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		                        | National Stock Number:
 5305-01-329-1469
 
 Federal Supply Class:
 5305
 
 National Item Identification Number:
 013291469
 
 Description:
 SCREW,MACHINE
 
 Detail:
 An externally threaded fastener whose threaded portion is of one nominal diameter, No 0 (0.060 in./1.5 mm) or larger, designed to be held or driven with either a wrench or an inserted driver or both (excluding internal socket or internal multiple spline types), in sizes below No. 10 (0.190 in./5 mm). No. 10 and larger sizes must have a head designed for any type inserted driver (excluding internal socket or internal multiple spline types), but may also be designed for external wrenching. A locking feature may be incorporated in the design of the head or threads. Excludes BOLT, CLEVIS; BOLT, EXTERNALLY RELIEVED BODY; SCREW, EXTERNALLY RELIEVED BODY; and SCREW, ASSEMBLED WASHER. See also, SCREW, INSTRUMENT; BOLT, MACHINE; BOLT, INTERNAL WRENCHING; and SCREW, CAP SOCKET HEAD.
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 Manufacturer Information:
 
 | 1/4-20UNC-3AX1 1/4IN.LG NICU ALY | 80204 | AMERICAN NATIONAL STANDARDS INSTITUTE INCORPORATED |  | FF-S-92 | 81348 | FEDERAL SPECIFICATIONS PROMULGATED BY GENERAL SERVICES ADMINISTRATION WASHINGTON DC | 
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 Techincal Specification:
 
 | COUNTERSINK ANGLE | 82.0 DEGREES NOMINAL |  | FASTENER LENGTH | 1.190 INCHES MINIMUM AND 1.250 INCHES MAXIMUM |  | HEAD DIAMETER | 0.452 INCHES MINIMUM AND 0.507 INCHES MAXIMUM |  | HEAD STYLE | FLAT COUNTERSUNK |  | INTERNAL DRIVE STYLE | SLOT |  | NOMINAL THREAD DIAMETER | 0.250 INCHES |  | SCREW MATERIAL | NICKEL ALLOY 400 |  | SCREW MATERIAL DOCUMENT AND CLASSIFICATION | QQ-N-281 CL A FED SPEC SINGLE MATERIAL RESPONSE |  | THREAD CLASS | 3A |  | THREAD DIRECTION | RIGHT-HAND |  | THREAD LENGTH | 0.937 INCHES MINIMUM AND 1.097 INCHES MAXIMUM |  | THREAD QUANTITY PER INCH | 20 |  | THREAD SERIES DESIGNATOR | UNIFIED NATIONAL COARSE (UNC) | 
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