Balax 18665-010 Thread Forming Sti Tap M8x1.25 Bottoming Hss

Product Description

The BALAX 18665-010 is a thread forming STI tap designed for cutting M8 x 1.25 metric coarse internal threads in spark-eroded or damaged thread inserts. Unlike cutting taps, this forming tap displaces material rather than removing chips, producing stronger threads with a superior surface finish. It is made from high-speed steel with a bright uncoated finish and features a bottoming chamfer for threading close to the bottom of blind holes. The D5 thread limit designation suits standard tolerance fits. Overall length is 2-15/16 inches with a 1-1/4 inch thread length, making it suitable for shallow-to-medium depth applications in machine shop and maintenance environments.

This tap is used in applications requiring STI (Screw Thread Insert) preparation, where a HeliCoil or similar wire thread insert is installed after tapping to restore or reinforce a threaded hole. The bottoming chamfer design allows threading to within a few threads of the bottom of a blind hole. Typical install scenarios include engine component repair, aerospace maintenance, and precision machining where metric coarse thread inserts are specified. Machinists and maintenance technicians working with M8 x 1.25 insert systems will find this tap compatible with the BXMSTI series workflow.

Key Features

• Thread forming design displaces material rather than cutting chips, producing stronger thread walls
• Bottoming chamfer allows threading to the bottom of blind holes
• M8 x 1.25 metric coarse thread size with D5 thread limit for standard tolerance fits
• High-speed steel construction provides wear resistance across a range of workpiece materials
• Bright uncoated finish suitable for use with cutting fluids and general-purpose applications
• Part of the BXMSTI series for consistent STI tap sizing and compatibility

Compatibility

Designed for use in M8 x 1.25 metric coarse STI thread insert applications as part of the BALAX BXMSTI series.

Installation Notes

This tap should be installed and operated by qualified machinists or maintenance technicians familiar with thread forming processes. Always secure the workpiece and use appropriate cutting fluid before tapping to reduce friction and extend tool life. Ensure correct drill size for thread forming applications, as forming taps require a larger pilot hole than cutting taps for the same thread size. Do not apply excessive torque - thread forming requires controlled, steady feed pressure to avoid tap breakage.