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GB510BC4-18 — SCREW,CLOSE TOLERANCE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

GB510BC4-18: SCREW,CLOSE TOLERANCE.

The SCREW,CLOSE TOLERANCE is a the manufacturer industrial component. Key specifications include material: STEEL COMP H11 OVERALL, head_style: FLAT COUNTERSUNK, grip_length: 1.115 INCHES MINIMUM AND 1.135 INCHES MAXIMUM IN, thread_class: 3A A, grip_diameter: 0.2483 INCHES MINIMUM AND 0.2492 INCHES MAXIMUM IN, head_diameter: 0.447 INCHES MINIMUM AND 0.507 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-01-136-7151, 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
GB510BC4-18
NSN: 5305-01-136-7151
FSC: 5305 — Screws
CAGE: 26512 — NORTHROP GRUMMAN SYSTEMS CORPORATION (USA)
SPECIFICATIONS
materialSTEEL COMP H11 OVERALL
head_styleFLAT COUNTERSUNK
grip_length1.115 INCHES MINIMUM AND 1.135 INCHES MAXIMUM IN
thread_class3A A
grip_diameter0.2483 INCHES MINIMUM AND 0.2492 INCHES MAXIMUM IN
head_diameter0.447 INCHES MINIMUM AND 0.507 INCHES MAXIMUM IN
thread_length0.386 INCHES MINIMUM AND 0.453 INCHES MAXIMUM IN
surface_finish32.0 MICROINCHES GRIP
fastener_length1.521 INCHES MINIMUM AND 1.568 INCHES MAXIMUM IN
hardness_rating46.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM OVERALL
thread_directionRIGHT-HAND
countersink_angle99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM
NSN5305-01-136-7151
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: GB510BC4-18 · 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: 32.0 MICROINCHES GRIP
•
FASTENER LENGTH: 1.521 INCHES MINIMUM AND 1.568 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: NAS 672 ASSN STD 1ST TREATMENT RESPONSE OR MIL-C-8837 TY 2 CL 2 MIL SPEC 2ND TREATMENT RESPONSE OVERALL
•
THREAD LENGTH: 0.386 INCHES MINIMUM AND 0.453 INCHES MAXIMUM IN
•
HARDNESS RATING: 46.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM OVERALL
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 6487 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
NOMINAL THREAD DIAMETER: 0.250 INCHES IN
•
HEAD STYLE: FLAT COUNTERSUNK
TECHNICAL CHARACTERISTICS
SURFACE FINISH32.0 MICROINCHES GRIP
FASTENER LENGTH1.521 INCHES MINIMUM AND 1.568 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONNAS 672 ASSN STD 1ST TREATMENT RESPONSE OR MIL-C-8837 TY 2 CL 2 MIL SPEC 2ND TREATMENT RESPONSE OVERALL
THREAD LENGTH0.386 INCHES MINIMUM AND 0.453 INCHES MAXIMUM IN
HARDNESS RATING46.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM OVERALL
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 6487 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
NOMINAL THREAD DIAMETER0.250 INCHES IN
HEAD STYLEFLAT COUNTERSUNK
THREAD DIRECTIONRIGHT-HAND
GRIP LENGTH1.115 INCHES MINIMUM AND 1.135 INCHES MAXIMUM IN
OTHER ITEMS IN FSC 5305 — Screws
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5305-00-001-5016 5305-00-001-9160 5305-00-001-9629 5305-00-001-9742 5305-00-001-9768 5305-00-003-4306 5305-00-003-6694 5305-00-003-6753
SUBSTITUTES & CROSS-REFERENCES 3
H148-4-18Reference document
Same NSN cross-reference
Reference document — Secondary reference
HT8171-4-18Reference document
Same NSN cross-reference
Reference document — Secondary reference
106706H-4-A18Reference 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 GB510BC4-18?
GB510BC4-18 is a SCREW,CLOSE TOLERANCE.
What parts can replace GB510BC4-18?
There are 3 known substitutes for GB510BC4-18: H148-4-18, HT8171-4-18, 106706H-4-A18. Substitute compatibility should be verified for your specific system.
What is the NSN for GB510BC4-18?
GB510BC4-18 is cataloged in the U.S. Government catalog under NSN 5305-01-136-7151. 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.