PartsTable
Technical Data Sheet
Download PDF

RDB20 — NUT,SELF-LOCKING,EXTENDED WASHER

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

RDB20: NUT,SELF-LOCKING,EXTENDED WASHER.

NUT,SELF-LOCKING,EXTENDED WASHER. Key specifications include material: STEEL COMP 1020 OVERALL, nut_style: HEXAGON, thread_class: 2B, thread_series: UNF, overall_height: 0.750 INCHES NOMINAL IN, hardness_rating: 55.0 ROCKWELL C MINIMUM AND 60.0 ROCKWELL C MAXIMUM. This part is cataloged in the U.S.

Government catalog under NSN 5310-00-264-0479, 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
RDB20
NSN: 5310-00-264-0479
FSC: 5310 — Nuts and Washers
CAGE: 02978 — RENK AMERICA LLC DIV RENK AMERICA (USA)
SPECIFICATIONS
materialSTEEL COMP 1020 OVERALL
nut_styleHEXAGON
thread_class2B
thread_seriesUNF
overall_height0.750 INCHES NOMINAL IN
hardness_rating55.0 ROCKWELL C MINIMUM AND 60.0 ROCKWELL C MAXIMUM
locking_featurePREVAILING TORQUE ALL METAL DESIGN
thread_directionRIGHT-HAND
washer_thickness0.188 INCHES NOMINAL IN
features_providedCASEHARDENED
width_across_flats1.250 INCHES NOMINAL IN
nominal_thread_size0.875 INCHES IN
NSN5310-00-264-0479
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: RDB20 · 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
•
WASHER OUTSIDE DIAMETER: 1.719 INCHES NOMINAL IN
•
WIDTH ACROSS FLATS: 1.250 INCHES NOMINAL IN
•
THREAD SERIES: UNF
•
HARDNESS RATING: 55.0 ROCKWELL C MINIMUM AND 60.0 ROCKWELL C MAXIMUM
•
WASHER THICKNESS: 0.188 INCHES NOMINAL IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: SAE ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
FEATURES PROVIDED: CASEHARDENED
TECHNICAL CHARACTERISTICS
OVERALL HEIGHT0.750 INCHES NOMINAL IN
WASHER OUTSIDE DIAMETER1.719 INCHES NOMINAL IN
WIDTH ACROSS FLATS1.250 INCHES NOMINAL IN
THREAD SERIESUNF
HARDNESS RATING55.0 ROCKWELL C MINIMUM AND 60.0 ROCKWELL C MAXIMUM
WASHER THICKNESS0.188 INCHES NOMINAL IN
MATERIAL DOCUMENT AND CLASSIFICATIONSAE ASSN STD SINGLE MATERIAL RESPONSE OVERALL
FEATURES PROVIDEDCASEHARDENED
THREAD DIRECTIONRIGHT-HAND
NOMINAL THREAD SIZE0.875 INCHES IN
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 1
RC30-20Reference document
Same NSN cross-reference
Reference document — Secondary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Semi-active item — no replacement plannedNo demilitarization required
Ready to buy RDB20?
Compare prices from verified sellers on eBay
Buy on eBay →
As an eBay Partner, PartsTable may earn a commission. Your price is not affected.
FREQUENTLY ASKED QUESTIONS
What is RDB20?
RDB20 is a NUT,SELF-LOCKING,EXTENDED WASHER.
What parts can replace RDB20?
There is 1 known substitute for RDB20: RC30-20. Substitute compatibility should be verified for your specific system.
What is the NSN for RDB20?
RDB20 is cataloged in the U.S. Government catalog under NSN 5310-00-264-0479. This indicates validated use in U.S. government and defense supply chains.
Community Feedback
Leave a Comment
Comments are reviewed before appearing. You will receive an email to verify before your comment appears.

Request a Quote — RDB20

✓ 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.