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Technical Data Sheet
PartsTable / COMPONENT / A1-4826
A1-4826 ✓ 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 SCREW,EXTERNALLY RELIEVED BODY is a the manufacturer industrial component. Key specifications include material: STEEL COMP 4340 OVERALL, head_style: DEE CHAMFER, head_height: 0.189 INCHES MINIMUM AND 0.205 INCHES MAXIMUM IN, thread_class: 2A A, head_diameter: 0.389 INCHES MINIMUM AND 0.393 INCHES MAXIMUM IN, thread_direction: RIGHT-HAND. This product is currently in active production with full OEM support.

This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 5305-00-979-8987, 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
A1-4826
NSN: 5305-00-979-8987
FSC: 5305
CAGE: 31949 — BROOKS AUTOMATION, INC. DIV CTI CRYOGENICS (USA)
SPECIFICATIONS
materialSTEEL COMP 4340 OVERALL
head_styleDEE CHAMFER
head_height0.189 INCHES MINIMUM AND 0.205 INCHES MAXIMUM IN
thread_class2A A
head_diameter0.389 INCHES MINIMUM AND 0.393 INCHES MAXIMUM IN
thread_directionRIGHT-HAND
internal_drive_styleCROSS RECESS TYPE 1
nominal_thread_diameter0.250 INCHES IN
first_diameter_from_head0.250 INCHES NOMINAL IN
third_diameter_from_head0.250 INCHES MAXIMUM IN
thread_quantity_per_inch20
thread_series_designatorUNIFIED NATIONAL COARSE (UNC)
NSN5305-00-979-8987
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: A1-4826 · 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
•
FOURTH DIAMETER FROM HEAD: 0.186 INCHES MINIMUM AND 0.194 INCHES MAXIMUM IN
•
HEAD DIAMETER: 0.389 INCHES MINIMUM AND 0.393 INCHES MAXIMUM IN
•
DISTANCE FROM CENTERLINE TO FLAT: 0.154 INCHES MINIMUM AND 0.156 INCHES MAXIMUM IN
•
HEAD HEIGHT: 0.189 INCHES MINIMUM AND 0.205 INCHES MAXIMUM IN
•
SECOND DIAMETER FROM HEAD: 0.197 INCHES MINIMUM AND 0.205 INCHES MAXIMUM IN
•
NOMINAL THREAD DIAMETER: 0.250 INCHES IN
•
THREAD QUANTITY PER INCH: 20
•
THREAD DIRECTION: RIGHT-HAND
TECHNICAL CHARACTERISTICS (FLIS)
FOURTH DIAMETER FROM HEAD0.186 INCHES MINIMUM AND 0.194 INCHES MAXIMUM IN
HEAD DIAMETER0.389 INCHES MINIMUM AND 0.393 INCHES MAXIMUM IN
DISTANCE FROM CENTERLINE TO FLAT0.154 INCHES MINIMUM AND 0.156 INCHES MAXIMUM IN
HEAD HEIGHT0.189 INCHES MINIMUM AND 0.205 INCHES MAXIMUM IN
SECOND DIAMETER FROM HEAD0.197 INCHES MINIMUM AND 0.205 INCHES MAXIMUM IN
NOMINAL THREAD DIAMETER0.250 INCHES IN
THREAD QUANTITY PER INCH20
THREAD DIRECTIONRIGHT-HAND
PART NAME ASSIGNED BY CONTROLLING AGENCYNAVY SPECIAL PROJECT
DISTANCE FROM LARGEST BEARING SURFACE OF HEAD TO END OF FOURTH DIAMETER2.148 INCHES MINIMUM AND 2.196 INCHES MAXIMUM IN
VERIFIED SUBSTITUTES & CROSS-REFERENCES 3
17X40Interchangeable
interchangeable cross-reference
interchangeable
391B1Interchangeable
interchangeable cross-reference
interchangeable
394826Interchangeable
Same NIIN cross-reference
interchangeable
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is A1-4826?
A1-4826 is a SCREW,EXTERNALLY RELIEVED BODY.
What parts can replace A1-4826?
There are 3 known substitutes for A1-4826: 17X40, 391B1, 394826. Substitute compatibility should be verified for your specific system.
What is the NSN for A1-4826?
A1-4826 is cataloged in the Federal Logistics Information System (FLIS) under NSN 5305-00-979-8987. 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