Heli-coil 6CSB Spiral Point Sti Tap 3/8-16 Unc

Product Description

The HELI-COIL 6CSB is a spiral point STI tap designed to cut threads for Screw Thread Inserts in 3/8-16 UNC applications. Ground from high-speed steel with a bright, uncoated finish, it features a plug chamfer and three flutes that push chips forward ahead of the tap, keeping them clear of the cutting zone. It is built to an H3 thread limit and 3B class of fit, ensuring accurate thread form for insert installation. Licensed HVAC technicians, plumbers, maintenance mechanics, and industrial trades rely on STI taps to restore stripped or damaged threaded bores to their original specifications.

This tap is used wherever a Heli-Coil or compatible screw thread insert is being installed, including residential and commercial HVAC equipment, plumbing fixtures, pumps, compressors, and general mechanical assemblies. It is suited for through-hole and blind-hole applications in ferrous and non-ferrous materials where a standard 3/8-16 UNC thread is required after insert installation. With an overall length of 3.375 inches and a thread length of approximately 1.656 inches, it fits standard tap handles and machine spindles used in field and shop settings.

Key Features

• Spiral point design pushes chips forward, reducing clogging in through-hole applications
• High-speed steel construction provides durability across ferrous and non-ferrous materials
• Plug chamfer offers a balance between starting ease and thread engagement depth
• H3 thread limit and 3B class of fit deliver consistent accuracy for insert-ready threads
• 3-flute geometry suits hand tapping and light machine tapping operations
• Bright, uncoated finish allows easy visual inspection of cutting edges before and after use

Compatibility

Designed for use with Heli-Coil and compatible screw thread inserts requiring a 3/8-16 UNC STI tapped hole prior to insert installation.

Installation Notes

Install using a calibrated tap handle or machine spindle rated for the material being tapped; ensure the workpiece and equipment are secured before beginning. Power down or de-energize any equipment being serviced before tapping threads into a live assembly. Apply appropriate cutting fluid for the base material to extend tap life and improve thread finish. Follow NEC, IFGC, or IPC guidelines as applicable to the system being repaired, and verify thread form with a go/no-go gauge after tapping.