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XB-78 — SPRING,HELICAL,COMPRESSION

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

XB-78: SPRING,HELICAL,COMPRESSION.

The SPRING,HELICAL,COMPRESSION is a the manufacturer industrial component. Key specifications include material: STEEL OVERALL, head_style: FLAT CHAMFER, head_height: 0.306 INCHES MINIMUM AND 0.312 INCHES MAXIMUM IN, thread_class: 3A A, head_diameter: 0.457 INCHES MINIMUM AND 0.468 INCHES MAXIMUM IN, thread_length: 0.358 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5305-00-983-5344, 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
XB-78
NSN: 5305-00-983-5344
NIINs: 009835344, 014337878
FSC: 5305 — Screws
CAGE: 66289 — WISCONSIN MOTORS, LLC (USA)
SPECIFICATIONS
materialSTEEL OVERALL
head_styleFLAT CHAMFER
head_height0.306 INCHES MINIMUM AND 0.312 INCHES MAXIMUM IN
thread_class3A A
head_diameter0.457 INCHES MINIMUM AND 0.468 INCHES MAXIMUM IN
thread_length0.358 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN
fastener_length0.469 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN
hardness_rating36.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM OVERALL
thread_directionRIGHT-HAND
surface_treatmentCADMIUM AND CHROMATE OVERALL
width_across_flats0.250 INCHES MINIMUM AND 0.253 INCHES MAXIMUM IN
internal_drive_styleHEXAGON
NSN5305-00-983-5344
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: XB-78 · 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
•
WIDTH ACROSS FLATS: 0.250 INCHES MINIMUM AND 0.253 INCHES MAXIMUM IN
•
HEAD HEIGHT: 0.306 INCHES MINIMUM AND 0.312 INCHES MAXIMUM IN
•
FASTENER LENGTH: 0.469 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416 TY 2 CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
THREAD LENGTH: 0.358 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN
•
HARDNESS RATING: 36.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM OVERALL
•
NOMINAL THREAD DIAMETER: 0.312 INCHES IN
•
HEAD STYLE: FLAT CHAMFER
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS0.250 INCHES MINIMUM AND 0.253 INCHES MAXIMUM IN
HEAD HEIGHT0.306 INCHES MINIMUM AND 0.312 INCHES MAXIMUM IN
FASTENER LENGTH0.469 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416 TY 2 CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
THREAD LENGTH0.358 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN
HARDNESS RATING36.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM OVERALL
NOMINAL THREAD DIAMETER0.312 INCHES IN
HEAD STYLEFLAT CHAMFER
THREAD DIRECTIONRIGHT-HAND
NONDEFINITIVE SPEC/STD DATA6 TYPE
SUBSTITUTES & CROSS-REFERENCES 3
FF-S-86 REVISION CReference document
Same NSN cross-reference
Reference document — Identification reference
2CH418Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
MS16997-76Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LIFECYCLE
NSN statusCancelled· U.S. Government catalog
Acquisition advice: Terminal item — no further procurement; issued until stock is exhaustedNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is XB-78?
XB-78 is a SPRING,HELICAL,COMPRESSION.
What parts can replace XB-78?
There are 3 known substitutes for XB-78: FF-S-86 REVISION C, 2CH418, MS16997-76. Substitute compatibility should be verified for your specific system.
What is the NSN for XB-78?
XB-78 is cataloged in the U.S. Government catalog under NSN 5305-00-983-5344. This indicates validated use in U.S. government and defense supply chains.
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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.