PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

103903-1Valve,regulating,fluid Pressure

Rtx Corporation Div Pratt & Whitney · NSN 4820-00-146-1952 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-00-146-1952 — this item is cataloged by the U.S. Government under National Stock Number 4820-00-146-1952. Primary manufacturer part number: 103903-1.
Features
  • Valve,regulating,fluid Pressure — FSC 4820
  • Second End Seat Angle in Deg: 12.0
  • First End Seat Angle in Deg: 37.0
  • Third End Style Designator: GASKET SEAL
  • Second End Outside Diameter Tube Accommodated: 0.125 INCHES NOMINAL IN
  • Temp Rating: -65.0 FAHRENHEIT MINIMUM AND 400.0 FAHRENHEIT MAXIMUM DEGF
  • Third End Thread Direction: RIGHT-HAND
  • Thread Size and Series/type Designator: 5/16-24 UNIFIED NATIONAL JOINT FINE (UNJF) MODIFIED SECOND END
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
General Description

The Valve,regulating,fluid Pressure, cataloged under National Stock Number 4820-00-146-1952, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is Rtx Corporation Div Pratt & Whitney. Government technical data includes 24 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 5 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
NSN4820-00-146-1952
Primary Part Number103903-1
Item NameValve,regulating,fluid Pressure
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerRtx Corporation Div Pratt & Whitney
StatusACTIVE
Second End Seat Angle in Deg12.0
First End Seat Angle in Deg37.0
Third End Style DesignatorGASKET SEAL
Second End Outside Diameter Tube Accommodated0.125 INCHES NOMINAL IN
Temp Rating-65.0 FAHRENHEIT MINIMUM AND 400.0 FAHRENHEIT MAXIMUM DEGF
Third End Thread DirectionRIGHT-HAND
Thread Size and Series/type Designator5/16-24 UNIFIED NATIONAL JOINT FINE (UNJF) MODIFIED SECOND END
First End Outside Diameter Tube Accommodated0.250 INCHES NOMINAL IN
FilterNOT INCLUDED
End Connection Quantity3
Third End Relationship with Preceding EndsNOT IDENTICAL WITH FIRST OR SECOND END
Third End Thread Class2B
Flow Control DevicePOPPET
Second End Style DesignatorFLARELESS
Thread Size and Series/type Designator1/4-32 UNEF THIRD END
Body StyleTEE
Regulation TypeAUTOMATIC DOUBLE STAGE
Thread Size and Series/type Designator7/16-20 UNF FIRST END
Valve Stem DesignDOUBLE SEAT
Valve Loading MethodSPRING
First End Thread Class3A A
Second End Relationship with First EndNOT IDENTICAL
Second End Thread Class3A A
First End Style DesignatorFLARED
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 11
5950-00-265-5618 INTERCHANGEABLE
Coil,radio Frequency
5310-00-268-75192658 INTERCHANGEABLE
Nut,plain,hexagon
Telemechanics Inc
5130-00-674-9212 INTERCHANGEABLE
Bit,screwdriver
5325-00-839-94062658 INTERCHANGEABLE
Receptacle,special
Avibank Mfg., Inc. Dba Avibank Manufacturing Inc
5970-00-841-3026 INTERCHANGEABLE
Insulation Sleeving,electrical
5930-01-166-71425190438 INTERCHANGEABLE
Switch,rotary
Naval Sea Systems Command
5305-01-288-6575 INTERCHANGEABLE
Screw,cap,hexagon Head
5306-01-292-99039-086-100534 INTERCHANGEABLE
Bolt,machine
Grove U.s. Llc Dba Grove Us Llc
6680-01-331-19232658 INTERCHANGEABLE
Tachometer Package
Auto Meter Products Inc.
5998-01-391-9747265810-1 INTERCHANGEABLE
Circuit Card Assembly
L3harris Technologies, Inc Div Space & Airborne Systems
Cross-Reference Index
Part NumberManufacturer
2658 Hawker Pacific Aerospace Landing Gear and Components Mfg and Repair (USA)
2658-101 Kaiser Fluid Technologies Inc. (USA)
2658-101 Hawker Pacific Aerospace Landing Gear and Components Mfg and Repair (USA)
103903-1 PRIMARY Rtx Corporation Div Pratt & Whitney (USA)
2658 Kaiser Fluid Technologies Inc. (USA)
Related Parts
5950-00-265-5618INTERCHANGEABLE
COIL,RADIO FREQUENCY
5310-00-268-7519INTERCHANGEABLE
NUT,PLAIN,HEXAGON
2658
5130-00-674-9212INTERCHANGEABLE
BIT,SCREWDRIVER
5325-00-839-9406INTERCHANGEABLE
RECEPTACLE,SPECIAL
2658
5970-00-841-3026INTERCHANGEABLE
INSULATION SLEEVING,ELECTRICAL
5930-01-166-7142INTERCHANGEABLE
SWITCH,ROTARY
5190438
5305-01-288-6575INTERCHANGEABLE
SCREW,CAP,HEXAGON HEAD
5306-01-292-9903INTERCHANGEABLE
BOLT,MACHINE
9-086-100534
6680-01-331-1923INTERCHANGEABLE
TACHOMETER PACKAGE
2658
5998-01-391-9747INTERCHANGEABLE
CIRCUIT CARD ASSEMBLY
265810-1
5136-01-431-6479INTERCHANGEABLE
TAP SET,THREAD CUTTING

Frequently Asked Questions

What is NSN 4820-00-146-1952?

NSN 4820-00-146-1952 is a Valve,regulating,fluid Pressure, manufactured by Rtx Corporation Div Pratt & Whitney, classified under FSC 4820 (No Item Name Available). Status: active.

What are the part numbers for NSN 4820-00-146-1952?

NSN 4820-00-146-1952 has 5 cross-referenced part numbers: 2658 (Hawker Pacific Aerospace Landing Gear and Components Mfg and Repair), 2658-101 (Kaiser Fluid Technologies Inc.), 2658-101 (Hawker Pacific Aerospace Landing Gear and Components Mfg and Repair), 103903-1 (Rtx Corporation Div Pratt & Whitney), 2658 (Kaiser Fluid Technologies Inc.).

What NSN replaces 4820-00-146-1952?

There are 11 known substitutes for 4820-00-146-1952: 5950-00-265-5618, 5310-00-268-7519, 5130-00-674-9212 and 8 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 103903-1?

Key specifications for 103903-1: Second End Seat Angle in Deg: 12.0; First End Seat Angle in Deg: 37.0; Third End Style Designator: GASKET SEAL; Second End Outside Diameter Tube Accommodated: 0.125 INCHES NOMINAL IN. 24 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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