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121673-4-28 — BOLT,CLOSE TOLERANCE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

121673-4-28: BOLT,CLOSE TOLERANCE.

The BOLT,CLOSE TOLERANCE is a the manufacturer industrial component. Key specifications include head_style: UNDERCUT HEXAGON, grip_length: 1.750 INCHES MINIMUM AND 1.766 INCHES MAXIMUM IN, head_height: 0.126 INCHES MINIMUM AND 0.141 INCHES MAXIMUM IN, thread_class: 3A A, grip_diameter: 0.2483 INCHES MINIMUM AND 0.2492 INCHES MAXIMUM IN, thread_length: 0.282 INCHES MINIMUM AND 0.333 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5306-01-047-7844, 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
121673-4-28
NSN: 5306-01-047-7844
FSC: 5306 — Bolts
CAGE: 80539 — SPS TECHNOLOGIES, LLC DBA AEROSPACE FASTENERS GROUP DIV AEROSPACE - SANTA ANA (USA)
SPECIFICATIONS
materialSTEEL COMP E4340 OR STEEL COMP 4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OR STEEL COMP 4130 OR STEEL COMP 6150 OVERALL
head_styleUNDERCUT HEXAGON
grip_length1.750 INCHES MINIMUM AND 1.766 INCHES MAXIMUM IN
head_height0.126 INCHES MINIMUM AND 0.141 INCHES MAXIMUM IN
thread_class3A A
grip_diameter0.2483 INCHES MINIMUM AND 0.2492 INCHES MAXIMUM IN
thread_length0.282 INCHES MINIMUM AND 0.333 INCHES MAXIMUM IN
surface_finish63.0 MICROINCHES GRIP
fastener_length2.168 INCHES MINIMUM AND 2.188 INCHES MAXIMUM IN
hardness_rating36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM OVERALL
special_featuresRETAINING RING IN SHANK
thread_directionRIGHT-HAND
NSN5306-01-047-7844
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 121673-4-28 · 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
•
SURFACE FINISH: 63.0 MICROINCHES GRIP
•
HEAD HEIGHT: 0.126 INCHES MINIMUM AND 0.141 INCHES MAXIMUM IN
•
FASTENER LENGTH: 2.168 INCHES MINIMUM AND 2.188 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416,TYPE 2,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
THREAD LENGTH: 0.282 INCHES MINIMUM AND 0.333 INCHES MAXIMUM IN
•
HARDNESS RATING: 36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM OVERALL
•
NOMINAL THREAD DIAMETER: 0.250 INCHES IN
TECHNICAL CHARACTERISTICS
SURFACE FINISH63.0 MICROINCHES GRIP
SURFACE FINISH63.0 MICROINCHES BEARING SURFACE OF HEAD
HEAD HEIGHT0.126 INCHES MINIMUM AND 0.141 INCHES MAXIMUM IN
FASTENER LENGTH2.168 INCHES MINIMUM AND 2.188 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416,TYPE 2,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
THREAD LENGTH0.282 INCHES MINIMUM AND 0.333 INCHES MAXIMUM IN
HARDNESS RATING36.0 ROCKWELL C MINIMUM AND 40.0 ROCKWELL C MAXIMUM OVERALL
NOMINAL THREAD DIAMETER0.250 INCHES IN
HEAD STYLEUNDERCUT HEXAGON
THREAD DIRECTIONRIGHT-HAND
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

No substitute or cross-reference records for this part.

LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 121673-4-28?
121673-4-28 is a BOLT,CLOSE TOLERANCE.
What is the NSN for 121673-4-28?
121673-4-28 is cataloged in the U.S. Government catalog under NSN 5306-01-047-7844. 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.