PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

MS51021-9Setscrew

Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M · NSN 5305-00-045-1684 · FSC 5305 · No Item Name Available
Verified by PartsTable
NSN 5305-00-045-1684 — this item is cataloged by the U.S. Government under National Stock Number 5305-00-045-1684. Primary manufacturer part number: MS51021-9.
Features
  • Setscrew — FSC 5305
  • Thread Class: 3A A
  • Width Across Flats: 0.050 INCHES NOMINAL IN
  • Thread Length: 0.125 INCHES MINIMUM IN
  • Thread Quantity Per Inch: 40
  • Surface Treatment Document and Classification: QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
  • Thread Direction: RIGHT-HAND
  • Head Style: HEADLESS (SETSCREW)
Applications
  • Applications requiring Steel Comp 304 Overall construction
General Description

The Setscrew, cataloged under National Stock Number 5305-00-045-1684, is classified within Federal Supply Class 5305 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M. Government technical data includes 15 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 1 commercial cross-reference from 1 manufacturer, enabling identification through both NSN and commercial part number lookups. 1 verified substitute exists in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5305-00-045-1684
Primary Part NumberMS51021-9
Item NameSetscrew
FSC / FSG5305 / 53 — No Item Name Available
ManufacturerMilitary Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
StatusACTIVE
Thread Class3A A
Width Across Flats0.050 INCHES NOMINAL IN
Thread Length0.125 INCHES MINIMUM IN
Thread Quantity Per Inch40
Surface Treatment Document and ClassificationQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
Thread DirectionRIGHT-HAND
Head StyleHEADLESS (SETSCREW)
Hardness Rating25.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM OVERALL
Thread Series DesignatorUNIFIED NATIONAL COARSE (UNC)
Internal Drive StyleHEXAGON
MaterialSTEEL COMP 304 OVERALL
Point StyleCUP
Surface TreatmentPASSIVATE OVERALL
Nominal Thread Diameter0.112 INCHES IN
Fastener Length0.125 INCHES NOMINAL IN
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 1
5305-00-800-7261MS51021-9 INTERCHANGEABLE
Setscrew
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
Cross-Reference Index
Part NumberManufacturer
MS51021-9 Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
Related Parts
5305-00-800-7261INTERCHANGEABLE
SETSCREW
MS51021-9

Frequently Asked Questions

What is NSN 5305-00-045-1684?

NSN 5305-00-045-1684 is a Setscrew, manufactured by Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M, classified under FSC 5305 (No Item Name Available). Status: active.

What are the part numbers for NSN 5305-00-045-1684?

NSN 5305-00-045-1684 has 1 cross-referenced part number: MS51021-9 (Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M).

What NSN replaces 5305-00-045-1684?

There is 1 known substitute for 5305-00-045-1684: 5305-00-800-7261. Verify interchangeability with system specifications before substitution.

What are the specifications of MS51021-9?

Key specifications for MS51021-9: Thread Class: 3A A; Width Across Flats: 0.050 INCHES NOMINAL IN; Thread Length: 0.125 INCHES MINIMUM IN; Thread Quantity Per Inch: 40. 15 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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