Common Fastener Related Abbreviations

Abbreviation Meaning
&NT With Nut
AN Precedes a dimensional specification for aircraft fasteners developed by the Aeronautical Standards Group.
ASTM American Society for Testing and Materials. Used preceding a standard number developed by that group.
BR Brass
BSF British Standard Fine
BSW British Standard Whitworth
BT Bolt (on drawings)
C National Coarse Thread
CL Class (Metric Material/Strength Specification)
CR Chrome
CSS Counter Sunk Screw (flat or oval head)
CT coarse Thread
DIN An abbreviation for Deutsches Institut für Normung, the German standards body. In reference to fasteners DIN indicates fasteners that conform to a specific metric standard (will be followed by the standard number).
F Fully Threaded
FH Flat Head
FIL Fillister Head
FIN Finishing (Washer)
FNDR Fender (Washer)
FT Fine Thread, Fully Threaded
G Grade
Galv. Galvanized
Galvi Galvanized
GR Grade
GV Galvanized
HD Head
HHMB Hex Head Machine Bolt
HVHX Heavy Pattern Hex Bolt
HX Hex
JMNT Jam Nut
LB Lag Bolt, weight in pounds
LH Left Hand Thread
LW Lock Washer
M Metric
MB Machine Bolt
MS Machine Screw
MSNT Machine Screw Nut
NC National Coarse Thread
NF National Fine Thread
NT Nut
OH Oval Head
OV Oval Head
P Phillips
PH Phillips Head
Phil. Phillips Drive
PN Pan Head
PT Partial Thread
RD Round Head
RH Round Head, or Right Hand Thread
S Slotted
S/S Stainless Steel
SAE SAE Pattern (Washers) These washers have a smaller outside diameter than USS pattern washers, Also used to indicate US Fine Thread
SBR Silicon Bronze
SD Square Drive
SEMS A type of pre-made screw and washer assembly
SKT Socket
SL Slotted
Slot. Slotted Drive
SMS Sheet Metal Screw
SQ Square
SS Stainless Steel, Set Screw
USS USS Pattern (washers). These washers have a larger outside diameter than SAE pattern washers, Also used to indicate US coarse Thread
WS Wood Screw
Z Zinc