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National Stock Number:
5305-01-322-1597
Federal Supply Class:
5305
National Item Identification Number:
013221597
Description:
SCREW,CLOSE TOLERANCE
Detail:
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.
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Manufacturer Information:
| ST3M559-4-8 | 76301 | THE BOEING COMPANY |
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Techincal Specification:
| THREAD SERIES DESIGNATOR | UNJF | | NOMINAL THREAD DIAMETER | 0.250 INCHES | | THREAD QUANTITY PER INCH | 28 | | THREAD CLASS | 3A | | THREAD DIRECTION | RIGHT-HAND | | THREAD LENGTH | 0.397 INCHES NOMINAL | | FASTENER LENGTH | 0.881 INCHES MINIMUM AND | | 0.928 INCHES MAXIMUM | | MATERIAL | STEEL OVERALL | | SURFACE TREATMENT | CADMIUM OVERALL | | HEAD STYLE | FLAT COUNTERSUNK UNDERCUT | | HEAD DIAMETER | 0.497 INCHES MINIMUM AND | | 0.507 INCHES MAXIMUM | | HEAD HEIGHT | 0.106 INCHES NOMINAL | | COUNTERSINK ANGLE | 99.0 DEGREES MINIMUM AND | | 101.0 DEGREES MAXIMUM | | INTERNAL DRIVE STYLE | RECESSED TYPE I | | GRIP LENGTH | 0.490 INCHES MINIMUM AND | | 0.510 INCHES MAXIMUM | | GRIP DIAMETER | 0.2641 INCHES MINIMUM AND | | 0.2651 INCHES MAXIMUM | | SPECIFICATION/STANDARD DATA | 76301-ST3M559-4-8 PROFESSIONAL/INDUSTRIAL ASSOCIATION SPECIFICATION |
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