Kennametal 4131396 Hand Tap 7/8-9 Unc Plug 4-flute Hss

Product Description

The KENNAMETAL 4131396 is a 7/8-9 UNC straight-flute hand tap designed for cutting internal threads in ferrous and cast materials. Built from high-speed steel with an oxide finish, it produces accurate 3B-class threads in through-hole and blind-hole applications. The plug chamfer provides 3 to 5 leading threads for easy starting and controlled cutting engagement. With 4 flutes and an H4 thread limit, this tap holds tight tolerance control across production and maintenance threading operations. At 4-11/16 inches overall length and a 2-7/32 inch thread length, it fits standard tap wrenches and machine setups. Machinists, tool-and-die workers, and maintenance technicians are the primary users.

This tap is suited for threading operations in cast iron, ductile iron, and steel. It works in manual hand-tapping with a tap wrench as well as low-speed machine tapping where coolant-through tooling is not required. The plug chamfer makes it the right choice when starting a thread from the top of a hole where some lead-in length is acceptable. It is part of the KENNAMETAL Series 5303-S and is sized for common 7/8-9 UNC fastener applications found in heavy equipment maintenance, structural fabrication, and general machining environments.

Key Features

• 7/8-9 UNC thread form with right-hand cutting direction and 3B class of fit
• High-speed steel construction provides durability across ferrous materials including cast iron and steel
• Oxide finish improves lubrication retention and reduces galling during hand tapping
• Plug chamfer with H4 thread limit delivers consistent tolerance control and reliable thread engagement
• 4-flute straight-flute geometry supports chip clearance in through-hole and shallow blind-hole applications
• 2-7/32 inch thread length accommodates workpiece thicknesses common in structural and maintenance threading

Compatibility

Designed for threading cast iron, ductile iron, and steel workpieces requiring 7/8-9 UNC internal threads to a 3B class of fit. Compatible with standard tap wrenches and manual or low-speed machine tapping setups that accept the 0.697-inch shank diameter.

Installation Notes

This tap is installed and operated by machinists or maintenance technicians using a properly sized tap wrench or tapping head. Secure the workpiece firmly before beginning; misalignment between the tap and hole axis is the leading cause of tap breakage. Apply a suitable cutting fluid rated for the workpiece material before and during tapping to reduce heat and extend tool life. Do not force the tap if resistance increases suddenly — back off to break chips before continuing.