PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

803-1385637-03X-11Nut,plain,hexagon

Naval Ship Systems Command · NSN 5310-01-521-1020 · FSC 5310 · No Item Name Available
Verified by PartsTable
NSN 5310-01-521-1020 — this item is cataloged by the U.S. Government under National Stock Number 5310-01-521-1020. Primary manufacturer part number: 803-1385637-03X-11.
Features
  • Nut,plain,hexagon — FSC 5310
  • Material: NICKEL ALLOY OVERALL
  • Bearing Surface Type: FLAT
  • Material Document and Classification: ASTM-B164-2003 ASSN STD 1ST MATERIAL RESPONSE OVERALL
  • Nominal Thread Size: 0.675 INCHES IN
  • Thread Series: UNIFIED NATIONAL COARSE (UNC)
  • Thread Class: 2B
  • Nut Height: 0.375 INCHES NOMINAL IN
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
  • Applications requiring Nickel Alloy Overall construction
General Description

The Nut,plain,hexagon, cataloged under National Stock Number 5310-01-521-1020, is classified within Federal Supply Class 5310 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is Naval Ship Systems Command. Government technical data includes 11 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 4 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 11 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5310-01-521-1020
Primary Part Number803-1385637-03X-11
Item NameNut,plain,hexagon
FSC / FSG5310 / 53 — No Item Name Available
ManufacturerNaval Ship Systems Command
StatusACTIVE
MaterialNICKEL ALLOY OVERALL
Bearing Surface TypeFLAT
Material Document and ClassificationASTM-B164-2003 ASSN STD 1ST MATERIAL RESPONSE OVERALL
Nominal Thread Size0.675 INCHES IN
Thread SeriesUNIFIED NATIONAL COARSE (UNC)
Thread Class2B
Nut Height0.375 INCHES NOMINAL IN
Nut StyleHEXAGON
Width Across Flats1.063 INCHES NOMINAL IN
Thread DirectionRIGHT-HAND
Thread Quantity Per Inch11
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 11
4820-00-058-36301385637-052AF INTERCHANGEABLE
Valve,check
Naval Ship Systems Command
4820-00-878-4325803-1385637-082 INTERCHANGEABLE
Valve,check
Naval Ship Systems Command
4820-01-072-1204803-1385637-04X-17 INTERCHANGEABLE
Disk,valve
Naval Ship Systems Command
4820-01-426-24601260-014K800 INTERCHANGEABLE
Valve,check
Milwaukee Valve Co, Inc Div Milwaukee Valve Company, Llc
4820-01-435-5880803-1385637-05X-20 INTERCHANGEABLE
Disk,valve
Naval Ship Systems Command
5310-01-487-7109803-1385637-06X-22 INTERCHANGEABLE
Washer,flat
Naval Ship Systems Command
5310-01-487-7137803-1385637-02X-22 INTERCHANGEABLE
Washer,flat
Naval Ship Systems Command
5310-01-487-8128803-1385637-05X-22 INTERCHANGEABLE
Washer,flat
Naval Ship Systems Command
5310-01-521-1009803-1385637-10X-11 INTERCHANGEABLE
Nut,plain,hexagon
Naval Ship Systems Command
5310-01-521-1025803-1385637-05X-11 INTERCHANGEABLE
Nut,plain,hexagon
Naval Ship Systems Command
Cross-Reference Index
Part NumberManufacturer
999-78-3-9 Pima Valve, Llc (USA)
999-78-3-9 Hunt Valve Company, Inc. (USA)
1385637 Naval Ship Systems Command (USA)
803-1385637-03X-11 PRIMARY Naval Ship Systems Command (USA)
Related Parts
4820-00-058-3630INTERCHANGEABLE
VALVE,CHECK
1385637-052AF
4820-00-878-4325INTERCHANGEABLE
VALVE,CHECK
803-1385637-082
4820-01-072-1204INTERCHANGEABLE
DISK,VALVE
803-1385637-04X-17
4820-01-426-2460INTERCHANGEABLE
VALVE,CHECK
1260-014K800
4820-01-435-5880INTERCHANGEABLE
DISK,VALVE
803-1385637-05X-20
5310-01-487-7109INTERCHANGEABLE
WASHER,FLAT
803-1385637-06X-22
5310-01-487-7137INTERCHANGEABLE
WASHER,FLAT
803-1385637-02X-22
5310-01-487-8128INTERCHANGEABLE
WASHER,FLAT
803-1385637-05X-22
5310-01-521-1009INTERCHANGEABLE
NUT,PLAIN,HEXAGON
803-1385637-10X-11
5310-01-521-1025INTERCHANGEABLE
NUT,PLAIN,HEXAGON
803-1385637-05X-11
4820-01-540-8802INTERCHANGEABLE
SEAT,VALVE
803-1385637-08X-08

Frequently Asked Questions

What is NSN 5310-01-521-1020?

NSN 5310-01-521-1020 is a Nut,plain,hexagon, manufactured by Naval Ship Systems Command, classified under FSC 5310 (No Item Name Available). Status: active.

What are the part numbers for NSN 5310-01-521-1020?

NSN 5310-01-521-1020 has 4 cross-referenced part numbers: 999-78-3-9 (Pima Valve, Llc), 999-78-3-9 (Hunt Valve Company, Inc.), 1385637 (Naval Ship Systems Command), 803-1385637-03X-11 (Naval Ship Systems Command).

What NSN replaces 5310-01-521-1020?

There are 11 known substitutes for 5310-01-521-1020: 4820-00-058-3630, 4820-00-878-4325, 4820-01-072-1204 and 8 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 803-1385637-03X-11?

Key specifications for 803-1385637-03X-11: End Item Identification: SWING CHECK VALVE; Material: NICKEL ALLOY OVERALL; Bearing Surface Type: FLAT; Material Document and Classification: ASTM-B164-2003 ASSN STD 1ST MATERIAL RESPONSE OVERALL. 12 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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