Irwin 1112ZR Straight Flute Tap 4-40 Unc Plug Chamfer

Product Description

The IRWIN 1112ZR is a straight flute tap designed to cut internal threads in through-holes and moderately shallow blind holes. It is ground to a 4-40 UNC thread standard with a plug chamfer, which provides a gradual lead-in of approximately 3 to 5 threads before full cutting begins. The tap features 3 straight flutes and is manufactured from carbon steel with a bright, uncoated finish. The right-hand thread direction and 2B class of fit make it suitable for standard fastener applications requiring moderate tolerance. Machinists, tool and die technicians, and maintenance professionals use this tap for light-duty threading work in steel, aluminum, and similar materials.

This tap is suited for production and maintenance threading operations where 4-40 UNC fastener compatibility is required. The plug chamfer style is the most common general-purpose chamfer, appropriate for both through-holes and blind holes where sufficient thread depth is available. The 2B class of fit indicates a standard commercial tolerance range, which pairs with standard 2A-class bolts and screws. Applications include threading in light fabrication, electrical panel assembly, instrument enclosures, and general machine repair where small-diameter fasteners are common.

Key Features

• 4-40 UNC thread specification for use with standard No. 4 machine screws and bolts
• Plug chamfer with a gradual lead-in for versatile use in through-holes and accessible blind holes
• 3 straight flutes channel chips away during the threading operation
• 2B class of fit meets standard commercial tolerance requirements
• Right-hand thread direction for conventional tapping operations
• Carbon steel construction with bright, uncoated finish for light-duty threading applications

Compatibility

Designed as an OEM-style replacement straight flute tap for applications requiring 4-40 UNC internal threading. No specific compatible model or system information was provided in the product data.

Installation Notes

This tap should be installed in a tap wrench, tapping head, or appropriate machine tool holder. Always power down or disengage the machine before changing tooling. Apply a suitable cutting fluid for the workpiece material to reduce heat and extend tap life. Follow standard machining practices and ensure the tap is aligned perpendicular to the workpiece surface before beginning the threading operation to avoid tap breakage.