Proto J4912MCF Open End Crowfoot Wrench 1-3/32 in

Product Description

The PROTO J4912MCF is an open end crowfoot wrench designed for metric fastener applications where standard socket or open end wrenches cannot reach. Built to a 1-3/32 inch head diameter and 1/4 inch head thickness, this crowfoot fits onto a standard drive extension or torque wrench to access recessed or obstructed fasteners. The chrome-plated finish resists corrosion and makes cleanup straightforward in shop or field conditions. At an overall length of 1-15/32 inches, it is compact enough for tight-clearance work. Meets ASME B107.21 and Federal Specification GGG-C-1507b, confirming it is built to recognized hand tool standards.

Crowfoot wrenches are a staple in HVAC, plumbing, and mechanical service work where flare nuts, line connections, and recessed fasteners block access to conventional wrenches. This metric-sized crowfoot is suited for technicians working on equipment with metric hardware, including refrigerant line fittings, hydraulic connections, and mechanical assemblies where torque application with a standard drive tool is required. It is typically used by HVAC technicians, pipefitters, and mechanical maintenance professionals.

Key Features

• 1-3/32 inch head diameter sized for metric fastener applications
• 1/4 inch head thickness allows access in shallow or tight clearances
• 1-15/32 inch overall length for compact fitment on drive extensions
• Chrome-plated finish for corrosion resistance and easy cleaning
• Meets ASME B107.21 and Federal Specification GGG-C-1507b standards
• Limited lifetime warranty from the manufacturer

Compatibility

Designed as a standard-drive crowfoot wrench for use with compatible 3/8 inch or 1/2 inch drive extensions and torque wrenches sized to fit the crowfoot shank. Intended for metric fastener service across HVAC, plumbing, and mechanical maintenance applications.

Installation Notes

Crowfoot wrenches are installed by mechanical technicians and service professionals. Always ensure the drive extension is fully seated in the crowfoot before applying torque to prevent slippage or fastener damage. When using with a torque wrench, account for any offset angle between the crowfoot and the drive axis, as this can affect the applied torque value. Disengage all system pressure, power, or fluid supply to the assembly before loosening or tightening fittings.