PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

128321Bolt,square Neck

General Motors Llc Dba General Motors Llc · NSN 5306-00-012-8321 · FSC 5306 · No Item Name Available
Verified by PartsTable
NSN 5306-00-012-8321 — this item is cataloged by the U.S. Government under National Stock Number 5306-00-012-8321. Primary manufacturer part number: 128321.
Features
  • Bolt,square Neck — FSC 5306
  • Thread Series Designator: UNIFIED NATIONAL COARSE (UNC)
  • Material Document and Classification: QQ-S-633,CANC FED SPEC SINGLE MATERIAL RESPONSE OVERALL
  • Thread Class: 2A A
  • Thread Length: 0.625 INCHES MINIMUM IN
  • Neck Width: 0.185 INCHES MINIMUM AND 0.199 INCHES MAXIMUM IN
  • Thread Quantity Per Inch: 24
  • Head Diameter: 0.625 INCHES NOMINAL IN
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
  • Applications requiring Steel Overall construction
General Description

The Bolt,square Neck, cataloged under National Stock Number 5306-00-012-8321, is classified within Federal Supply Class 5306 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is General Motors Llc Dba General Motors Llc. Government technical data includes 14 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 2 commercial cross-references from 2 manufacturers, enabling identification through both NSN and commercial part number lookups. 2 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5306-00-012-8321
Primary Part Number128321
Item NameBolt,square Neck
FSC / FSG5306 / 53 — No Item Name Available
ManufacturerGeneral Motors Llc Dba General Motors Llc
StatusACTIVE
Thread Series DesignatorUNIFIED NATIONAL COARSE (UNC)
Material Document and ClassificationQQ-S-633,CANC FED SPEC SINGLE MATERIAL RESPONSE OVERALL
Thread Class2A A
Thread Length0.625 INCHES MINIMUM IN
Neck Width0.185 INCHES MINIMUM AND 0.199 INCHES MAXIMUM IN
Thread Quantity Per Inch24
Head Diameter0.625 INCHES NOMINAL IN
Nominal Thread Diameter0.190 INCHES IN
Thread DirectionRIGHT-HAND
Fastener Length0.875 INCHES NOMINAL IN
Head Height0.094 INCHES NOMINAL IN
MaterialSTEEL OVERALL
Head StyleOVAL
Neck Length0.094 INCHES MINIMUM AND 0.125 INCHES MAXIMUM IN
Lifecycle & Compliance
Acquisition StatusACTIVE
Successor5340-01-468-0724 (128321)
HAZMATNo
Verified Substitutes 2
5340-01-468-0724128321 SUCCESSOR
Plate,mounting
Jered Llc
5935-00-234-2116 INTERCHANGEABLE
Jack,telephone
Cross-Reference Index
Part NumberManufacturer
128321 General Motors Corp (USA)
128321 PRIMARY General Motors Llc Dba General Motors Llc (USA)
Related Parts
SUCCESSOR 5340-01-468-0724 Plate,mounting · 128321
5935-00-234-2116INTERCHANGEABLE
JACK,TELEPHONE

Frequently Asked Questions

What is NSN 5306-00-012-8321?

NSN 5306-00-012-8321 is a Bolt,square Neck, manufactured by General Motors Llc Dba General Motors Llc, classified under FSC 5306 (No Item Name Available). Status: active.

What are the part numbers for NSN 5306-00-012-8321?

NSN 5306-00-012-8321 has 2 cross-referenced part numbers: 128321 (General Motors Corp), 128321 (General Motors Llc Dba General Motors Llc).

What NSN replaces 5306-00-012-8321?

There are 2 known substitutes for 5306-00-012-8321: 5340-01-468-0724, 5935-00-234-2116. Verify interchangeability with system specifications before substitution.

What are the specifications of 128321?

Key specifications for 128321: Thread Series Designator: UNIFIED NATIONAL COARSE (UNC); Material Document and Classification: QQ-S-633,CANC FED SPEC SINGLE MATERIAL RESPONSE OVERALL; Thread Class: 2A A; Thread Length: 0.625 INCHES MINIMUM IN. 14 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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