Kennametal 1544769 Hand Tap 7/8-9 Unc Bottoming Tin Hss

Product Description

The KENNAMETAL 1544769 is a 7/8-9 UNC bottoming hand tap manufactured from high-speed steel with a titanium nitride (TiN) coating. It is designed to cut full threads to the bottom of a blind hole, making it the correct choice when thread depth must be maximized in a stopped bore. The tap features a 4-flute straight-flute geometry, a right-hand thread direction, and a Class 3B fit with an H4 thread limit. Overall length is 4.69 inches with a thread length of 2.219 inches. Machinists and maintenance technicians use this tool in manual tapping operations with a tap wrench or tapping fixture.

This tap is suited for threading blind holes in cast iron, stainless steel, and carbon steel workpieces where a bottoming chamfer is required to bring threads as close as possible to the bottom of the bore. It is appropriate for production and maintenance applications in industrial shops, tool rooms, and field repair settings. The straight-flute design keeps chips manageable in through-hole applications and short blind bores. The TiN coating extends tool life by reducing friction and increasing surface hardness compared to uncoated HSS.

Key Features

• Bottoming chamfer produces full threads to the bottom of blind holes
• High-speed steel construction withstands the heat generated in manual tapping
• Titanium nitride (TiN) coating reduces friction and extends tool life
• 4-flute straight-flute geometry for controlled chip formation
• Class 3B fit with H4 thread limit ensures consistent thread tolerance
• Right-hand, 7/8-9 UNC thread form for standard inch fastener applications

Compatibility

Rated for use in cast iron, stainless steel, and steel workpieces. Designed as a standard OEM-style hand tap for 7/8-9 UNC bottoming thread applications.

Installation Notes

This tap is installed by a machinist or skilled technician using a tap wrench sized for the 0.697-inch shank diameter. Always secure the workpiece and align the tap perpendicular to the bore before applying torque. Use an appropriate cutting fluid for the material being tapped, particularly when working with stainless steel. Back the tap off periodically to break and clear chips, and never force the tap if resistance increases unexpectedly.