PartsTable
Technical Data Sheet
PartsTable / COMPONENT / L691/51 ITEM 21
L691/51 ITEM 21 ✓ Verified by PartsTable
— · BOLT SCREW
WHAT YOU NEED TO KNOW
Grade/class stamped on head determines strength Metric and imperial threads look similar — measure pitch
Verify thread pitch — metric != imperial
PRODUCT OVERVIEW

The L691/51 ITEM 21 is a the manufacturer industrial component. This product is currently in active production with full OEM support. This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 5325-01-315-1647, 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
L691/51 ITEM 21
NSN: 5325-01-315-1647
FSC: 5325
CAGE: 0JKF4 — ULSTEIN USA INC (USA)
SPECIFICATIONS
Part NumberL691/51 ITEM 21
NSN5325-01-315-1647
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: L691/51 ITEM 21 · 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
•
CROSS-SECTIONAL SHAPE STYLE: RECTANGULAR
•
MATERIAL: STEEL
•
MAJOR THICKNESS: 2.0 MILLIMETERS NOMINAL MM
•
OUTSIDE DIAMETER: 55.10 MILLIMETERS MINIMUM AND 55.74 MILLIMETERS MAXIMUM MM
•
CASEHARDENING INDICATOR: NOT CASEHARDENED
•
USAGE DESIGN: INTERNAL
•
MATERIAL HARDNESS RATING: 435.0 VICKERS MINIMUM AND 530.0 VICKERS MAXIMUM
•
RING STYLE: INTERNAL
TECHNICAL CHARACTERISTICS (FLIS)
CROSS-SECTIONAL SHAPE STYLERECTANGULAR
MATERIALSTEEL
MAJOR THICKNESS2.0 MILLIMETERS NOMINAL MM
OUTSIDE DIAMETER55.10 MILLIMETERS MINIMUM AND 55.74 MILLIMETERS MAXIMUM MM
CASEHARDENING INDICATORNOT CASEHARDENED
USAGE DESIGNINTERNAL
MATERIAL HARDNESS RATING435.0 VICKERS MINIMUM AND 530.0 VICKERS MAXIMUM
RING STYLEINTERNAL
VERIFIED SUBSTITUTES & CROSS-REFERENCES 16
269PInterchangeable
interchangeable cross-reference
interchangeable
839-1-34Interchangeable
interchangeable cross-reference
interchangeable
8894287Interchangeable
interchangeable cross-reference
interchangeable
E345Interchangeable
interchangeable cross-reference
interchangeable
984704-1Interchangeable
interchangeable cross-reference
interchangeable
16964Interchangeable
interchangeable cross-reference
interchangeable
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
Ready to buy L691/51 ITEM 21?
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 L691/51 ITEM 21?
L691/51 ITEM 21 is a L691/51 ITEM 21.
What parts can replace L691/51 ITEM 21?
There are 16 known substitutes for L691/51 ITEM 21: 269P, 839-1-34, 8894287 and 13 more. Substitute compatibility should be verified for your specific system.
What is the NSN for L691/51 ITEM 21?
L691/51 ITEM 21 is cataloged in the Federal Logistics Information System (FLIS) under NSN 5325-01-315-1647. This indicates validated use in U.S. government and defense supply chains.
Community Feedback
Comments (0)
No comments yet. Be the first to share what you know.
Leave a Comment
Comments are reviewed before appearing. You will receive an email to verify before your comment appears.

Request a Quote — L691/51 ITEM 21

✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026