PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

31-078Wrench,open End

Armstrong Bros Tool Co · NSN 5120-00-277-1237 · FSC 5120 · No Item Name Available
Verified by PartsTable
NSN 5120-00-277-1237 — this item is cataloged by the U.S. Government under National Stock Number 5120-00-277-1237. Primary manufacturer part number: 31-078.
Features
  • Wrench,open End — FSC 5120
  • Wrenching Surface Shape: OVAL SINGLE END INTERNAL
  • Hardness Rating: 40.0 ROCKWELL C MINIMUM AND 55.0 ROCKWELL C MAXIMUM
  • Head Thickness: 1.250 INCHES NOMINAL IN
  • Nondefinitive Spec/std Data: 5 TYPE
  • Material: STEEL OVERALL
  • Style Designator: SINGLE HEAD
  • Head Angle: 15.0 DEGREES NOMINAL
Applications
  • Applications requiring Steel Overall construction
General Description

The Wrench,open End, cataloged under National Stock Number 5120-00-277-1237, is classified within Federal Supply Class 5120 (No Item Name Available) of the Hand Tools group. The primary manufacturer of record is Armstrong Bros Tool Co. Government technical data includes 8 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 6 commercial cross-references from 6 manufacturers, enabling identification through both NSN and commercial part number lookups. 8 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN5120-00-277-1237
Primary Part Number31-078
Item NameWrench,open End
FSC / FSG5120 / 51 — No Item Name Available
ManufacturerArmstrong Bros Tool Co
StatusCANCELLED
Wrenching Surface ShapeOVAL SINGLE END INTERNAL
Hardness Rating40.0 ROCKWELL C MINIMUM AND 55.0 ROCKWELL C MAXIMUM
Head Thickness1.250 INCHES NOMINAL IN
Nondefinitive Spec/std Data5 TYPE
MaterialSTEEL OVERALL
Style DesignatorSINGLE HEAD
Head Angle15.0 DEGREES NOMINAL
Wrenching Surface Size2.438 INCHES NOMINAL SINGLE END IN
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 8
5325-00-353-2431 INTERCHANGEABLE
Ring,retaining
5120-00-596-158531-078 INTERCHANGEABLE
Tape,fish
Ideal Industries, Inc.
6610-00-703-955331078 INTERCHANGEABLE
Case,machined
Aerosonic Llc
5365-00-788-6889 INTERCHANGEABLE
Spacer,sleeve
2590-01-146-0022 INTERCHANGEABLE
Cap,filler Opening
4140-01-407-043731078 INTERCHANGEABLE
Fan,tubeaxial
Esab Group, Inc., the Dba Esab Welding and Cutting Products Div Esab Welding and Cuttng
4130-01-412-8460638031078 INTERCHANGEABLE
Agitator Arm
Wilshire Corp
5930-01-529-404131078 INTERCHANGEABLE
Switch,thermostatic
Dm Manufacturing, Inc.
Cross-Reference Index
Part NumberManufacturer
31-078 Armstrong Bros Tool Co (USA)
41W1420 Marine Corps (USA)
31-078 Easco Hand Tools Inc Dba Danaher Tool Group Div Danaher Tool Group Easco Hand Tools Inc. (USA)
GGG-W-636 TY5 General Services Administration Federal Supply Service (USA)
31-078 Apex Tool Group, Llc Dba Nicholson (USA)
GGG-W-636 Federal Specifications Promulgated by General Services Administration Washington DC (USA)
Related Parts
5325-00-353-2431INTERCHANGEABLE
RING,RETAINING
5120-00-596-1585INTERCHANGEABLE
TAPE,FISH
31-078
6610-00-703-9553INTERCHANGEABLE
CASE,MACHINED
31078
5365-00-788-6889INTERCHANGEABLE
SPACER,SLEEVE
2590-01-146-0022INTERCHANGEABLE
CAP,FILLER OPENING
4140-01-407-0437INTERCHANGEABLE
FAN,TUBEAXIAL
31078
4130-01-412-8460INTERCHANGEABLE
AGITATOR ARM
638031078
5930-01-529-4041INTERCHANGEABLE
SWITCH,THERMOSTATIC
31078

Frequently Asked Questions

What is NSN 5120-00-277-1237?

NSN 5120-00-277-1237 is a Wrench,open End, manufactured by Armstrong Bros Tool Co, classified under FSC 5120 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 5120-00-277-1237?

NSN 5120-00-277-1237 has 6 cross-referenced part numbers: 31-078 (Armstrong Bros Tool Co), 41W1420 (Marine Corps), 31-078 (Easco Hand Tools Inc Dba Danaher Tool Group Div Danaher Tool Group Easco Hand Tools Inc.), GGG-W-636 TY5 (General Services Administration Federal Supply Service), 31-078 (Apex Tool Group, Llc Dba Nicholson) and 1 more.

What NSN replaces 5120-00-277-1237?

There are 8 known substitutes for 5120-00-277-1237: 5325-00-353-2431, 5120-00-596-1585, 6610-00-703-9553 and 5 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 31-078?

Key specifications for 31-078: Overall Length: 21.750 INCHES NOMINAL IN; Wrenching Surface Shape: OVAL SINGLE END INTERNAL; Hardness Rating: 40.0 ROCKWELL C MINIMUM AND 55.0 ROCKWELL C MAXIMUM; Head Thickness: 1.250 INCHES NOMINAL IN. 9 total characteristics are documented in the Federal Logistics Information System.

Is NSN 5120-00-277-1237 still in active supply?

NSN 5120-00-277-1237 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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