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BACB30MS5R21 — SCREW,CLOSE TOLERANCE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

BACB30MS5R21: SCREW,CLOSE TOLERANCE.

The SCREW,CLOSE TOLERANCE is a the manufacturer industrial component. Key specifications include material: TITANIUM ALLOY UNS R56400 OVERALL, head_style: FLAT COUNTERSUNK, grip_length: 1.302 INCHES MINIMUM AND 1.322 INCHES MAXIMUM IN, thread_class: 3A A, grip_diameter: 0.3427 INCHES MINIMUM AND 0.3432 INCHES MAXIMUM IN, head_diameter: 0.586 INCHES MINIMUM AND 0.637 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-01-337-3286, 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
BACB30MS5R21
NSN: 5305-01-337-3286
FSC: 5305 — Screws
CAGE: 81205 — THE BOEING COMPANY DIV DEFENSE (USA)
SPECIFICATIONS
materialTITANIUM ALLOY UNS R56400 OVERALL
head_styleFLAT COUNTERSUNK
grip_length1.302 INCHES MINIMUM AND 1.322 INCHES MAXIMUM IN
thread_class3A A
grip_diameter0.3427 INCHES MINIMUM AND 0.3432 INCHES MAXIMUM IN
head_diameter0.586 INCHES MINIMUM AND 0.637 INCHES MAXIMUM IN
thread_length0.469 INCHES NOMINAL IN
surface_finish32.0 MICROINCHES THREADS
fastener_length1.766 INCHES MINIMUM AND 1.796 INCHES MAXIMUM IN
special_featuresRED DYE OR PAINT ON THREAD END BEFORE LUBRICATION
thread_directionRIGHT-HAND
countersink_angle99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM
NSN5305-01-337-3286
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: BACB30MS5R21 · 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: BAC 5861,CAGE81205 MFR REF SINGLE TREATMENT RESPONSE OVERALL
•
THREAD LENGTH: 0.469 INCHES NOMINAL IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 4928 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 4967 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
NOMINAL THREAD DIAMETER: 0.312 INCHES IN
TECHNICAL CHARACTERISTICS
SURFACE FINISH32.0 MICROINCHES THREADS
SURFACE FINISH32.0 MICROINCHES GRIP
SURFACE FINISH63.0 MICROINCHES BEARING SURFACE OF HEAD
FASTENER LENGTH1.766 INCHES MINIMUM AND 1.796 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONBAC 5861,CAGE81205 MFR REF SINGLE TREATMENT RESPONSE OVERALL
THREAD LENGTH0.469 INCHES NOMINAL IN
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 4928 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 4967 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
NOMINAL THREAD DIAMETER0.312 INCHES IN
FEATURES PROVIDEDCETYL ALCOHOL LUBRICANT
HEAD STYLEFLAT COUNTERSUNK
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

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 BACB30MS5R21?
BACB30MS5R21 is a SCREW,CLOSE TOLERANCE.
What is the NSN for BACB30MS5R21?
BACB30MS5R21 is cataloged in the U.S. Government catalog under NSN 5305-01-337-3286. 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.