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Technical Data Sheet
PartsTable / COMPONENT / 1665-21-3
1665-21-3 ✓ 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 STUD,SHOULDERED is a the manufacturer industrial component. Key specifications include material: STEEL, thread_length: 1.218 INCHES MAXIMUM NUT THREAD IN, overall_length: 3.125 INCHES NOMINAL IN, hardness_rating: 18.0 ROCKWELL C MINIMUM AND 28.0 ROCKWELL C MAXIMUM, shoulder_length: 0.188 INCHES NOMINAL IN, special_features: 0.125 IN. RADIUS BETWEEN WRENCH FLAT SHOULDER AND NUT END IN.

This product is currently in active production with full OEM support. This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 5307-00-637-1408, 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
1665-21-3
NSN: 5307-00-637-1408
FSC: 5307
CAGE: 20076 — TITAN WHEEL CORPORATION OF ILLINOIS (USA)
SPECIFICATIONS
materialSTEEL
thread_length1.218 INCHES MAXIMUM NUT THREAD IN
overall_length3.125 INCHES NOMINAL IN
hardness_rating18.0 ROCKWELL C MINIMUM AND 28.0 ROCKWELL C MAXIMUM
shoulder_length0.188 INCHES NOMINAL IN
special_features0.125 IN. RADIUS BETWEEN WRENCH FLAT SHOULDER AND NUT END IN
style_designatorSHOULDERED
thread_directionRIGHT-HAND NUT THREAD
shoulder_diameter1.125 INCHES MINIMUM AND 1.218 INCHES MAXIMUM IN
nominal_thread_size0.750 INCHES STUD THREAD IN
nut_end_shank_length0.625 INCHES NOMINAL IN
distance_across_flats0.938 INCHES NOMINAL IN
NSN5307-00-637-1408
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 1665-21-3 · 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
•
THREAD DIRECTION: RIGHT-HAND STUD THREAD
•
STYLE DESIGNATOR: SHOULDERED
•
NUT END SHANK LENGTH: 0.625 INCHES NOMINAL IN
•
NOMINAL THREAD SIZE: 0.750 INCHES NUT THREAD IN
•
SHOULDER LENGTH: 0.188 INCHES NOMINAL IN
•
NUT END SHANK DIAMETER: 0.783 INCHES MINIMUM AND 0.786 INCHES MAXIMUM IN
•
THREAD QUANTITY PER INCH: 16 STUD THREAD
TECHNICAL CHARACTERISTICS (FLIS)
THREAD DIRECTIONRIGHT-HAND STUD THREAD
OVERALL LENGTH3.125 INCHES NOMINAL IN
STYLE DESIGNATORSHOULDERED
NUT END SHANK LENGTH0.625 INCHES NOMINAL IN
NOMINAL THREAD SIZE0.750 INCHES NUT THREAD IN
SHOULDER LENGTH0.188 INCHES NOMINAL IN
NUT END SHANK DIAMETER0.783 INCHES MINIMUM AND 0.786 INCHES MAXIMUM IN
THREAD QUANTITY PER INCH16 STUD THREAD
DISTANCE ACROSS FLATS0.938 INCHES NOMINAL IN
THREAD SERIES DESIGNATORUNS NUT THREAD
VERIFIED SUBSTITUTES & CROSS-REFERENCES 19
T146Interchangeable
interchangeable cross-reference
interchangeable
111T146Interchangeable
interchangeable cross-reference
interchangeable
306-0940-000Interchangeable
interchangeable cross-reference
interchangeable
SL5665PC27Interchangeable
interchangeable cross-reference
interchangeable
021085-00Interchangeable
interchangeable cross-reference
interchangeable
SL5891PC27Interchangeable
interchangeable cross-reference
interchangeable
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is 1665-21-3?
1665-21-3 is a STUD,SHOULDERED.
What parts can replace 1665-21-3?
There are 19 known substitutes for 1665-21-3: T146, 111T146, 306-0940-000 and 16 more. Substitute compatibility should be verified for your specific system.
What is the NSN for 1665-21-3?
1665-21-3 is cataloged in the Federal Logistics Information System (FLIS) under NSN 5307-00-637-1408. This indicates validated use in U.S. government and defense supply chains.
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✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026