Head Height: 11.7 MILLIMETERS MINIMUM AND 12.0 MILLIMETERS MAXIMUM MM
External Thread Tolerance Class: 4G6G
Fastener Length: 50.0 MILLIMETERS NOMINAL MM
Thread Pitch in Millimeters: 1.75
Thread Length: 36.0 MILLIMETERS MINIMUM AND 44.8 MILLIMETERS MAXIMUM MM
Nominal Thread Diameter: 12.0 MILLIMETERS MM
Identification
NSN: 5305-01-646-1663
NIIN: 016461663
FSC: 5305 — Screws
FSG: 53 — Hardware and Abrasives
General Description
The Screw,cap,socket Head, cataloged under National Stock Number 5305-01-646-1663, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. Government technical data includes 14 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 7 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
Technical Specifications
Parameter
Value
NSN
5305-01-646-1663
Item Name
Screw,cap,socket Head
FSC / FSG
5305 / 53 — Screws
Status
ACTIVE
Width Across Flats
10.0 MILLIMETERS NOMINAL MM
Head Height
11.7 MILLIMETERS MINIMUM AND 12.0 MILLIMETERS MAXIMUM MM
External Thread Tolerance Class
4G6G
Fastener Length
50.0 MILLIMETERS NOMINAL MM
Thread Pitch in Millimeters
1.75
Thread Length
36.0 MILLIMETERS MINIMUM AND 44.8 MILLIMETERS MAXIMUM MM
Nominal Thread Diameter
12.0 MILLIMETERS MM
Head Style
FLAT CHAMFER
Thread Direction
RIGHT-HAND
Locking Feature
PELLET OR STRIP OR PATCH THREADS
Internal Drive Style
HEXAGON
Material
STEEL PROPERTY CLASS 12.9 OVERALL
Thread Series Designator
ISO M
Head Diameter
17.6 MILLIMETERS MINIMUM AND 18.0 MILLIMETERS MAXIMUM MM
Lifecycle & Compliance
Acquisition Status
ACTIVE
DEMIL Code
DEMIL A — No Demilitarization Required
Hazard
No hazard code in the DLA record (HMIC N)
Criticality Code
X
⇄Related Items7
Each row states its source: a government interchangeability/replacement code, or a possible match on a shared part number.
NSN 5305-01-646-1663 is a Screw,cap,socket Head, classified under FSC 5305, Screws. Status: active.
What NSN replaces 5305-01-646-1663?
7 possible matches (shared part number, not a government interchangeability claim): 5305-01-646-1677, 5305-01-646-1686, 5305-01-646-1699. Verify interchangeability with system specifications before substitution.
What are the specifications of 5305-01-646-1663?
Key specifications for 5305-01-646-1663: Width Across Flats: 10.0 MILLIMETERS NOMINAL MM; Head Height: 11.7 MILLIMETERS MINIMUM AND 12.0 MILLIMETERS MAXIMUM MM; External Thread Tolerance Class: 4G6G; Fastener Length: 50.0 MILLIMETERS NOMINAL MM. 14 specifications are documented in the U.S. Government catalog.
Is NSN 5305-01-646-1663 hazardous material?
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
Sources
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
✓ Data cited from the U.S. Government catalog; commercial cross-references from OEM and certified industry sources.