Kennametal 4131388 Hand Tap 3/4-10 Unc Plug 4-flute Hss

Product Description

The KENNAMETAL 4131388 is a 3/4-10 UNC straight-flute hand tap designed for cutting right-hand internal threads in ferrous materials. Built from high-speed steel with an oxide finish, it offers solid wear resistance for production and maintenance threading applications. The plug chamfer — 3 to 5 threads of lead — makes this tap suitable for through-holes and blind holes with adequate clearance. With 4 flutes and an H3 thread limit, it produces threads at the upper tolerance range, accounting for slight spring-back in tougher alloys. Machinists and millwrights use this tap with a standard tap wrench or tapping fixture.

This tap is suited for threading cast iron, ductile iron, and steel workpieces in both job-shop and production environments. The 3/4-10 UNC thread form is a coarse-pitch standard widely used in structural fastening, heavy equipment, and tooling assemblies. The straight-flute design keeps chips local to the cutting zone, making it most effective when paired with cutting fluid and used in through-hole applications where chips can be periodically cleared. It is well matched for hand tapping operations where controlled feed and feel are required.

Key Features

• 3/4-10 UNC right-hand thread form with plug chamfer for through-hole and open blind-hole use
• H3 thread limit for upper-tolerance fits, compensating for material spring-back in steel and iron
• High-speed steel construction provides toughness across cast iron, ductile iron, and steel
• Oxide surface finish reduces friction and improves chip flow during hand tapping
• 4-flute straight-flute geometry for balanced cutting and chip clearance with cutting fluid
• No coolant-through requirement — suited for hand or low-speed machine tapping setups

Compatibility

Designed for cutting 3/4-10 UNC right-hand internal threads in cast iron, ductile iron, and steel. Compatible with standard 3/4-inch square-drive tap wrenches and tapping heads that accept the 0.59-inch shank diameter.

Installation Notes

Installation should be performed by a machinist or qualified tradesperson familiar with thread-cutting operations. Secure the workpiece fully before tapping and apply a suitable cutting fluid for the material being threaded — this extends tool life and improves thread quality. Keep the tap aligned perpendicular to the workpiece surface throughout the operation to avoid thread lead error or tap breakage. Back the tap off periodically to break and clear chips, especially in blind-hole applications.