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21643A1 — SEAT,VALVE

✓ Government record, cited
— · GATE VALVE
PRODUCT OVERVIEW

21643A1: SEAT,VALVE.

The SEAT,VALVE is a the manufacturer industrial component. Key specifications include material: STEEL CORROSION RESISTING OVERALL, overall_height: 0.084 INCHES NOMINAL IN, style_designator: PLAIN, seat_angle_in_deg: 45.000 NOMINAL, body_inside_diameter: 0.325 INCHES NOMINAL IN, body_outside_diameter: 0.543 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 4820-00-085-3977, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
21643A1
NSN: 4820-00-085-3977
FSC: 4820 — Valves, Nonpowered
CAGE: 73475 — SCHNEIDER ELECTRIC SYSTEMS USA INC (USA)
SPECIFICATIONS
materialSTEEL CORROSION RESISTING OVERALL
overall_height0.084 INCHES NOMINAL IN
style_designatorPLAIN
seat_angle_in_deg45.000 NOMINAL
body_inside_diameter0.325 INCHES NOMINAL IN
body_outside_diameter0.543 INCHES NOMINAL IN
seating_surface_shapeANGULAR
NSN4820-00-085-3977
COMPONENT DIAGRAM
GATE VALVE — FULL OPEN OR FULL CLOSE ONLY Rising STEM BONNET FLOW → → FLOW SEATS — — SIZE: — · — · — PN: 21643A1 · OEM ⚠ VERIFY BEFORE ORDERING Gate valves = FULL OPEN or FULL CLOSE only — never throttle. Partial opening causes seat erosion and vibration. ✓ BROKER TIP Rising stem shows valve position visually — easier maintenance. Non-rising stem saves headroom. PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
BODY OUTSIDE DIAMETER: 0.543 INCHES NOMINAL IN
•
STYLE DESIGNATOR: PLAIN
•
BODY INSIDE DIAMETER: 0.325 INCHES NOMINAL IN
•
MATERIAL: STEEL CORROSION RESISTING OVERALL
•
SEAT ANGLE IN DEG: 45.000 NOMINAL
•
SEATING SURFACE SHAPE: ANGULAR
TECHNICAL CHARACTERISTICS
OVERALL HEIGHT0.084 INCHES NOMINAL IN
BODY OUTSIDE DIAMETER0.543 INCHES NOMINAL IN
STYLE DESIGNATORPLAIN
BODY INSIDE DIAMETER0.325 INCHES NOMINAL IN
MATERIALSTEEL CORROSION RESISTING OVERALL
SEAT ANGLE IN DEG45.000 NOMINAL
SEATING SURFACE SHAPEANGULAR
OTHER ITEMS IN FSC 4820 — Valves, Nonpowered
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
4820-00-000-0097 4820-00-001-0010 4820-00-001-0020 4820-00-001-0021 4820-00-001-0032 4820-00-001-0037 4820-00-001-0042 4820-00-001-1230
SUBSTITUTES & CROSS-REFERENCES

No substitute or cross-reference records for this part.

LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 21643A1?
21643A1 is a SEAT,VALVE.
What is the NSN for 21643A1?
21643A1 is cataloged in the U.S. Government catalog under NSN 4820-00-085-3977. This indicates validated use in U.S. government and defense supply chains.
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✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.