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National Stock Number:
5305-00-292-5490
Federal Supply Class:
5305
National Item Identification Number:
002925490
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:
| 3M54-4-21 | 76301 | THE BOEING COMPANY | | 54268-4-21 | 50394 | SPS TECHNOLOGIES INC UNBRAKO DIV | | HT42UA21 | 73197 | HI-SHEAR CORPORATION | | HT410A4-21 | 92215 | HOWMET GLOBAL FASTENING SYSTEMS INC | | HT42UA21 | L4528 | LISI AEROSPACE CANADA CORP DIV HI SHEAR HOLDINGS INC |
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Techincal Specification:
| THREAD SERIES DESIGNATOR | UNF | | NOMINAL THREAD DIAMETER | 0.250 INCHES | | THREAD QUANTITY PER INCH | 28 | | THREAD CLASS | 3A | | THREAD DIRECTION | RIGHT-HAND | | THREAD LENGTH | 0.443 INCHES MINIMUM AND | | 0.510 INCHES MAXIMUM | | FASTENER LENGTH | 1.765 INCHES MINIMUM AND | | 1.812 INCHES MAXIMUM | | MATERIAL | STEEL OVERALL | | SURFACE TREATMENT | CADMIUM OVERALL | | HEAD STYLE | FLAT COUNTERSUNK | | HEAD DIAMETER | 0.501 INCHES MINIMUM AND | | 0.506 INCHES MAXIMUM | | HEAD HEIGHT | 0.058 INCHES MINIMUM AND | | 0.060 INCHES MAXIMUM | | COUNTERSINK ANGLE | 100.0 DEGREES NOMINAL | | INTERNAL DRIVE STYLE | HIGH-TORQUE | | GRIP LENGTH | 1.302 INCHES MINIMUM AND | | 1.322 INCHES MAXIMUM | | GRIP DIAMETER | 0.2797 INCHES MINIMUM AND | | 0.2807 INCHES MAXIMUM | | SPECIAL FEATURES | FURNISHED WITH O RING |
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