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National Stock Number:
5305-01-057-4279
Federal Supply Class:
5305
National Item Identification Number:
010574279
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:
| BACB30LP4-8 | 81205 | THE BOEING COMPANY | | BACB30LP4-8 | 92215 | HOWMET GLOBAL FASTENING SYSTEMS INC |
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Techincal Specification:
| COUNTERSINK ANGLE | 100.0 DEGREES NOMINAL | | FASTENER LENGTH | 0.910 INCHES MINIMUM AND 0.940 INCHES MAXIMUM | | GRIP DIAMETER | 0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM | | GRIP LENGTH | 0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM | | HEAD DIAMETER | 0.455 INCHES MINIMUM AND 0.510 INCHES MAXIMUM | | HEAD STYLE | FLAT COUNTERSUNK | | INTERNAL DRIVE STYLE | HIGH-TORQUE | | MATERIAL | IRON ALLOY 660 OVERALL | | NOMINAL THREAD DIAMETER | 0.250 INCHES | | SURFACE FINISH | 32.0 MICROINCHES BEARING SURFACE OF HEAD | | SURFACE FINISH | 32.0 MICROINCHES THREADS | | SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | QQ-P-416,TYPE 2,CLASS 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL | | SURFACE TREATMENT | CADMIUM AND CHROMATE OVERALL | | THREAD CLASS | 3A | | THREAD DIRECTION | RIGHT-HAND | | THREAD LENGTH | 0.400 INCHES MINIMUM AND 0.450 INCHES MAXIMUM | | THREAD QUANTITY PER INCH | 28 | | THREAD SERIES DESIGNATOR | UNJF |
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