PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

21251Washer,finishing

Mason Electric Co. Dba Mason Controls · NSN 5310-00-685-1618 · FSC 5310 · No Item Name Available
Verified by PartsTable
NSN 5310-00-685-1618 — this item is cataloged by the U.S. Government under National Stock Number 5310-00-685-1618. Primary manufacturer part number: 21251.
Features
  • Washer,finishing — FSC 5310
  • Surface Treatment: CADMIUM OVERALL
  • Material: STEEL OVERALL
  • Style Designator: FINISHING
  • Outside Diameter: 0.255 INCHES MAXIMUM IN
  • Hole Diameter: 0.125 INCHES MINIMUM AND 0.130 INCHES MAXIMUM IN
  • Material Thickness: 0.031 INCHES NOMINAL IN
  • 4 verified cross-references
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
  • Applications requiring Steel Overall construction
General Description

The Washer,finishing, cataloged under National Stock Number 5310-00-685-1618, is classified within Federal Supply Class 5310 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is Mason Electric Co. Dba Mason Controls. Government technical data includes 6 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 4 commercial cross-references from 4 manufacturers, enabling identification through both NSN and commercial part number lookups. 9 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5310-00-685-1618
Primary Part Number21251
Item NameWasher,finishing
FSC / FSG5310 / 53 — No Item Name Available
ManufacturerMason Electric Co. Dba Mason Controls
StatusACTIVE
Surface TreatmentCADMIUM OVERALL
MaterialSTEEL OVERALL
Style DesignatorFINISHING
Outside Diameter0.255 INCHES MAXIMUM IN
Hole Diameter0.125 INCHES MINIMUM AND 0.130 INCHES MAXIMUM IN
Material Thickness0.031 INCHES NOMINAL IN
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 9
5110-00-255-6557 INTERCHANGEABLE
Reamer,hand
5985-00-399-7135ESD3362-4 INTERCHANGEABLE
Mast Section
Us Army Communications & Electronics Materiel Readiness Command Logistics Engineering Dir
1660-00-881-030621251 INTERCHANGEABLE
Converter,liquid Oxygen
Ingersoll-Rand Company Dba Ingersoll-Rand
4520-01-020-3263 INTERCHANGEABLE
Heating Element,electrical,nonim
5305-01-158-676521251 INTERCHANGEABLE
Setscrew
Erie Strayer Co
2910-01-168-8088J8123050 INTERCHANGEABLE
Float,carburetor
Chrysler Corp Engine and Components Sales Diversified Products Div
4730-01-231-862121251 INTERCHANGEABLE
Adapter,straight,tube to Boss
Stanadyne Corporation Dba Stanadyne Diesel Systems Div Diesel Systems
5305-01-298-062921251 INTERCHANGEABLE
Screw,cap,hexagon Head
Industrial Technologies and Services Llc
6105-01-300-647221251-2 INTERCHANGEABLE
Motor,alternating Current
Silver King Refrigeration Inc.
Cross-Reference Index
Part NumberManufacturer
PY0046 Phaostron Instrument and Electronic Company (USA)
21251 PRIMARY Mason Electric Co. Dba Mason Controls (USA)
21251 Unison Industries Llc (USA)
21251 Amphenol Corp Div Amphenol Aerospace Operations (USA)
Related Parts
5110-00-255-6557INTERCHANGEABLE
REAMER,HAND
5985-00-399-7135INTERCHANGEABLE
MAST SECTION
ESD3362-4
1660-00-881-0306INTERCHANGEABLE
CONVERTER,LIQUID OXYGEN
21251
4520-01-020-3263INTERCHANGEABLE
HEATING ELEMENT,ELECTRICAL,NONIM
5305-01-158-6765INTERCHANGEABLE
SETSCREW
21251
2910-01-168-8088INTERCHANGEABLE
FLOAT,CARBURETOR
J8123050
4730-01-231-8621INTERCHANGEABLE
ADAPTER,STRAIGHT,TUBE TO BOSS
21251
5305-01-298-0629INTERCHANGEABLE
SCREW,CAP,HEXAGON HEAD
21251
6105-01-300-6472INTERCHANGEABLE
MOTOR,ALTERNATING CURRENT
21251-2

Frequently Asked Questions

What is NSN 5310-00-685-1618?

NSN 5310-00-685-1618 is a Washer,finishing, manufactured by Mason Electric Co. Dba Mason Controls, classified under FSC 5310 (No Item Name Available). Status: active.

What are the part numbers for NSN 5310-00-685-1618?

NSN 5310-00-685-1618 has 4 cross-referenced part numbers: PY0046 (Phaostron Instrument and Electronic Company), 21251 (Mason Electric Co. Dba Mason Controls), 21251 (Unison Industries Llc), 21251 (Amphenol Corp Div Amphenol Aerospace Operations).

What NSN replaces 5310-00-685-1618?

There are 9 known substitutes for 5310-00-685-1618: 5110-00-255-6557, 5985-00-399-7135, 1660-00-881-0306 and 6 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 21251?

Key specifications for 21251: Overall Height: 0.078 INCHES NOMINAL IN; Surface Treatment: CADMIUM OVERALL; Material: STEEL OVERALL; Style Designator: FINISHING. 7 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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