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91257A634 — SCREW,CAP,HEXAGON HEAD

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

91257A634: SCREW,CAP,HEXAGON HEAD.

The SCREW,CAP,HEXAGON HEAD is a the manufacturer industrial component. Key specifications include head_style: HEXAGON, head_height: 0.234 INCHES NOMINAL IN, thread_length: 1.000 INCHES MINIMUM AND 1.312 INCHES MAXIMUM IN, fastener_length: 2.500 INCHES NOMINAL IN, hardness_rating: 33.0 ROCKWELL C MINIMUM AND 39.0 ROCKWELL C MAXIMUM OVERALL, special_features: HIGH-STRENGHT ALLOY STEEL; CLASS 2A THREAD FIT; GRADE 8; ZINC YELLOW-CHROMATE PLATED A. This part is cataloged in the U.S.

Government catalog under NSN 5305-01-533-2971, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
91257A634
NSN: 5305-01-533-2971
FSC: 5305 — Screws
CAGE: 39428 — MCMASTER-CARR SUPPLY CO (USA)
SPECIFICATIONS
head_styleHEXAGON
head_height0.234 INCHES NOMINAL IN
thread_length1.000 INCHES MINIMUM AND 1.312 INCHES MAXIMUM IN
fastener_length2.500 INCHES NOMINAL IN
hardness_rating33.0 ROCKWELL C MINIMUM AND 39.0 ROCKWELL C MAXIMUM OVERALL
special_featuresHIGH-STRENGHT ALLOY STEEL; CLASS 2A THREAD FIT; GRADE 8; ZINC YELLOW-CHROMATE PLATED A
thread_directionRIGHT-HAND
width_between_flats0.563 INCHES NOMINAL IN
end_item_identificationASSULT HOSELINE SYSTEM NSN 3835-01-511-7335
minimum_tensile_strength150000 POUNDS PER SQUARE INCH LBS
material_document_and_classificationSAE J429 ASSN STD ALL MATERIAL RESPONSES OVERALL
part_name_assigned_by_controlling_agencyBOLT
NSN5305-01-533-2971
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 91257A634 · OEM ⚠ VERIFY BEFORE ORDERING Verify thread pitch before ordering — metric (M8×1.25) ≠ imperial (5/16-18). Wrong thread = wrong part. Grade/class stamped on bolt head determines tensile strength ✓ BROKER TIP Grade/class stamped on head determines tensile strength. Grade 8 > Grade 5 > Grade 2. Always confirm head marking matches specification requirement PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
HEAD HEIGHT: 0.234 INCHES NOMINAL IN
•
FASTENER LENGTH: 2.500 INCHES NOMINAL IN
•
THREAD LENGTH: 1.000 INCHES MINIMUM AND 1.312 INCHES MAXIMUM IN
•
HARDNESS RATING: 33.0 ROCKWELL C MINIMUM AND 39.0 ROCKWELL C MAXIMUM OVERALL
•
MATERIAL DOCUMENT AND CLASSIFICATION: SAE J429 ASSN STD ALL MATERIAL RESPONSES OVERALL
•
HEAD STYLE: HEXAGON
•
THREAD DIRECTION: RIGHT-HAND
•
WIDTH BETWEEN FLATS: 0.563 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
HEAD HEIGHT0.234 INCHES NOMINAL IN
FASTENER LENGTH2.500 INCHES NOMINAL IN
THREAD LENGTH1.000 INCHES MINIMUM AND 1.312 INCHES MAXIMUM IN
HARDNESS RATING33.0 ROCKWELL C MINIMUM AND 39.0 ROCKWELL C MAXIMUM OVERALL
MATERIAL DOCUMENT AND CLASSIFICATIONSAE J429 ASSN STD ALL MATERIAL RESPONSES OVERALL
HEAD STYLEHEXAGON
THREAD DIRECTIONRIGHT-HAND
WIDTH BETWEEN FLATS0.563 INCHES NOMINAL IN
SPECIAL FEATURESHIGH-STRENGHT ALLOY STEEL; CLASS 2A THREAD FIT; GRADE 8; ZINC YELLOW-CHROMATE PLATED A
MINIMUM TENSILE STRENGTH150000 POUNDS PER SQUARE INCH LBS
OTHER ITEMS IN FSC 5305 — Screws
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5305-00-001-5016 5305-00-001-9160 5305-00-001-9629 5305-00-001-9742 5305-00-001-9768 5305-00-003-4306 5305-00-003-6694 5305-00-003-6753
SUBSTITUTES & CROSS-REFERENCES 1
13019965Reference document
Same NSN cross-reference
Reference document — Vendor item drawing reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 91257A634?
91257A634 is a SCREW,CAP,HEXAGON HEAD.
What parts can replace 91257A634?
There is 1 known substitute for 91257A634: 13019965. Substitute compatibility should be verified for your specific system.
What is the NSN for 91257A634?
91257A634 is cataloged in the U.S. Government catalog under NSN 5305-01-533-2971. This indicates validated use in U.S. government and defense supply chains.
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✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.