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BACB30LU5-21 — SCREW,CLOSE TOLERANCE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

BACB30LU5-21: SCREW,CLOSE TOLERANCE.

The SCREW,CLOSE TOLERANCE is a the manufacturer industrial component. Key specifications include material: STEEL COMP 8740 OR STEEL COMP E4340 OVERALL, head_style: FLAT COUNTERSUNK, grip_length: 1.302 INCHES MINIMUM AND 1.322 INCHES MAXIMUM IN, thread_class: 3A A, grip_diameter: 0.3110 INCHES MINIMUM AND 0.3120 INCHES MAXIMUM IN, head_diameter: 0.574 INCHES MINIMUM AND 0.637 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-01-045-2903, 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
BACB30LU5-21
NSN: 5305-01-045-2903
FSC: 5305 — Screws
CAGE: 81205 — THE BOEING COMPANY DIV DEFENSE (USA)
SPECIFICATIONS
materialSTEEL COMP 8740 OR STEEL COMP E4340 OVERALL
head_styleFLAT COUNTERSUNK
grip_length1.302 INCHES MINIMUM AND 1.322 INCHES MAXIMUM IN
thread_class3A A
grip_diameter0.3110 INCHES MINIMUM AND 0.3120 INCHES MAXIMUM IN
head_diameter0.574 INCHES MINIMUM AND 0.637 INCHES MAXIMUM IN
thread_length0.444 INCHES MINIMUM AND 0.494 INCHES MAXIMUM IN
surface_finish32.0 MICROINCHES THREADS
fastener_length1.766 INCHES MINIMUM AND 1.796 INCHES MAXIMUM IN
thread_directionRIGHT-HAND
countersink_angle100.0 DEGREES NOMINAL
surface_treatmentCADMIUM AND CHROMATE OVERALL
NSN5305-01-045-2903
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: BACB30LU5-21 · 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 THREADS
•
FASTENER LENGTH: 1.766 INCHES MINIMUM AND 1.796 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416,TYPE 2,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
THREAD LENGTH: 0.444 INCHES MINIMUM AND 0.494 INCHES MAXIMUM IN
•
NOMINAL THREAD DIAMETER: 0.312 INCHES IN
•
HEAD STYLE: FLAT COUNTERSUNK
•
THREAD DIRECTION: RIGHT-HAND
TECHNICAL CHARACTERISTICS
SURFACE FINISH32.0 MICROINCHES THREADS
SURFACE FINISH32.0 MICROINCHES GRIP
FASTENER LENGTH1.766 INCHES MINIMUM AND 1.796 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416,TYPE 2,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
THREAD LENGTH0.444 INCHES MINIMUM AND 0.494 INCHES MAXIMUM IN
NOMINAL THREAD DIAMETER0.312 INCHES IN
HEAD STYLEFLAT COUNTERSUNK
THREAD DIRECTIONRIGHT-HAND
GRIP LENGTH1.302 INCHES MINIMUM AND 1.322 INCHES MAXIMUM IN
GRIP DIAMETER0.3110 INCHES MINIMUM AND 0.3120 INCHES MAXIMUM IN
OTHER ITEMS IN FSC 5305 — Screws
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5305-00-000-0094 5305-00-000-1397 5305-00-000-2625 5305-00-000-3669 5305-00-000-3830 5305-00-000-3831
SUBSTITUTES & CROSS-REFERENCES

No substitute or cross-reference records for this part.

LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is BACB30LU5-21?
BACB30LU5-21 is a SCREW,CLOSE TOLERANCE.
What is the NSN for BACB30LU5-21?
BACB30LU5-21 is cataloged in the U.S. Government catalog under NSN 5305-01-045-2903. 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.