PartsTable
Technical Data Sheet
Download PDF

BLT1957 — BOLT,EXTERNALLY RELIEVED BODY

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

BLT1957: BOLT,EXTERNALLY RELIEVED BODY.

The BOLT,EXTERNALLY RELIEVED BODY is a the manufacturer industrial component. Key specifications include material: IRON ALLOY 660 OVERALL, head_style: DOUBLE HEXAGON EXTENDED WASHER, head_height: 0.320 INCHES MINIMUM AND 0.340 INCHES MAXIMUM IN, thread_class: 1A A, thread_length: 0.502 INCHES MINIMUM AND 0.522 INCHES MAXIMUM IN, fastener_length: 1.052 INCHES MINIMUM AND 1.072 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5306-00-879-3339, 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
BLT1957
NSN: 5306-00-879-3339
FSC: 5306 — Bolts
CAGE: K0680 — ROLLS-ROYCE AIRLINES (GBR)
SPECIFICATIONS
materialIRON ALLOY 660 OVERALL
head_styleDOUBLE HEXAGON EXTENDED WASHER
head_height0.320 INCHES MINIMUM AND 0.340 INCHES MAXIMUM IN
thread_class1A A
thread_length0.502 INCHES MINIMUM AND 0.522 INCHES MAXIMUM IN
fastener_length1.052 INCHES MINIMUM AND 1.072 INCHES MAXIMUM IN
thread_directionRIGHT-HAND
width_between_flats0.304 INCHES MINIMUM AND 0.313 INCHES MAXIMUM IN
nominal_thread_diameter0.250 INCHES IN
extended_washer_diameter0.428 INCHES MINIMUM AND 0.448 INCHES MAXIMUM IN
first_diameter_from_head0.246 INCHES MINIMUM AND 0.249 INCHES MAXIMUM IN
thread_quantity_per_inch28
NSN5306-00-879-3339
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: BLT1957 · 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
•
EXTENDED WASHER THICKNESS: 0.060 INCHES MINIMUM AND 0.070 INCHES MAXIMUM IN
•
HEAD HEIGHT: 0.320 INCHES MINIMUM AND 0.340 INCHES MAXIMUM IN
•
FASTENER LENGTH: 1.052 INCHES MINIMUM AND 1.072 INCHES MAXIMUM IN
•
EXTENDED WASHER DIAMETER: 0.428 INCHES MINIMUM AND 0.448 INCHES MAXIMUM IN
•
THREAD LENGTH: 0.502 INCHES MINIMUM AND 0.522 INCHES MAXIMUM IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 5731 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
FIRST DIAMETER FROM HEAD: 0.246 INCHES MINIMUM AND 0.249 INCHES MAXIMUM IN
•
DISTANCE FROM LARGEST BEARING SURFACE OF HEAD TO END OF SECOND DIAMETER: 0.530 INCHES MINIMUM AND 0.550 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS
EXTENDED WASHER THICKNESS0.060 INCHES MINIMUM AND 0.070 INCHES MAXIMUM IN
HEAD HEIGHT0.320 INCHES MINIMUM AND 0.340 INCHES MAXIMUM IN
FASTENER LENGTH1.052 INCHES MINIMUM AND 1.072 INCHES MAXIMUM IN
EXTENDED WASHER DIAMETER0.428 INCHES MINIMUM AND 0.448 INCHES MAXIMUM IN
THREAD LENGTH0.502 INCHES MINIMUM AND 0.522 INCHES MAXIMUM IN
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 5731 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
FIRST DIAMETER FROM HEAD0.246 INCHES MINIMUM AND 0.249 INCHES MAXIMUM IN
DISTANCE FROM LARGEST BEARING SURFACE OF HEAD TO END OF SECOND DIAMETER0.530 INCHES MINIMUM AND 0.550 INCHES MAXIMUM IN
NOMINAL THREAD DIAMETER0.250 INCHES IN
HEAD STYLEDOUBLE HEXAGON EXTENDED WASHER
OTHER ITEMS IN FSC 5306 — Bolts
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5306-00-001-1276 5306-00-001-1949 5306-00-001-1988 5306-00-001-1989 5306-00-001-1990 5306-00-001-1991 5306-00-001-1993 5306-00-001-2017
SUBSTITUTES & CROSS-REFERENCES 1
6863076Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
Ready to buy BLT1957?
Compare prices from verified sellers on eBay
Buy on eBay →
As an eBay Partner, PartsTable may earn a commission. Your price is not affected.
FREQUENTLY ASKED QUESTIONS
What is BLT1957?
BLT1957 is a BOLT,EXTERNALLY RELIEVED BODY.
What parts can replace BLT1957?
There is 1 known substitute for BLT1957: 6863076. Substitute compatibility should be verified for your specific system.
What is the NSN for BLT1957?
BLT1957 is cataloged in the U.S. Government catalog under NSN 5306-00-879-3339. This indicates validated use in U.S. government and defense supply chains.
Community Feedback
Leave a Comment
Comments are reviewed before appearing. You will receive an email to verify before your comment appears.

Request a Quote — BLT1957

✓ 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.