Balax 12727-010 Thread Forming Extension Tap 1/4-20 H7 Hss

Product Description

The BALAX 12727-010 is a thread forming extension tap designed for producing strong, clean internal threads in ductile materials without cutting chips. Built from high-speed steel with a bright, uncoated finish, it carries a 1/4-20 UNC thread specification and an H7 thread limit for precise tolerance control. The 6-inch overall length gives technicians extended reach into deep bores or recessed features that standard-length taps cannot access. This bottoming chamfer style starts threading to the bottom of a blind hole, making it the right choice when full thread depth is critical. It is used by machinists, tool and die makers, and maintenance mechanics in production and repair environments.

This tap suits applications in ferrous and non-ferrous ductile materials where chip-free thread forming is preferred over cutting. The bottoming chamfer makes it especially useful in blind-hole setups requiring maximum thread engagement near the base of the hole. The BXEXT series design accommodates use in CNC machining centers, drill presses, and manual tapping operations where extended reach is needed. Its right-hand flute direction and 2B class of fit align with standard UNC fastener assembly requirements common in general manufacturing, HVAC equipment fabrication, and light structural work.

Key Features

• Thread forming design eliminates chips, reducing tap breakage risk in ductile materials
• Bottoming chamfer allows full thread depth in blind holes
• 6-inch overall length provides extended reach into deep or recessed bores
• H7 thread limit ensures consistent tolerance for 2B class of fit assemblies
• High-speed steel construction offers durability across a range of tapping speeds
• Bright, uncoated finish suitable for use with standard cutting fluids and tapping compounds

Compatibility

Designed as an OEM-style replacement or direct-use thread forming tap for 1/4-20 UNC tapping applications requiring a bottoming chamfer and extended reach, fitting standard tap holders and extensions compatible with a 0.255-inch shank diameter.

Installation Notes

Thread forming taps require a specific tap drill size matched to the material for proper thread formation; consult a thread forming drill chart before use. Always apply appropriate tapping fluid or compound and ensure the workpiece is securely clamped before tapping. Disengage power and secure the machine before changing or inspecting taps. Right-hand tapping direction must be confirmed on CNC or power-tapping setups before engaging the spindle.