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PartsTable / COMPONENT / FF571
FF571 ✓ Verified by PartsTable
— · BOLT SCREW
WHAT YOU NEED TO KNOW
Grade/class stamped on head determines strength Metric and imperial threads look similar — measure pitch
Verify thread pitch — metric != imperial
PRODUCT OVERVIEW

The BOLT,SQUARE NECK is a the manufacturer industrial component. Key specifications include material: STEEL OVERALL, head_style: BUTTON, neck_width: 0.250 INCHES NOMINAL IN, head_height: 0.125 INCHES NOMINAL IN, neck_length: 0.219 INCHES NOMINAL IN, thread_class: 2A A. This product is currently in active production with full OEM support.

This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 5306-00-527-3522, 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
FF571
NSN: 5306-00-527-3522
FSC: 5306
CAGE: 81348 — FEDERAL SPECIFICATIONS PROMULGATED BY GENERAL SERVICES ADMINISTRATION WASHINGTON DC (USA)
SPECIFICATIONS
materialSTEEL OVERALL
head_styleBUTTON
neck_width0.250 INCHES NOMINAL IN
head_height0.125 INCHES NOMINAL IN
neck_length0.219 INCHES NOMINAL IN
thread_class2A A
head_diameter0.563 INCHES NOMINAL IN
thread_length0.875 INCHES MINIMUM IN
fastener_length4.750 INCHES NOMINAL IN
thread_directionRIGHT-HAND
features_providedSQUARE NUT
nominal_thread_diameter0.250 INCHES IN
NSN5306-00-527-3522
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: FF571 · 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 QUANTITY PER INCH: 20
•
NECK LENGTH: 0.219 INCHES NOMINAL IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: FF-B-571 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
•
HEAD DIAMETER: 0.563 INCHES NOMINAL IN
•
NECK WIDTH: 0.250 INCHES NOMINAL IN
•
NOMINAL THREAD DIAMETER: 0.250 INCHES IN
•
HEAD HEIGHT: 0.125 INCHES NOMINAL IN
•
THREAD CLASS: 2A A
TECHNICAL CHARACTERISTICS (FLIS)
THREAD QUANTITY PER INCH20
NECK LENGTH0.219 INCHES NOMINAL IN
MATERIAL DOCUMENT AND CLASSIFICATIONFF-B-571 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
HEAD DIAMETER0.563 INCHES NOMINAL IN
NECK WIDTH0.250 INCHES NOMINAL IN
NOMINAL THREAD DIAMETER0.250 INCHES IN
HEAD HEIGHT0.125 INCHES NOMINAL IN
THREAD CLASS2A A
FASTENER LENGTH4.750 INCHES NOMINAL IN
HEAD STYLEBUTTON
VERIFIED SUBSTITUTES & CROSS-REFERENCES 4
120 23/32Interchangeable
interchangeable cross-reference
interchangeable
1314Interchangeable
interchangeable cross-reference
interchangeable
GGG-D-751Interchangeable
interchangeable cross-reference
interchangeable
70446Interchangeable
interchangeable cross-reference
interchangeable
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is FF571?
FF571 is a BOLT,SQUARE NECK.
What parts can replace FF571?
There are 4 known substitutes for FF571: 120 23/32, 1314, GGG-D-751 and 1 more. Substitute compatibility should be verified for your specific system.
What is the NSN for FF571?
FF571 is cataloged in the Federal Logistics Information System (FLIS) under NSN 5306-00-527-3522. This indicates validated use in U.S. government and defense supply chains.
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✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026