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RB21739 — WASHER,KEYWAY

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

RB21739: WASHER,KEYWAY.

The WASHER,KEYWAY is a the manufacturer industrial component. Key specifications include material: STEEL COMP 630 OVERALL, hole_diameter: 0.377 INCHES MINIMUM AND 0.378 INCHES MAXIMUM IN, surface_finish: 12.0 MICROINCHES TOP, outside_diameter: 0.855 INCHES NOMINAL IN, surface_treatment: CHROMIUM OVERALL, material_thickness: 0.126 INCHES MINIMUM AND 0.128 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5310-00-883-2957, 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
RB21739
NSN: 5310-00-883-2957
FSC: 5310 — Nuts and Washers
CAGE: 51663 — HYDRO-AIRE AEROSPACE CORP. DBA LEAR ROMEC DIV LEAR ROMEC (USA)
SPECIFICATIONS
materialSTEEL COMP 630 OVERALL
hole_diameter0.377 INCHES MINIMUM AND 0.378 INCHES MAXIMUM IN
surface_finish12.0 MICROINCHES TOP
outside_diameter0.855 INCHES NOMINAL IN
surface_treatmentCHROMIUM OVERALL
material_thickness0.126 INCHES MINIMUM AND 0.128 INCHES MAXIMUM IN
internal_keyway_width0.096 INCHES MINIMUM AND 0.098 INCHES MAXIMUM IN
internal_keyway_quantity2
material_document_and_classificationASTM A320-63 GR L10 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationQQ-C-320 CL 2E FED SPEC SINGLE TREATMENT RESPONSE OVERALL
distance_from_centerline_to_bottom_of_internal_keyway0.255 INCHES MINIMUM AND 0.260 INCHES MAXIMUM IN
NSN5310-00-883-2957
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: RB21739 · OEM ⚠ VERIFY BEFORE ORDERING Grade matters for torque spec — don't mix grades. A Grade 5 nut on a Grade 8 bolt weakens the joint. Lock nuts, wing nuts, and castle nuts are NOT interchangeable with standard hex ✓ BROKER TIP Match nut to bolt thread class and material. Stainless bolt + zinc nut = galvanic corrosion. Always verify finish matches (plain, zinc, hot-dip galvanized) PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
DISTANCE FROM CENTERLINE TO BOTTOM OF INTERNAL KEYWAY: 0.255 INCHES MINIMUM AND 0.260 INCHES MAXIMUM IN
•
INTERNAL KEYWAY WIDTH: 0.096 INCHES MINIMUM AND 0.098 INCHES MAXIMUM IN
•
SURFACE FINISH: 12.0 MICROINCHES BOTTOM
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-C-320 CL 2E FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
MATERIAL DOCUMENT AND CLASSIFICATION: ASTM A320-63 GR L10 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
OUTSIDE DIAMETER: 0.855 INCHES NOMINAL IN
•
INTERNAL KEYWAY QUANTITY: 2
TECHNICAL CHARACTERISTICS
DISTANCE FROM CENTERLINE TO BOTTOM OF INTERNAL KEYWAY0.255 INCHES MINIMUM AND 0.260 INCHES MAXIMUM IN
INTERNAL KEYWAY WIDTH0.096 INCHES MINIMUM AND 0.098 INCHES MAXIMUM IN
SURFACE FINISH12.0 MICROINCHES BOTTOM
SURFACE FINISH12.0 MICROINCHES TOP
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-C-320 CL 2E FED SPEC SINGLE TREATMENT RESPONSE OVERALL
MATERIAL DOCUMENT AND CLASSIFICATIONASTM A320-63 GR L10 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
OUTSIDE DIAMETER0.855 INCHES NOMINAL IN
INTERNAL KEYWAY QUANTITY2
MATERIAL THICKNESS0.126 INCHES MINIMUM AND 0.128 INCHES MAXIMUM IN
SURFACE TREATMENTCHROMIUM OVERALL
OTHER ITEMS IN FSC 5310 — Nuts and Washers
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5310-00-000-0040 5310-00-000-0077 5310-00-000-0079 5310-00-000-1146 5310-00-000-3815 5310-00-000-4532 5310-00-000-4540
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 RB21739?
RB21739 is a WASHER,KEYWAY.
What is the NSN for RB21739?
RB21739 is cataloged in the U.S. Government catalog under NSN 5310-00-883-2957. 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.