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877B-3MB-31 — STUD,LOCKED IN

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

877B-3MB-31: STUD,LOCKED IN.

The STUD,LOCKED IN is a the manufacturer industrial component. Key specifications include material: STEEL COMP 4130, thread_class: 3A NUT THREAD A, thread_length: 0.275 INCHES NOMINAL STUD THREAD IN, overall_length: 0.927 INCHES MINIMUM AND 0.947 INCHES MAXIMUM IN, hardness_rating: 26.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM, locking_feature: RING, LOCK KEYED. This part is cataloged in the U.S.

Government catalog under NSN 5307-00-936-9670, 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
877B-3MB-31
NSN: 5307-00-936-9670
FSC: 5307 — Studs
CAGE: 75237 — HOWMET GLOBAL FASTENING SYSTEMS INC. DIV MICRODOT PRODUCTS (USA)
SPECIFICATIONS
materialSTEEL COMP 4130
thread_class3A NUT THREAD A
thread_length0.275 INCHES NOMINAL STUD THREAD IN
overall_length0.927 INCHES MINIMUM AND 0.947 INCHES MAXIMUM IN
hardness_rating26.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM
locking_featureRING, LOCK KEYED
shoulder_length0.032 INCHES MINIMUM AND 0.042 INCHES MAXIMUM IN
style_designatorLOCKED IN
thread_directionRIGHT-HAND STUD THREAD
shoulder_diameter0.183 INCHES MINIMUM AND 0.193 INCHES MAXIMUM IN
surface_treatmentCADMIUM OVERALL
nominal_thread_size0.250 INCHES STUD THREAD IN
NSN5307-00-936-9670
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 877B-3MB-31 · 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 LENGTH: 0.275 INCHES NOMINAL STUD THREAD IN
•
HARDNESS RATING: 26.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM
•
STYLE DESIGNATOR: LOCKED IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: MIL-S-6758 MIL SPEC SINGLE MATERIAL RESPONSE
•
THREAD DIRECTION: RIGHT-HAND STUD THREAD
TECHNICAL CHARACTERISTICS
THREAD LENGTH0.275 INCHES NOMINAL STUD THREAD IN
THREAD LENGTH0.427 INCHES MINIMUM AND 0.447 INCHES MAXIMUM NUT THREAD IN
HARDNESS RATING26.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM
STYLE DESIGNATORLOCKED IN
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-S-6758 MIL SPEC SINGLE MATERIAL RESPONSE
OVERALL LENGTH0.927 INCHES MINIMUM AND 0.947 INCHES MAXIMUM IN
THREAD DIRECTIONRIGHT-HAND STUD THREAD
THREAD DIRECTIONRIGHT-HAND NUT THREAD
NOMINAL THREAD SIZE0.250 INCHES STUD THREAD IN
NOMINAL THREAD SIZE0.190 INCHES NUT THREAD IN
OTHER ITEMS IN FSC 5307 — Studs
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5307-00-000-6436 5307-00-001-1578 5307-00-001-1761 5307-00-001-2366 5307-00-001-4491 5307-00-001-4624 5307-00-001-4625
SUBSTITUTES & CROSS-REFERENCES 1
S234-3-510AReference document
Same NSN cross-reference
Reference document — Secondary reference
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 877B-3MB-31?
877B-3MB-31 is a STUD,LOCKED IN.
What parts can replace 877B-3MB-31?
There is 1 known substitute for 877B-3MB-31: S234-3-510A. Substitute compatibility should be verified for your specific system.
What is the NSN for 877B-3MB-31?
877B-3MB-31 is cataloged in the U.S. Government catalog under NSN 5307-00-936-9670. 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.