PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

H39991-6Nut,self-Locking,extended Washer

Howmet Global Fastening Systems Inc · NSN 5310-00-168-7302 · FSC 5310 · No Item Name Available
Verified by PartsTable
NSN 5310-00-168-7302 — this item is cataloged by the U.S. Government under National Stock Number 5310-00-168-7302. Primary manufacturer part number: H39991-6.
Features
  • Nut,self-Locking,extended Washer — FSC 5310
  • Material Document and Classification: AMS 6370 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
  • Nominal Thread Size: 0.375 INCHES IN
  • Thread Series: UNIFIED NATIONAL JOINT FINE (UNJF)
  • Hardness Rating: 38.0 ROCKWELL C MINIMUM AND 44.0 ROCKWELL C MAXIMUM
  • Thread Quantity Per Inch: 24
  • Surface Treatment: CADMIUM OVERALL
  • Width Across Flats: 0.430 INCHES MINIMUM AND 0.439 INCHES MAXIMUM IN
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
  • Applications requiring Steel Comp 4130 Overall construction
General Description

The Nut,self-Locking,extended Washer, cataloged under National Stock Number 5310-00-168-7302, is classified within Federal Supply Class 5310 (No Item Name Available) of the Hardware and Abrasives group. The primary manufacturer of record is Howmet Global Fastening Systems Inc. Government technical data includes 15 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 5 commercial cross-references from 4 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
NSN5310-00-168-7302
Primary Part NumberH39991-6
Item NameNut,self-Locking,extended Washer
FSC / FSG5310 / 53 — No Item Name Available
ManufacturerHowmet Global Fastening Systems Inc
StatusACTIVE
Material Document and ClassificationAMS 6370 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
Nominal Thread Size0.375 INCHES IN
Thread SeriesUNIFIED NATIONAL JOINT FINE (UNJF)
Hardness Rating38.0 ROCKWELL C MINIMUM AND 44.0 ROCKWELL C MAXIMUM
Thread Quantity Per Inch24
Surface TreatmentCADMIUM OVERALL
Width Across Flats0.430 INCHES MINIMUM AND 0.439 INCHES MAXIMUM IN
Washer Outside Diameter0.598 INCHES MAXIMUM IN
Thread DirectionRIGHT-HAND
Thread Class3B
Nut StyleHEXAGON
Washer Thickness0.060 INCHES NOMINAL IN
MaterialSTEEL COMP 4130 OVERALL
Surface Treatment Document and ClassificationAMS 2400 ASSN STD SINGLE TREATMENT RESPONSE OVERALL
Locking FeaturePREVAILING TORQUE ALL METAL DESIGN
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 2
5950-00-764-2514H166 INTERCHANGEABLE
Reactor
Magnetika Inc
5950-00-789-941527C54 INTERCHANGEABLE
Reactor
Thordarson Inc
Cross-Reference Index
Part NumberManufacturer
H16-6 Leonardo Spa Helicopters Division - Production Site (ITA)
5310PL2026292 Jednolity Indeks Materialowy - Uniform Material Index (POL)
H39991-6 PRIMARY Howmet Global Fastening Systems Inc (USA)
672268 Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney (USA)
H16-6 Howmet Global Fastening Systems Inc (USA)
Related Parts
5950-00-764-2514INTERCHANGEABLE
REACTOR
H166
5950-00-789-9415INTERCHANGEABLE
REACTOR
27C54

Frequently Asked Questions

What is NSN 5310-00-168-7302?

NSN 5310-00-168-7302 is a Nut,self-Locking,extended Washer, manufactured by Howmet Global Fastening Systems Inc, classified under FSC 5310 (No Item Name Available). Status: active.

What are the part numbers for NSN 5310-00-168-7302?

NSN 5310-00-168-7302 has 5 cross-referenced part numbers: H16-6 (Leonardo Spa Helicopters Division - Production Site), 5310PL2026292 (Jednolity Indeks Materialowy - Uniform Material Index), H39991-6 (Howmet Global Fastening Systems Inc), 672268 (Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney), H16-6 (Howmet Global Fastening Systems Inc).

What NSN replaces 5310-00-168-7302?

There are 2 known substitutes for 5310-00-168-7302: 5950-00-764-2514, 5950-00-789-9415. Verify interchangeability with system specifications before substitution.

What are the specifications of H39991-6?

Key specifications for H39991-6: Material Document and Classification: AMS 6370 ASSN STD SINGLE MATERIAL RESPONSE OVERALL; Nominal Thread Size: 0.375 INCHES IN; Thread Series: UNIFIED NATIONAL JOINT FINE (UNJF); Hardness Rating: 38.0 ROCKWELL C MINIMUM AND 44.0 ROCKWELL C MAXIMUM. 16 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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