PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

FFB571TYPEC2CLASSCBolt,square Neck

Federal Specifications Promulgated by General Services Administration Washington DC · NSN 5306-00-208-2091 · FSC 5306 · No Item Name Available
Verified by PartsTable
NSN 5306-00-208-2091 — this item is cataloged by the U.S. Government under National Stock Number 5306-00-208-2091. Primary manufacturer part number: FFB571TYPEC2CLASSC.
Features
  • Bolt,square Neck — FSC 5306
  • Thread Class: 2A A
  • Thread Length: 0.750 INCHES MINIMUM IN
  • Thread Quantity Per Inch: 20
  • Neck Length: 0.219 INCHES NOMINAL IN
  • Material: STEEL OVERALL
  • Nondefinitive Spec/std Data: C2 TYPE
  • Surface Treatment Document and Classification: QQ-P-416 FED SPEC 1ST TREATMENT RESPONSE OR QQ-Z-325 FED SPEC 2ND TREATMENT RESPONSE OVERALL
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 5306-00-208-2091, is classified within Federal Supply Class 5306 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is Federal Specifications Promulgated by General Services Administration Washington DC. Government technical data includes 18 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 2 commercial cross-references from 1 manufacturer, enabling identification through both NSN and commercial part number lookups. 3 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5306-00-208-2091
Primary Part NumberFFB571TYPEC2CLASSC
Item NameBolt,square Neck
FSC / FSG5306 / 53 — No Item Name Available
ManufacturerFederal Specifications Promulgated by General Services Administration Washington DC
StatusACTIVE
Thread Class2A A
Thread Length0.750 INCHES MINIMUM IN
Thread Quantity Per Inch20
Neck Length0.219 INCHES NOMINAL IN
MaterialSTEEL OVERALL
Nondefinitive Spec/std DataC2 TYPE
Surface Treatment Document and ClassificationQQ-P-416 FED SPEC 1ST TREATMENT RESPONSE OR QQ-Z-325 FED SPEC 2ND TREATMENT RESPONSE OVERALL
Material Document and ClassificationFF-B-571 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
Thread Series DesignatorUNIFIED NATIONAL COARSE (UNC)
Head StyleBUTTON
Thread DirectionRIGHT-HAND
Features ProvidedSQUARE NUT
Nominal Thread Diameter0.250 INCHES IN
Fastener Length3.500 INCHES NOMINAL IN
Head Diameter0.563 INCHES NOMINAL IN
Head Height0.125 INCHES NOMINAL IN
Surface TreatmentCADMIUM OR ZINC OVERALL
Neck Width0.250 INCHES NOMINAL IN
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 3
Bolt,machine
5306-00-639-3314FFB571TYPEC2CLASSC INTERCHANGEABLE
Bolt,square Neck
General Services Administration Federal Supply Service
5306-00-993-6257MS35751-77 INTERCHANGEABLE
Bolt,square Neck
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
Cross-Reference Index
Part NumberManufacturer
FFB571TYPEC2CLASSC Federal Specifications Promulgated by General Services Administration Washington DC (USA)
FFB571 Federal Specifications Promulgated by General Services Administration Washington DC (USA)
Related Parts
5306-00-582-5952SUCCESSOR
BOLT,MACHINE
5306-00-639-3314INTERCHANGEABLE
BOLT,SQUARE NECK
FFB571TYPEC2CLASSC
5306-00-993-6257INTERCHANGEABLE
BOLT,SQUARE NECK
MS35751-77

Frequently Asked Questions

What is NSN 5306-00-208-2091?

NSN 5306-00-208-2091 is a Bolt,square Neck, manufactured by Federal Specifications Promulgated by General Services Administration Washington DC, classified under FSC 5306 (No Item Name Available). Status: active.

What are the part numbers for NSN 5306-00-208-2091?

NSN 5306-00-208-2091 has 2 cross-referenced part numbers: FFB571TYPEC2CLASSC (Federal Specifications Promulgated by General Services Administration Washington DC), FFB571 (Federal Specifications Promulgated by General Services Administration Washington DC).

What NSN replaces 5306-00-208-2091?

There are 3 known substitutes for 5306-00-208-2091: 5306-00-582-5952, 5306-00-639-3314, 5306-00-993-6257. Verify interchangeability with system specifications before substitution.

What are the specifications of FFB571TYPEC2CLASSC?

Key specifications for FFB571TYPEC2CLASSC: Thread Class: 2A A; Thread Length: 0.750 INCHES MINIMUM IN; Thread Quantity Per Inch: 20; Neck Length: 0.219 INCHES NOMINAL IN. 18 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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