PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

FFB561Screw,lag

Federal Specifications Promulgated by General Services Administration Washington DC · NSN 5305-00-177-5624 · FSC 5305 · No Item Name Available
Verified by PartsTable
NSN 5305-00-177-5624 — this item is cataloged by the U.S. Government under National Stock Number 5305-00-177-5624. Primary manufacturer part number: FFB561.
Features
  • Screw,lag — FSC 5305
  • Shoulder Length: 0.312 INCHES MINIMUM FIRST SHOULDER IN
  • Head Style: HEXAGON
  • Hardness Rating: 60.0 ROCKWELL B MINIMUM OVERALL
  • Nondefinitive Spec/std Data: 1 TYPE AND 1 STYLE AND B GRADE
  • Head Height: 0.378 INCHES MINIMUM AND 0.444 INCHES MAXIMUM IN
  • Nonmachine Nominal Thread Diameter: 0.625 INCHES IN
  • Width Between Flats: 0.906 INCHES MINIMUM AND 0.937 INCHES MAXIMUM IN
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
  • Applications requiring Steel Overall construction
General Description

The Screw,lag, cataloged under National Stock Number 5305-00-177-5624, is classified within Federal Supply Class 5305 (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 16 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 3 commercial cross-references from 2 manufacturers, enabling identification through both NSN and commercial part number lookups. 3 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN5305-00-177-5624
Primary Part NumberFFB561
Item NameScrew,lag
FSC / FSG5305 / 53 — No Item Name Available
ManufacturerFederal Specifications Promulgated by General Services Administration Washington DC
StatusCANCELLED
Shoulder Length0.312 INCHES MINIMUM FIRST SHOULDER IN
Head StyleHEXAGON
Hardness Rating60.0 ROCKWELL B MINIMUM OVERALL
Nondefinitive Spec/std Data1 TYPE AND 1 STYLE AND B GRADE
Head Height0.378 INCHES MINIMUM AND 0.444 INCHES MAXIMUM IN
Nonmachine Nominal Thread Diameter0.625 INCHES IN
Width Between Flats0.906 INCHES MINIMUM AND 0.937 INCHES MAXIMUM IN
Surface TreatmentZINC OVERALL
Fastener Length5.000 INCHES NOMINAL IN
Nonmachine Thread StyleGIMLET POINT (TYPE A, AB OR BA)
Surface Treatment Document and ClassificationASTM A153-60 ASSN STD SINGLE TREATMENT RESPONSE OVERALL
Shoulder ShapeROUND FIRST SHOULDER
MaterialSTEEL OVERALL
Minimum Tensile Strength55000 POUNDS PER SQUARE INCH LBS
Shoulder Diameter0.605 INCHES MINIMUM AND 0.642 INCHES MAXIMUM FIRST SHOULDER IN
Material Document and ClassificationFF-B-561,GRADE B FED SPEC SINGLE MATERIAL RESPONSE OVERALL
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 3
5305-00-406-5199 INTERCHANGEABLE
Screw,lag
5305-00-407-6543 INTERCHANGEABLE
Screw,lag
5305-00-449-2240 INTERCHANGEABLE
Screw,lag
Cross-Reference Index
Part NumberManufacturer
FFB561 Federal Specifications Promulgated by General Services Administration Washington DC (USA)
MS16992-606 Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
FF-B-561D Federal Specifications Promulgated by General Services Administration Washington DC (USA)
Related Parts
5305-00-406-5199INTERCHANGEABLE
SCREW,LAG
5305-00-407-6543INTERCHANGEABLE
SCREW,LAG
5305-00-449-2240INTERCHANGEABLE
SCREW,LAG

Frequently Asked Questions

What is NSN 5305-00-177-5624?

NSN 5305-00-177-5624 is a Screw,lag, manufactured by Federal Specifications Promulgated by General Services Administration Washington DC, classified under FSC 5305 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 5305-00-177-5624?

NSN 5305-00-177-5624 has 3 cross-referenced part numbers: FFB561 (Federal Specifications Promulgated by General Services Administration Washington DC), MS16992-606 (Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M), FF-B-561D (Federal Specifications Promulgated by General Services Administration Washington DC).

What NSN replaces 5305-00-177-5624?

There are 3 known substitutes for 5305-00-177-5624: 5305-00-406-5199, 5305-00-407-6543, 5305-00-449-2240. Verify interchangeability with system specifications before substitution.

What are the specifications of FFB561?

Key specifications for FFB561: Shoulder Length: 0.312 INCHES MINIMUM FIRST SHOULDER IN; Head Style: HEXAGON; Hardness Rating: 60.0 ROCKWELL B MINIMUM OVERALL; Nondefinitive Spec/std Data: 1 TYPE AND 1 STYLE AND B GRADE. 16 total characteristics are documented in the Federal Logistics Information System.

Is NSN 5305-00-177-5624 still in active supply?

NSN 5305-00-177-5624 is currently cancelled. Check with the Defense Logistics Agency for current availability and authorized substitutes.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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