Hertel K008649AS 1-1/8-7 Unc Straight Flute Tap Hss

Product Description

The HERTEL K008649AS is a straight flute tap designed for cutting 1-1/8-7 UNC internal threads in a variety of materials. Built from high speed steel (HSS) with a bright, uncoated finish, this tap handles threading operations in ferrous and non-ferrous metals where a standard surface treatment is appropriate. It features a plug chamfer, which starts the thread with a moderate lead-in, making it suitable for through-hole and deeper blind-hole applications. With 4 flutes and an H4 thread limit, it holds consistent tolerances for a Class 3B thread fit. Overall length is 5-7/16 inches and the tool weighs approximately 0.85 pounds. Installed with a right-hand threading direction, it is intended for use in manual or CNC tapping operations by machinists and maintenance professionals.

This tap is used in machining, manufacturing, and industrial maintenance environments where 1-1/8-7 UNC threads are required. The plug chamfer style makes it a general-purpose choice for threading operations in through holes or holes with sufficient depth for the chamfer lead-in. It is appropriate for use in machine shops, fabrication facilities, and field maintenance settings where a durable HSS tap in a large-diameter, coarse-pitch UNC thread is needed. The bright finish makes it a cost-effective option when specialized coatings are not required by the workpiece material or cutting conditions.

Key Features

• 1-1/8-7 UNC thread size, coarse pitch for high-strength fastener applications
• High speed steel construction provides good wear resistance across a range of work materials
• Plug chamfer with 4-5 thread lead-in suits both through-hole and deeper blind-hole threading
• 4 straight flutes for efficient chip clearance in standard tapping operations
• H4 thread limit and Class 3B fit for consistent, close-tolerance thread production
• Right-hand cut, bright uncoated finish, no coolant-through requirement

Compatibility

Designed for use in any application requiring a 1-1/8-7 UNC Class 3B internal thread. Compatible with standard tap holders and tapping heads sized for large-diameter taps in manual or CNC machine setups.

Installation Notes

This tap should be installed by a qualified machinist familiar with large-diameter tapping operations. Ensure the workpiece is securely fixtured and properly drilled to the correct tap drill diameter before threading begins. Use an appropriate cutting fluid for the workpiece material to extend tap life and improve thread quality. Follow machine manufacturer guidelines and applicable shop safety procedures when operating tapping equipment.