Screws

Compared with other fastening systems, nuts and screws has the advantage that they can be disassembled as needed, while other fasteners such as rivets are designed for permanent installation. Screws are often used with nuts and washers, where the washer provides an increase in surface area over which the attachment force is applied. There are a variety of different types of nuts that can be used with a screw, the most common one being hex nuts. Other nut types include:

• Prevailing Torque Locknuts
• Nylon Insert Locknuts
• K-Lock Locknuts
• Slotted Hex (Castle) Nuts
• Flange Nuts
• Cap Nuts
• Coupling Nuts
• Wing Nuts)
• Square Nuts
• Panel Nuts
• Surface Mount Nuts
• Rivet Nuts

AN Screws

AN - an acronym for “Army and Navy” and sometimes "Air Force and Navy", AN screws are characterized by their specification and quality control. AN Screws are industrial aircraft screws and are manufactured according to Air Force-Navy specs. They are manufactured from cadmium or zinc plated corrosion resistant steel, unplated corrosion-resistant steel, and anodized aluminum alloys. Length, grip, diameter, drilled head, and shank are the different variables within an AN screw part number. They can be used for both ductile and/or shear applications and are coded to a specific standard. To the untrained eye, AN screws look like ordinary screws. They feature a partially threaded shank with a head. Like with most other screws, they are designed to secure multiple parts together. AN screws can be inserted through the threaded holes of two or more parts, after which they will hold the parts together. AN screws are distinguished from ordinary screws by their specification and rigorous quality control. The AN specification is the predecessor to the Military Specifications (MS or Mil-Spec) which is currently used by the US military. Current AN screws are used extensively in aerospace and aviation for their measurable reliability. AN Screws are also used in many fastening applications where their form, function and reliability are desired. AN Screws are typically only used in applications where the additional cost of the specification, quality and reliability is justified.

NAS Screws

NAS screws comply with the National Aerospace Standard and are commonly used for high technology systems. NAS screws are necessary for high strength applications and consist of a fine-threaded, dimple headed hex screw. Material markings for NAS screws are the same as AN screws, except they may be either raised or recessed.

NASM Screws

NASM screws include precision fasteners that previously fell under MIL-spec requirements and were converted to NASM specifications by the Aerospace Industries Association. The “MS” portion of the part number indicates the specification it meets (ex.MS16997).

MS Screws

MS screws have been tested and certified to Military Standard for use in high-performance applications. Military Standard screws are available with either coarse or fine threads and are made from a range of materials with different finishes.

MS16997 Socket Cap Screws

Socket head cap screws with a UNC Coarse Thread

NA Screws

NA Screws are the most recent standard covering the requirements for metric aerospace fasteners.

What is Federal Supply Class 5305?

FSC 5305 is the Federal Supply Class(formally known as NATO Supply Classification Class NSC 5305) in the USA for supply items codified in the category of Screws.

What is NATO Supply Classification Class 5305?

NSC 5305 is the NATO Supply Classification Class (also known as Federal Supply Class FSC 5305 in the USA) for supply items codified in the category of Screws.

Which Federal Supply Group is FSC 5305 in?

FSC 5305 is in Federal Supply Group(FSG) 53 which contains .

Which NATO Supply Classification Group is NSC 5305 in?

NSC 5305 is in NATO Supply Classification Group(NSG) 53 which contains .

What is an Externally Relieved Body Screw? 15966 Items

An Externally Relieved Body Screw (SCREW,EXTERNALLY RELIEVED BODY) is an externally threaded fastener whose threaded portion is of one nominal diameter, and whose unthreaded portion has been machined or ground in one or more places or over its entire length to a maximum diameter less than the minimum pitch diameter of the thread (excludes undercut for thread relief). It is No. 0 (0.060 IN.) (1.5 mm) or larger, and is designed to be held or driven with either a wrench or inserted driver (excluding internal socket and multiple spline types) or both in sizes below No. 10 (0.190 IN.) (5 mm) and larger sizes must have a head designed for any type inserted driver (excluding internal socket and multiple spline types) but may also be designed for external wrenching. A locking feature may be incorporated in the design of the head or threads. See also BOLT, EXTERNALLY RELIEVED BODY and BOLT, INTERNAL WRENCHING.

