5305-01-266-7800, SCREW,CLOSE TOLERANCE

National Stock Number:
5305-01-266-7800

Federal Supply Class:
5305

National Item Identification Number:
012667800

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:

NAS1581A5R8

80205

NATIONAL AEROSPACE STANDARDS COMMITTEE AEROSPACE INDUSTRIES ASSOCIATION OF AMERICA INC NOT FOR RFQ OR SOLICITATION USE

Techincal Specification:

THREAD SERIES DESIGNATOR	UNJF
NOMINAL THREAD DIAMETER	0.312 INCHES
THREAD QUANTITY PER INCH	24
THREAD CLASS	3A
THREAD DIRECTION	RIGHT-HAND
THREAD LENGTH	0.476 INCHES MINIMUM AND
	0.526 INCHES MAXIMUM
FASTENER LENGTH	0.986 INCHES MINIMUM AND
	1.016 INCHES MAXIMUM
MATERIAL	STEEL COMP 4140 OR
	STEEL COMP E4340 OR
	STEEL COMP 8740 OVERALL
MATERIAL DOCUMENT AND CLASSIFICATION	MIL-S-5626 MIL SPEC 1ST MATERIAL RESPONSE OR
	MIL-S-5000 MIL SPEC 2ND MATERIAL RESPONSE OR
	MIL-S-6049 MIL SPEC 3RD MATERIAL RESPONSE OVERALL
SURFACE TREATMENT	CADMIUM AND
	CHROMATE OVERALL
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION	QQ-P-416,TYPE 2,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
HARDNESS RATING	36.0 ROCKWELL C MINIMUM AND
	40.0 ROCKWELL C MAXIMUM OVERALL
MINIMUM TENSILE STRENGTH	160000 POUNDS PER SQUARE INCH
HEAD STYLE	FLAT COUNTERSUNK
HEAD DIAMETER	0.429 INCHES MINIMUM AND
	0.479 INCHES MAXIMUM
COUNTERSINK ANGLE	99.0 DEGREES MINIMUM AND
	101.0 DEGREES MAXIMUM
INTERNAL DRIVE STYLE	TORQUE-SET RIBBED
GRIP LENGTH	0.490 INCHES MINIMUM AND
	0.500 INCHES MAXIMUM
GRIP DIAMETER	0.3110 INCHES MINIMUM AND
	0.3120 INCHES MAXIMUM
SURFACE FINISH	63.0 MICROINCHES BEARING SURFACE OF HEAD
	32.0 MICROINCHES GRIP
	32.0 MICROINCHES THREADS
SPECIFICATION/STANDARD DATA	80205-NAS1581 PROFESSIONAL/INDUSTRIAL ASSOCIATION STANDARD
PART NAME ASSIGNED BY CONTROLLING AGENCY	NAVY SPECIAL PROJECT

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