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668999 — BOLT,MACHINE

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

668999: BOLT,MACHINE.

The BOLT,MACHINE is a the manufacturer industrial component. Key specifications include material: NICKEL ALLOY OVERALL, hole_type: DRILLED, head_style: DOUBLE HEXAGON W/HOLE, grip_length: 1.950 INCHES MINIMUM AND 1.990 INCHES MAXIMUM IN, head_height: 0.328 INCHES MINIMUM AND 0.348 INCHES MAXIMUM IN, thread_class: 1A A. This part is cataloged in the U.S.

Government catalog under NSN 5306-00-481-6223, 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
668999
NSN: 5306-00-481-6223
FSC: 5306 — Bolts
CAGE: 77445 — RTX CORPORATION DBA PRATT & WHITNEY DIV PRATT &WHITNEY (USA)
SPECIFICATIONS
materialNICKEL ALLOY OVERALL
hole_typeDRILLED
head_styleDOUBLE HEXAGON W/HOLE
grip_length1.950 INCHES MINIMUM AND 1.990 INCHES MAXIMUM IN
head_height0.328 INCHES MINIMUM AND 0.348 INCHES MAXIMUM IN
thread_class1A A
hole_diameter0.070 INCHES NOMINAL IN
hole_quantity4
thread_length0.375 INCHES MINIMUM AND 0.435 INCHES MAXIMUM IN
fastener_length2.365 INCHES MINIMUM AND 2.385 INCHES MAXIMUM IN
hardness_rating32.0 ROCKWELL C MINIMUM AND 42.0 ROCKWELL C MAXIMUM OVERALL
special_featuresSHANK RELIEVED TO 0.286 IN. MIN,0.276 IN. MAX DIA,DISTANCE FROM HEAD 0.615 IN. MIN,0.635 IN. MAX TO 1.340 IN. MIN,1.360 IN. MAX IN
NSN5306-00-481-6223
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: 668999 · 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
•
EXTENDED WASHER THICKNESS: 0.070 INCHES MINIMUM IN
•
HEAD HEIGHT: 0.328 INCHES MINIMUM AND 0.348 INCHES MAXIMUM IN
•
FASTENER LENGTH: 2.365 INCHES MINIMUM AND 2.385 INCHES MAXIMUM IN
•
EXTENDED WASHER DIAMETER: 0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
•
THREAD LENGTH: 0.375 INCHES MINIMUM AND 0.435 INCHES MAXIMUM IN
•
HARDNESS RATING: 32.0 ROCKWELL C MINIMUM AND 42.0 ROCKWELL C MAXIMUM OVERALL
•
HOLE CONFIGURATION STYLE: ROUND LONGITUDINAL HOLE
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 5708 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
TECHNICAL CHARACTERISTICS
EXTENDED WASHER THICKNESS0.070 INCHES MINIMUM IN
HEAD HEIGHT0.328 INCHES MINIMUM AND 0.348 INCHES MAXIMUM IN
FASTENER LENGTH2.365 INCHES MINIMUM AND 2.385 INCHES MAXIMUM IN
EXTENDED WASHER DIAMETER0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
THREAD LENGTH0.375 INCHES MINIMUM AND 0.435 INCHES MAXIMUM IN
HARDNESS RATING32.0 ROCKWELL C MINIMUM AND 42.0 ROCKWELL C MAXIMUM OVERALL
HOLE CONFIGURATION STYLEROUND LONGITUDINAL HOLE
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 5708 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
NOMINAL THREAD DIAMETER0.312 INCHES IN
FEATURES PROVIDEDFINISHED HEAD
OTHER ITEMS IN FSC 5306 — Bolts
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5306-00-004-7044 5306-00-007-6129 5306-00-008-7899 5306-00-009-4739 5306-00-118-7332 5306-00-151-1777 5306-00-255-4507 5306-01-101-2459
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 668999?
668999 is a BOLT,MACHINE.
What is the NSN for 668999?
668999 is cataloged in the U.S. Government catalog under NSN 5306-00-481-6223. 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.