What is a Wood Screw? 10037 Items

A Wood Screw (SCREW,WOOD) is an unhardened externally threaded fastener whose continuous thread extends from a gimlet point for a distance of approximately two-thirds of the length of the screw and which is designed to be driven with an inserted driver.

What is an Instrument Screw? 924 Items

An Instrument Screw (SCREW,INSTRUMENT) is an externally threaded fastener similar to a SCREW, MACHINE but smaller than No. 0 (0.060 IN.) (1.5 mm) in size.

What is a Machine Screw? 159937 Items

A Machine Screw (SCREW,MACHINE) is an externally threaded fastener whose threaded portion is of one nominal diameter, No 0 (0.060 in./1.5 mm) or larger, designed to be held or driven with either a wrench or an inserted driver or both (excluding internal socket or internal multiple spline types), in sizes below No. 10 (0.190 in./5 mm). No. 10 and larger sizes must have a head designed for any type inserted driver (excluding internal socket or internal multiple spline types), but may also be designed for external wrenching. A locking feature may be incorporated in the design of the head or threads. Excludes BOLT, CLEVIS; BOLT, EXTERNALLY RELIEVED BODY; SCREW, EXTERNALLY RELIEVED BODY; and SCREW, ASSEMBLED WASHER. See also, SCREW, INSTRUMENT; BOLT, MACHINE; BOLT, INTERNAL WRENCHING; and SCREW, CAP SOCKET HEAD.

What is an Assembled Washer Screw? 3900 Items

An Assembled Washer Screw (SCREW,ASSEMBLED WASHER) is a SCREW, (as modified) to which has been assembled one or more nonremovable washer(s).

What is a Setscrew? 44381 Items

A Setscrew is an externally threaded device whose threaded portion is of one nominal diameter with or without a head and having a cup, cone, or other type of machined point designed to prevent or restrict relative movement of parts and designed to be driven with either a wrench or inserted driver. A locking feature may be incorporated in the design of the head or threads.

What is a Thumbscrew? 7655 Items

A Thumbscrew is an externally threaded fastener whose threaded portion is of one nominal diameter. It may have an unthreaded portion with a diameter less than, equal to, or greater than the diameter of the threaded portion. It has either a vertically flattened, circular knurled, or wing type head, all of which are designed for rotation by the thumb and fingers. For items having wrenching facilities such as socket recess, multiple spline or slot heads, use SCREW (as modified) or BOLT (as modified).

What is an Eye Screw? 343 Items

An Eye Screw (SCREW,EYE) is a fastening device with one end formed in the shape of an eye and the other end threaded with a lag or wood screw type of thread.

What is a Drive Screw? 1477 Items

A Drive Screw (SCREW,DRIVE) is a hardened cylindrical fastener with multiple spiral flutes on its shank. It also has an end smaller in diameter than the outside diameter of the spiral flutes, which acts as a pilot when driven into a drilled hole.

What is a Screw Assortment? 763 Items

A Screw Assortment is two or more different sizes and/or types of screws grouped together in a single package.

What is a Socket Head Cap Screw? 87764 Items

A Socket Head Cap Screw (SCREW,CAP,SOCKET HEAD) is an externally threaded fastener whose threaded portion is of one nominal diameter. The head has an internal socket or multiple spline for use with an inserted driver. A locking feature may be incorporated in the design of the head or threads. Excludes items with bevel (conical) heads. See BOLT, INTERNAL WRENCHING. Excludes SCREW, SHOULDER; and SCREW, MACHINE.

What is a Machine Screw And Nut And Washer Assortment? 746 Items

A Machine Screw And Nut And Washer Assortment is an assortment of two or more of the same or different types of machine screws, machine screw nuts, washers and the like.

What is a Screw And Nail Assortment? 37 Items

A Screw And Nail Assortment is an assortment of nails and screws of various types and/or sizes.

What is a Hexagon Head Cap Screw? 74002 Items

A Hexagon Head Cap Screw (SCREW,CAP,HEXAGON HEAD) is an externally threaded fastener designed for insertion into holes in assembled parts, for mating with a preformed internal thread and for tightening or releasing by torquing the head. The threaded and unthreaded portions are both of the same nominal diameter of 0.190 inch (5 mm) or larger. Head dimensions and sizes of threaded and unthreaded portions shall conform to internationally recognized fastener standards. The thread length being the controlled dimension, the grip length is not specified. A locking feature may be incorporated in the design of the head or threads. The head is not designed to be held or driven with an inserted driver or by the thumb and fingers. Excludes BOLT,MACHINE; BOLT,EXTERNALLY RELIEVED BODY; BOLT,INTERNAL WRENCHING; and SCREW,CAP,SOCKET HEAD.

