PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

587-551Seat,valve

Steward Machine Co Inc · NSN 4820-00-956-1413 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-00-956-1413 — this item is cataloged by the U.S. Government under National Stock Number 4820-00-956-1413. Primary manufacturer part number: 587-551.
Features
  • Seat,valve — FSC 4820
  • Material: STEEL BODY
  • Seating Surface Shape: ANGULAR
  • Material: COBALT ALLOY FACE
  • Material Document and Classification: MIL-R-17131,TYPE MIL-RCOCR-A MIL SPEC SINGLE MATERIAL RESPONSE FACE
  • Body Outside Diameter: 2.491 INCHES MINIMUM AND 2.492 INCHES MAXIMUM IN
  • Material Document and Classification: 17-4PH,ARMCO STEEL CORP MFR REF SINGLE MATERIAL RESPONSE BODY
  • Body Inside Diameter: 1.557 INCHES MINIMUM AND 1.567 INCHES MAXIMUM IN
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
  • Applications requiring Steel Body construction
General Description

The Seat,valve, cataloged under National Stock Number 4820-00-956-1413, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is Steward Machine Co Inc. Government technical data includes 9 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 6 commercial cross-references from 2 manufacturers, enabling identification through both NSN and commercial part number lookups. 1 verified substitute exists in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN4820-00-956-1413
Primary Part Number587-551
Item NameSeat,valve
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerSteward Machine Co Inc
StatusCANCELLED
MaterialSTEEL BODY
Seating Surface ShapeANGULAR
MaterialCOBALT ALLOY FACE
Material Document and ClassificationMIL-R-17131,TYPE MIL-RCOCR-A MIL SPEC SINGLE MATERIAL RESPONSE FACE
Body Outside Diameter2.491 INCHES MINIMUM AND 2.492 INCHES MAXIMUM IN
Material Document and Classification17-4PH,ARMCO STEEL CORP MFR REF SINGLE MATERIAL RESPONSE BODY
Body Inside Diameter1.557 INCHES MINIMUM AND 1.567 INCHES MAXIMUM IN
Seat Angle in Deg45.000 NOMINAL
Seal Accommodation TypeRECESSED
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 1
3110-00-100-059349520 INTERCHANGEABLE
Cup,tapered Roller Bearing
The Timken Corporation
Cross-Reference Index
Part NumberManufacturer
60-656PC551 Hardie-Tynes Co., Inc. (USA)
60-587PC551 Hardie-Tynes Co., Inc. (USA)
587-551 PRIMARY Steward Machine Co Inc (USA)
587-551 Hardie-Tynes Co., Inc. (USA)
60-606PC551 Hardie-Tynes Co., Inc. (USA)
60-649PC551 Hardie-Tynes Co., Inc. (USA)
Related Parts
3110-00-100-0593INTERCHANGEABLE
CUP,TAPERED ROLLER BEARING
49520

Frequently Asked Questions

What is NSN 4820-00-956-1413?

NSN 4820-00-956-1413 is a Seat,valve, manufactured by Steward Machine Co Inc, classified under FSC 4820 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 4820-00-956-1413?

NSN 4820-00-956-1413 has 6 cross-referenced part numbers: 60-656PC551 (Hardie-Tynes Co., Inc.), 60-587PC551 (Hardie-Tynes Co., Inc.), 587-551 (Steward Machine Co Inc), 587-551 (Hardie-Tynes Co., Inc.), 60-606PC551 (Hardie-Tynes Co., Inc.) and 1 more.

What NSN replaces 4820-00-956-1413?

There is 1 known substitute for 4820-00-956-1413: 3110-00-100-0593. Verify interchangeability with system specifications before substitution.

What are the specifications of 587-551?

Key specifications for 587-551: Material: STEEL BODY; Seating Surface Shape: ANGULAR; Material: COBALT ALLOY FACE; Material Document and Classification: MIL-R-17131,TYPE MIL-RCOCR-A MIL SPEC SINGLE MATERIAL RESPONSE FACE. 9 total characteristics are documented in the Federal Logistics Information System.

Is NSN 4820-00-956-1413 still in active supply?

NSN 4820-00-956-1413 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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