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421566 — SCREW,MACHINE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

421566: SCREW,MACHINE.

The SCREW,MACHINE is a the manufacturer industrial component. Key specifications include head_style: ROUND, head_height: 0.067 INCHES MINIMUM AND 0.078 INCHES MAXIMUM IN, thread_class: 2A A, head_diameter: 0.169 INCHES MINIMUM AND 0.187 INCHES MAXIMUM IN, thread_length: 0.750 INCHES MAXIMUM IN, screw_material: STEEL COMP 1020. This part is cataloged in the U.S.

Government catalog under NSN 5305-00-591-9231, 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
421566
NSN: 5305-00-591-9231
FSC: 5305 — Screws
CAGE: 21450 — ARMY WEAPONS COMMAND ATTN AMSWE-REE-S (USA)
SPECIFICATIONS
head_styleROUND
head_height0.067 INCHES MINIMUM AND 0.078 INCHES MAXIMUM IN
thread_class2A A
head_diameter0.169 INCHES MINIMUM AND 0.187 INCHES MAXIMUM IN
thread_length0.750 INCHES MAXIMUM IN
screw_materialSTEEL COMP 1020
fastener_length0.750 INCHES MAXIMUM IN
thread_directionRIGHT-HAND
internal_drive_styleSLOT
nominal_thread_diameter0.099 INCHES IN
screw_surface_treatmentCADMIUM OR ZINC
thread_quantity_per_inch48
NSN5305-00-591-9231
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 421566 · 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
•
HEAD HEIGHT: 0.067 INCHES MINIMUM AND 0.078 INCHES MAXIMUM IN
•
SCREW SURFACE TREATMENT: CADMIUM OR ZINC
•
FASTENER LENGTH: 0.750 INCHES MAXIMUM IN
•
SCREW MATERIAL DOCUMENT AND CLASSIFICATION: QQ-S-634 FED SPEC SINGLE MATERIAL RESPONSE
•
THREAD LENGTH: 0.750 INCHES MAXIMUM IN
•
NOMINAL THREAD DIAMETER: 0.099 INCHES IN
•
HEAD STYLE: ROUND
•
THREAD DIRECTION: RIGHT-HAND
TECHNICAL CHARACTERISTICS
HEAD HEIGHT0.067 INCHES MINIMUM AND 0.078 INCHES MAXIMUM IN
SCREW SURFACE TREATMENTCADMIUM OR ZINC
FASTENER LENGTH0.750 INCHES MAXIMUM IN
SCREW MATERIAL DOCUMENT AND CLASSIFICATIONQQ-S-634 FED SPEC SINGLE MATERIAL RESPONSE
THREAD LENGTH0.750 INCHES MAXIMUM IN
NOMINAL THREAD DIAMETER0.099 INCHES IN
HEAD STYLEROUND
THREAD DIRECTIONRIGHT-HAND
NONDEFINITIVE SPEC/STD DATA1 TYPE AND 1S STYLE
SCREW MATERIALSTEEL COMP 1020
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 1
P180785Reference document
Same NSN cross-reference
Reference document — Secondary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 421566?
421566 is a SCREW,MACHINE.
What parts can replace 421566?
There is 1 known substitute for 421566: P180785. Substitute compatibility should be verified for your specific system.
What is the NSN for 421566?
421566 is cataloged in the U.S. Government catalog under NSN 5305-00-591-9231. 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.