What is a Panel Fastener Screw? 702 Items

A Panel Fastener Screw (SCREW,PANEL FASTENER) is a headed, threaded fastening device with special square threads, which is designed to be attached to a panel by means of a retaining washer. The screw fastener is used in conjunction with a speed nut to facilitate fastening two items.

What is a Shoulder Screw? 16082 Items

A Shoulder Screw (SCREW,SHOULDER) is an externally threaded fastener whose threaded portion is of one nominal diameter, No 0 (0.060 IN.) (1.5 mm) or larger. It has a round unthreaded neck or shank all or part of which is of greater diameter than the threaded portion. The head is designed to be driven with either a wrench or an inserted driver or both in sizes below No. 10 (0.190 IN.) (5 mm) nominal diameter. No. 10 (0.190 IN.) (5 mm) and larger sizes must be designed for any type of inserted driver, but may also provide for external wrenching of the head. A locking feature may be incorporated in the design of the head or threads. For items which are both shouldered and have an externally relieved body, use SCREW, EXTERNALLY RELIEVED BODY. For items with a No. 10 (0.190 IN.) (5 mm) or larger thread diameter without an inserted driver head, use BOLT, SHOULDER. Excludes BOLT, INTERNAL WRENCHING and SCREW, CAP, SOCKET HEAD.

What is a Close Tolerance Screw? 20396 Items

A Close Tolerance Screw (SCREW,CLOSE TOLERANCE) is a SCREW, MACHINE or SCREW, CAP, SOCKET HEAD whose unthreaded portion is of specified grip length, plated or unplated, and is machined to a tolerance of one thousandth (0.001 IN.) (0.025 mm) or less of a specific diameter for items (1.000 IN.) (25 mm) or less in diameter. Items over (1.000 IN.) (25 mm) in diameter shall have a tolerance of fifteen ten thousandths (0.0015 IN.) (0.038 mm) or less. The nominal major diameter of the threads shall be at least one thousandth (0.001 IN.) (0.025 mm) below the minimum shank diameter, but not below the minimum major diameter for applicable class of fit, as shown in the Screw Thread Standards, FED STD H28 and/or other nationally recognized standards. The head is designed to be held or driven with an inserted driver. It is not designed for rotation by the thumb and fingers. A locking feature may be incorporated in the design of the head or threads.

What is a Panel Screw Assembly? 3560 Items

A Panel Screw Assembly (SCREW ASSEMBLY,PANEL) is a headed, threaded fastening device over which may be assembled; (1) a stand-off; (2) a flanged bushing with washer(s) and/or a shouldered bushing without a flange, or it may have an internally threaded sleeve that is an integral part of the screw; a washer and an externally thread self-locking bushing that is driven by an inserted driver. Attached to panel by threaded bushing or by flaring end of stand-off, or bushing. Used in conjunction with a speed nut, nut plate, or driven into a threaded hole in the item that the panel is fastened to. May be spring loaded.

What is a Lag Screw? 741 Items

A Lag Screw (SCREW,LAG) is an externally threaded fastener having a square or hexagon head and with a continuous thread (wood screw type or fetter type) extending from a gimlet or cone point for a distance of slightly more than one-half the length of the screw.

What is a Self-Drilling Screw? 524 Items

A Self-Drilling Screw (SCREW,SELF-DRILLING) is a hardened, externally-threaded fastener with a self-drilling point. It drills, taps and fastens and may have a machine screw thread or a nonmachine screw thread. The threads usually extend from behind the pilot to the bearing surface of the head.

Screw,Lock Plate 112 Items

What is a Tapping Screw? 11160 Items

A Tapping Screw (SCREW,TAPPING) is a hardened externally threaded fastener whose thread extends to the bearing surface of the head. The thread may be fluted or otherwise designed to cut or form its own mating thread. Excludes SCREW, ASSEMBLED WASHER.