Balax 10784-010 Extension Thread Forming Tap 4-40 H4

Product Description

The BALAX 10784-010 is a high speed steel extension thread forming tap designed for cutting 4-40 UNC internal threads in ductile materials. Thread forming taps displace material rather than cutting it, producing stronger, cleaner threads with no chips to clear from blind holes. This tap features a bottoming chamfer for threading to the bottom of a hole, a H4 thread limit for controlled fit, and a 3-inch overall length suited for reaching recessed or deep-set hole locations. It is used by machinists, tool and die makers, and precision assembly technicians working in production or maintenance environments.

The BALAX 10784-010 is suited for applications requiring 4-40 UNC threads in materials such as aluminum, brass, mild steel, and other chip-free-forming alloys. The BXEXT series extension design provides added reach over standard-length taps, making it practical for tapping holes in deep pockets, fixtures, and assemblies where standard tap length is insufficient. The bottoming chamfer allows full thread engagement close to the bottom of blind holes, a common requirement in precision component assembly.

Key Features

• Thread forming design displaces material for stronger threads and eliminates chip interference in blind holes
• Bottoming chamfer allows threading to the base of blind holes
• H4 thread limit provides consistent 3B class of fit for controlled tolerance threading
• Extended 3-inch overall length reaches recessed hole locations inaccessible to standard taps
• High speed steel construction offers durability across a range of ductile workpiece materials
• Bright uncoated finish suitable for use with standard tapping fluids

Compatibility

Designed for tapping 4-40 UNC threads with a 3B class of fit in applications requiring an extension-length bottoming tap of the BXEXT series.

Installation Notes

Thread forming taps require adequate lubrication with a suitable tapping fluid to prevent galling and tool wear. Ensure the tap is properly aligned with the pre-drilled hole before applying torque, as misalignment can damage threads or break the tap. Use a calibrated tap wrench or CNC tapping head with appropriate torque control. Power down any machine spindle and secure the workpiece firmly before beginning the tapping operation.