Common Fastener 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 Course Thread |
| CL | Class (Metric/Material/Strength Specification) |
| CR | Chrome |
| CSS | Counter Sunk Screw (flat or oval head) |
| CT | Course Thread |
| DIN | An abbreviation for Deutsches Institut fur Normung, the German standards body. In reference to fasteners DIN indicates fasteners that conform to a specific metric standard (will be followed by a 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 Course Thread |
| NF | National Fine Thread |
| NT | Nut |
| OH | Oval Head |
| OV | Oval Head |
| P | Philips |
| PH | Philips Head |
| Phil. | Philips 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 Patter (washer). These washers have a smaller outside diameter than USS pattern washers. |
| 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. |
| WS | Wood Screw |
| Z | Zinc |