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B121-5 — B121-5

✓ Government record, cited
— · MRO · MRO_GENERAL
PRODUCT OVERVIEW

B121-5: B121-5.

The B121-5 is a the manufacturer industrial component. Key specifications include material: STEEL COMP 303 OR STEEL COMP 303SE OVERALL, thickness: 0.250 INCHES NOMINAL IN, corner_shape: SQUARE ALL CORNERS, hole_diameter: 0.406 INCHES NOMINAL IN, overall_length: 0.4980 INCHES MINIMUM AND 0.5020 INCHES MAXIMUM IN, overall_diameter: 1.625 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 5310-00-709-7259, 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
MRO→ MRO_GENERAL→ B121-5
NSN: 5310-00-709-7259
NIINs: 007097259, 011321291, 015553340
FSC: 5310 — Nuts and Washers
CAGE: 78165 — SPRING PERCH CO INC (USA)
SPECIFICATIONS
materialSTEEL COMP 303 OR STEEL COMP 303SE OVERALL
thickness0.250 INCHES NOMINAL IN
corner_shapeSQUARE ALL CORNERS
hole_diameter0.406 INCHES NOMINAL IN
overall_length0.4980 INCHES MINIMUM AND 0.5020 INCHES MAXIMUM IN
overall_diameter1.625 INCHES NOMINAL IN
style_designatorSOLID, PLAIN, NO OUTSIDE FLANGES
surface_treatmentPASSIVATE OVERALL
body_inside_diameter0.3750 INCHES MINIMUM AND 0.3800 INCHES MAXIMUM IN
body_outside_diameter0.5570 INCHES MINIMUM AND 0.5670 INCHES MAXIMUM IN
peripheral_shape_styleROUND
center_hole_shape_styleROUND
NSN5310-00-709-7259
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: B121-5 · OEM ⚠ VERIFY BEFORE ORDERING Grade matters for torque spec — don't mix grades. A Grade 5 nut on a Grade 8 bolt weakens the joint. Lock nuts, wing nuts, and castle nuts are NOT interchangeable with standard hex ✓ BROKER TIP Match nut to bolt thread class and material. Stainless bolt + zinc nut = galvanic corrosion. Always verify finish matches (plain, zinc, hot-dip galvanized) PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
OVERALL DIAMETER: 1.625 INCHES NOMINAL IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-S-634 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
•
CROSS-SECTIONAL SHAPE STYLE: RECTANGULAR
•
PERIPHERAL SHAPE STYLE: ROUND
•
MATERIAL: STEEL COMP 1010 OVERALL
•
CENTER HOLE SHAPE STYLE: ROUND
•
HOLE DIAMETER: 0.406 INCHES NOMINAL IN
•
THICKNESS: 0.250 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
OVERALL DIAMETER1.625 INCHES NOMINAL IN
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-S-634 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
CROSS-SECTIONAL SHAPE STYLERECTANGULAR
PERIPHERAL SHAPE STYLEROUND
MATERIALSTEEL COMP 1010 OVERALL
CENTER HOLE SHAPE STYLEROUND
HOLE DIAMETER0.406 INCHES NOMINAL IN
THICKNESS0.250 INCHES NOMINAL IN
SUBSTITUTES & CROSS-REFERENCES 2
7097259Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
418489Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is B121-5?
B121-5 is a B121-5. It is classified as a MRO (MRO_GENERAL).
What parts can replace B121-5?
There are 2 known substitutes for B121-5: 7097259, 418489. Substitute compatibility should be verified for your specific system.
What is the NSN for B121-5?
B121-5 is cataloged in the U.S. Government catalog under NSN 5310-00-709-7259. 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.