Balax 10723-010 Thread Forming Tap 4-40 Unc Bottoming Hss

Product Description

The BALAX 10723-010 is a bottoming-chamfer thread forming tap designed for blind hole threading in 4-40 UNC applications. Unlike cutting taps, thread forming taps displace material rather than remove it, producing stronger threads with no chips to clear from the hole. This tap is manufactured from high-speed steel with a bright uncoated finish and carries an H3 thread limit for consistent tolerance control. The 2.5-thread chamfer length positions this as a bottoming tap, allowing threads to be formed close to the bottom of a blind bore. It is suited for use by machinists, tool and die makers, and maintenance technicians working with small-diameter fastener threads.

This tap is intended for blind hole threading in soft to medium-hardness workpiece materials where chipless thread forming is preferred. The 4-40 UNC thread size is common in precision assemblies, electronics enclosures, instrumentation panels, and light mechanical hardware. The right-hand thread direction and standard shank geometry make it compatible with conventional tap wrenches and tapping heads used in manual and machine tapping operations. Series BXB designation identifies the BALAX product line for this geometry.

Key Features

• Thread forming (chipless) design produces stronger threads and eliminates chip clearing in blind holes
• Bottoming chamfer with 2.5 chamfered threads allows threading close to the bottom of a blind bore
• H3 thread limit for controlled tolerance fit to 3B class specifications
• High-speed steel construction provides durability across a range of workpiece materials
• Bright uncoated finish suitable for use with standard tapping fluids and oils
• No coolant-through feature keeps design simple for hand and light machine tapping

Compatibility

Designed for blind hole threading applications requiring 4-40 UNC, Class 3B fit. Compatible with standard tap wrenches and tapping heads accepting a 0.141-inch shank diameter.

Installation Notes

Thread forming taps require a properly sized forming tap drill hole, which is typically larger than a standard cut-tap drill size for the same thread - consult a thread forming tap drill chart before drilling. Adequate lubrication with a suitable tapping fluid is required to prevent galling and tap breakage, especially in harder materials. Ensure the workpiece is securely fixtured and the tap is started square to the hole. Follow standard shop safety practices and machine guarding requirements when tapping under power.