PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

21056ANut,plain,castellated,hexagon

Brinkley Technology Group Llc Dba Hercules Manufacturing · NSN 5310-00-274-7731 · FSC 5310 · No Item Name Available
Verified by PartsTable
NSN 5310-00-274-7731 — this item is cataloged by the U.S. Government under National Stock Number 5310-00-274-7731. Primary manufacturer part number: 21056A.
Features
  • Nut,plain,castellated,hexagon — FSC 5310
  • Nut Style: CASTELLATED, HEXAGON
  • Width Across Flats: 0.612 INCHES MINIMUM AND 0.625 INCHES MAXIMUM IN
  • Thread Quantity Per Inch: 20
  • Thread Class: 3B
  • Thread Direction: RIGHT-HAND
  • Nut Height: 0.448 INCHES MINIMUM AND 0.458 INCHES MAXIMUM IN
  • Bearing Surface Type: WASHER FACED
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
  • Applications requiring Steel Comp 3140 or Steel Comp 2330 or Steel Comp 4135 or Steel Comp 4140 or Steel Comp 4037 Overall construction
General Description

The Nut,plain,castellated,hexagon, cataloged under National Stock Number 5310-00-274-7731, is classified within Federal Supply Class 5310 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is Brinkley Technology Group Llc Dba Hercules Manufacturing. Government technical data includes 11 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 26 commercial cross-references from 21 manufacturers, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN5310-00-274-7731
Primary Part Number21056A
Item NameNut,plain,castellated,hexagon
FSC / FSG5310 / 53 — No Item Name Available
ManufacturerBrinkley Technology Group Llc Dba Hercules Manufacturing
StatusCANCELLED
Nut StyleCASTELLATED, HEXAGON
Width Across Flats0.612 INCHES MINIMUM AND 0.625 INCHES MAXIMUM IN
Thread Quantity Per Inch20
Thread Class3B
Thread DirectionRIGHT-HAND
Nut Height0.448 INCHES MINIMUM AND 0.458 INCHES MAXIMUM IN
Bearing Surface TypeWASHER FACED
Material Document and ClassificationSAE ASSN STD 1ST MATERIAL RESPONSE OR SAE ASSN STD 2ND MATERIAL RESPONSE OR SAE ASSN STD 3RD MATERIAL RESPONSE OR SAE ASSN STD 4TH MATERIAL RESPONSE OR AISI ASSN STD 5TH MATERIAL RESPONSE OVERALL
MaterialSTEEL COMP 3140 OR STEEL COMP 2330 OR STEEL COMP 4135 OR STEEL COMP 4140 OR STEEL COMP 4037 OVERALL
Nominal Thread Size0.438 INCHES IN
Thread SeriesUNF
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 12
5998-00-009-7089 INTERCHANGEABLE
Circuit Card Assembly
1630-00-093-962857020 INTERCHANGEABLE
Sleeve
Honeywell International Inc. Dba Honeywell Div Aerospace-South Bend (westmoor St)
5120-00-198-5392 INTERCHANGEABLE
Key,socket Head Screw
3455-00-236-363520080 INTERCHANGEABLE
Reamer,machine
Brown & Sharpe, Inc. Div Precision Measuring Instruments, Tesa Usa
7195-00-240-4455 INTERCHANGEABLE
Aquarium
5305-00-271-2944 INTERCHANGEABLE
Screw,machine
3020-00-854-5814 INTERCHANGEABLE
Link,roller Chain
5325-00-889-973221342 INTERCHANGEABLE
Insert,screw Thread
Mason Electric Co. Dba Mason Controls
5962-01-102-5314538766-1 INTERCHANGEABLE
Microcircuit,memory
Raytheon Company Dba Raytheon
5330-01-145-315516404 INTERCHANGEABLE
Seal,plain Encased
Skf Usa Inc. Dba Skf Aerospace Sealing Solutions
Cross-Reference Index
Part NumberManufacturer
21342 Hyster-Yale Group, Inc. Div Hyster-Yale Materials Handling (USA)
72MBS1 Linde Material Handling North America Corporation (USA)
21056A PRIMARY Brinkley Technology Group Llc Dba Hercules Manufacturing (USA)
21056 0mcc Inc (USA)
72MBS1 Linde Lift Truck Corp. (USA)
21056A Cyclone Drill Co (USA)
6D07 Clark Material Handling Company (USA)
272071 Mitsubishi Caterpillar Forklift America, Inc (USA)
21056A Clark Material Handling Company (USA)
HM21056A Clark Equipment Co (USA)
L12161 Towmotor Corp Dallas Plant Sub of Caterpillar Tractor Co (USA)
21056A O K Machinery Div of Motter John C Printing Press Co (USA)
904322 New Holland Construction (USA)
6D07 Clark Equipment Co (USA)
21342 Hyster-Yale Group, Inc. (USA)
21056A PRIMARY Drs Naval Power Systems Inc Dba Drs Power & Control Technologies Inc (USA)
21056A PRIMARY Hoist Liftruck Mfg Inc (USA)
643449 Sasco Inc Canadian Div
16044 Celtrac Corp (USA)
1A9673 PRIMARY Napco International Llc Dba Napco International Inc (USA)
Related Parts
5998-00-009-7089INTERCHANGEABLE
CIRCUIT CARD ASSEMBLY
1630-00-093-9628INTERCHANGEABLE
SLEEVE
57020
5120-00-198-5392INTERCHANGEABLE
KEY,SOCKET HEAD SCREW
3455-00-236-3635INTERCHANGEABLE
REAMER,MACHINE
20080
7195-00-240-4455INTERCHANGEABLE
AQUARIUM
5305-00-271-2944INTERCHANGEABLE
SCREW,MACHINE
3020-00-854-5814INTERCHANGEABLE
LINK,ROLLER CHAIN
5325-00-889-9732INTERCHANGEABLE
INSERT,SCREW THREAD
21342
5962-01-102-5314INTERCHANGEABLE
MICROCIRCUIT,MEMORY
538766-1
5330-01-145-3155INTERCHANGEABLE
SEAL,PLAIN ENCASED
16404
5330-01-220-8275INTERCHANGEABLE
RETAINER,SEAL
21342
4720-01-389-3389INTERCHANGEABLE
HOSE,NONMETALLIC
21342

Frequently Asked Questions

What is NSN 5310-00-274-7731?

NSN 5310-00-274-7731 is a Nut,plain,castellated,hexagon, manufactured by Brinkley Technology Group Llc Dba Hercules Manufacturing, classified under FSC 5310 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 5310-00-274-7731?

NSN 5310-00-274-7731 has 26 cross-referenced part numbers: 21342 (Hyster-Yale Group, Inc. Div Hyster-Yale Materials Handling), 72MBS1 (Linde Material Handling North America Corporation), 21056A (Brinkley Technology Group Llc Dba Hercules Manufacturing), 21056 (0mcc Inc), 72MBS1 (Linde Lift Truck Corp.) and 21 more.

What NSN replaces 5310-00-274-7731?

There are 12 known substitutes for 5310-00-274-7731: 5998-00-009-7089, 1630-00-093-9628, 5120-00-198-5392 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 21056A?

Key specifications for 21056A: Nut Style: CASTELLATED, HEXAGON; Width Across Flats: 0.612 INCHES MINIMUM AND 0.625 INCHES MAXIMUM IN; Thread Quantity Per Inch: 20; Thread Class: 3B. 11 total characteristics are documented in the Federal Logistics Information System.

Is NSN 5310-00-274-7731 still in active supply?

NSN 5310-00-274-7731 is currently cancelled. Check with the Defense Logistics Agency for current availability and authorized substitutes.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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