9540-01-437-4998 BEAM,STRUCTURAL Index 6145-01-437-5000 CABLE,POWER,ELECTRICAL

National Stock Number:
5305-01-437-4999

Federal Supply Class:
5305

National Item Identification Number:
014374999

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.


Manufacturer Information:
S00464-4-7P88277THE BOEING COMPANY
SC2657-4-7P06950HOWMET GLOBAL FASTENING SYSTEMS INC


Techincal Specification:
THREAD SERIES DESIGNATORUNJF
NOMINAL THREAD DIAMETER0.250 INCHES
THREAD QUANTITY PER INCH28
THREAD CLASS3A
THREAD DIRECTIONRIGHT-HAND
THREAD LENGTH0.318 INCHES NOMINAL
FASTENER LENGTH0.730 INCHES MINIMUM AND
0.760 INCHES MAXIMUM
MATERIALIRON ALLOY 660 OVERALL
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 5731 ASSN STD SINGLE MATERIAL RESPONSE OR
AMS 5737 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
SURFACE TREATMENTCADMIUM AND
CHROMATE OVERALL
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416, TYPE 2, CLASS 2 FED SPEC ALL TREATMENT RESPONSES OVERALL
MINIMUM TENSILE STRENGTH160000 POUNDS PER SQUARE INCH
MINIMUM YIELD STRENGTH95000 POUNDS PER SQUARE INCH
HEAD STYLEHEXAGON
HEAD HEIGHT0.125 INCHES MINIMUM AND
0.140 INCHES MAXIMUM
WIDTH BETWEEN FLATS0.430 INCHES MINIMUM AND
0.439 INCHES MAXIMUM
INTERNAL DRIVE STYLETORQUE-SET RIBBED
GRIP LENGTH0.240 INCHES MINIMUM AND
0.260 INCHES MAXIMUM
GRIP DIAMETER0.2485 INCHES MINIMUM AND
0.2495 INCHES MAXIMUM
SURFACE FINISH32.0 MICROINCHES GRIP
32.0 MICROINCHES THREADS
SPECIAL FEATURESGRIP CHAMFER AT THREADS 35.0 DEGREES


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