PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

20521Seat,helical Compression Spring

Eaton Corporation Dba Airframe Div Fuel & Motion Control Systems · NSN 5340-01-124-4585 · FSC 5340 · No Item Name Available
Verified by PartsTable
NSN 5340-01-124-4585 — this item is cataloged by the U.S. Government under National Stock Number 5340-01-124-4585. Primary manufacturer part number: 20521.
Features
  • Seat,helical Compression Spring — FSC 5340
  • First Step Diameter: 1.9920 INCHES MINIMUM AND 1.9960 INCHES MAXIMUM IN
  • Countersink Diameter: 1.3750 INCHES NOMINAL IN
  • End Diameter: 1.7150 INCHES NOMINAL IN
  • Design Type: SOLID
  • Style Designator: SEAT
  • Surface Treatment Document and Classification: MIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE
  • Material Document and Classification: AMS 4120 ASSN STD SINGLE MATERIAL RESPONSE
Applications
  • Mechanical energy storage
  • Vibration dampening
  • Return mechanism operation
  • Applications requiring Aluminum Alloy 2024 construction
General Description

The Seat,helical Compression Spring, cataloged under National Stock Number 5340-01-124-4585, is classified within Federal Supply Class 5340 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is Eaton Corporation Dba Airframe Div Fuel & Motion Control Systems. Government technical data includes 11 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 1 commercial cross-reference from 1 manufacturer, enabling identification through both NSN and commercial part number lookups. 6 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5340-01-124-4585
Primary Part Number20521
Item NameSeat,helical Compression Spring
FSC / FSG5340 / 53 — No Item Name Available
ManufacturerEaton Corporation Dba Airframe Div Fuel & Motion Control Systems
StatusACTIVE
First Step Diameter1.9920 INCHES MINIMUM AND 1.9960 INCHES MAXIMUM IN
Countersink Diameter1.3750 INCHES NOMINAL IN
End Diameter1.7150 INCHES NOMINAL IN
Design TypeSOLID
Style DesignatorSEAT
Surface Treatment Document and ClassificationMIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE
Material Document and ClassificationAMS 4120 ASSN STD SINGLE MATERIAL RESPONSE
MaterialALUMINUM ALLOY 2024
Surface TreatmentANODIZE
Countersink Angle in Deg90.0
Bore Diameter1.6250 INCHES NOMINAL IN
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 6
Clip,spring Tension
4730-00-277-53095710S1-8 INTERCHANGEABLE
Plug,pipe
The Walworth Company
5945-00-883-683713217E4066-1 INTERCHANGEABLE
Relay,electromagnetic
Cecom Lr Center
5331-01-171-631020521 INTERCHANGEABLE
O-Ring
Electro Impulse Laboratory Inc Dba Electro Impulse Inc
4710-01-176-089120714 INTERCHANGEABLE
Tube,metallic
Alcoa/reynolds Metals Company
5310-01-391-2749 INTERCHANGEABLE
Nut,self-Locking,hexagon
Cross-Reference Index
Part NumberManufacturer
20521 PRIMARY Eaton Corporation Dba Airframe Div Fuel & Motion Control Systems (USA)
Related Parts
5340-00-559-8763SUCCESSOR
CLIP,SPRING TENSION
4730-00-277-5309INTERCHANGEABLE
PLUG,PIPE
5710S1-8
5945-00-883-6837INTERCHANGEABLE
RELAY,ELECTROMAGNETIC
13217E4066-1
5331-01-171-6310INTERCHANGEABLE
O-RING
20521
4710-01-176-0891INTERCHANGEABLE
TUBE,METALLIC
20714
5310-01-391-2749INTERCHANGEABLE
NUT,SELF-LOCKING,HEXAGON

Frequently Asked Questions

What is NSN 5340-01-124-4585?

NSN 5340-01-124-4585 is a Seat,helical Compression Spring, manufactured by Eaton Corporation Dba Airframe Div Fuel & Motion Control Systems, classified under FSC 5340 (No Item Name Available). Status: active.

What are the part numbers for NSN 5340-01-124-4585?

NSN 5340-01-124-4585 has 1 cross-referenced part number: 20521 (Eaton Corporation Dba Airframe Div Fuel & Motion Control Systems).

What NSN replaces 5340-01-124-4585?

There are 6 known substitutes for 5340-01-124-4585: 5340-00-559-8763, 4730-00-277-5309, 5945-00-883-6837 and 3 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 20521?

Key specifications for 20521: First Step Diameter: 1.9920 INCHES MINIMUM AND 1.9960 INCHES MAXIMUM IN; Countersink Diameter: 1.3750 INCHES NOMINAL IN; End Diameter: 1.7150 INCHES NOMINAL IN; Design Type: SOLID. 11 total characteristics are documented in the Federal Logistics Information System.

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