normung – Metric fastener standard (Germany)
ISO International Organization for Standardization
RoHS Restriction of Hazardous Substances – Environmental compliance standard
A194 Specifications for Carbon, Alloy and Stainless Steel nuts
A307 Relates to carbon, alloy and stainless steel nuts for bolts
A325 Relates to Heavy Hex Structural Bolt, similar to Grade 5
A490 Relates to alloy steel Heavy Hex Structural Bolt, similar to Grade 8
A449 Relates to Steel Hex Cap screws, bolts and studs
A563 Specification for Carbon and Alloy steel nuts
A574 Specifications for Alloy Steel Socket Head Cap screws
F436 Specifications for US and Metric Hardened Steel Washers
F594 Specifications for Stainless Steel Nuts
F835 Specifications for Alloy Steel Button Head and Flat Countersunk Socket Cap screws
F836M Specifications for Metric 'Style 1' stainless steel nuts
F837 Specifications for Stainless Steel Socket Head Cap Screws
F912 Specifications for Alloy Steel Socket Set Screws
DIN 84 Slotted Cheese Head Machine Screw
DIN 85 Slotted Pan Head Machine Screw
DIN 94 Cotter Pin
DIN 125A Flat Washer (without Chamfer)
DIN 125B Flat Washer (with Chamfer)
DIN 127B Split Lock Washer
DIN 137B Spring Wave Washer
DIN 315 Wing Nut
DIN 439B Finished Hex Jam Nut
DIN 911 Long Arm Hex Key
DIN 912 Hex Socket Head Cap Screw
DIN 916 Hex Socket Set Screw
DIN 931 Hex Head Cap Screw Partially Threaded
DIN 933 Hex Head Cap Screw Fully Threaded
DIN 934 Finished Hex Nut
DIN 939 Double End Stud
DIN 960 Hex Head Cap Screw Partially Threaded
DIN 961 Hex Head Cap Screw Fully Threaded
DIN 963 Slotted Flat Head Machine Screw
DIN 964 Slotted Oval Head Machine Screw
DIN 965 Phillips Flat Head Machine Screw
DIN 966 Phillips Oval Head Machine Screw
DIN 975 Threaded Rod
DIN 980V Hex Steel Prevailing Torque Lock Nut
DIN 985 Hex Nylon Insert Lock Nut
DIN 6334 Rod Coupling Nut
DIN 6797A External Tooth Lock Washer
DIN 6797J Internal Tooth Lock Washer
DIN 6912 Hex Low Socket Head Cap Screw
DIN 6921 Hex Flange Head Screw
DIN 6923 Hex Flange Nut
DIN 7985 Phillips Pan Head Machine Screw
DIN 7991 Hex Flat Socket Head Cap Screw
ISO 7379 Hex Socket Head Shoulder Screw
ISO 7380 Hex Button Socket Head Cap Screw

Finish & Coating Abbreviations

Abbreviation Meaning
BLK OX Black Oxide – Mild corrosion resistance and matte black appearance
ZN / Zn Zinc Plated – Economical corrosion-resistant coating
CR Chrome – Shiny, decorative, and corrosion-resistant
Galv. Galvanized – Coated in zinc for heavy-duty corrosion resistance

Fastener Type Abbreviations

Abbreviation Meaning
SHCS Socket Head Cap Screw
BHCS Button Head Cap Screw
FHCS Flat Head Cap Screw
SMS Sheet Metal Screw
SSS Socket Set Screw

Drive & Head Styles

Abbreviation Meaning
PH / P Phillips Drive
SQ Square Drive (Robertson)
HX / SKT Hex Drive / Socket
FH Flat Head (Countersunk)
PN Pan Head
OH Oval Head

For even more technical resources including how to measure fasteners, conversion charts, strength data, and more, visit our full Fastener Information Page.

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