Balax 12905-010 Thread Forming Tap 1/4-28 Unf Bottoming

Product Description

The BALAX 12905-010 is a thread forming tap designed for cutting 1/4-28 UNF internal threads in blind hole applications. Unlike cutting taps, thread forming taps displace material rather than remove chips, producing stronger threads with a burnished surface finish. This tap is built from high-speed steel with a bright uncoated finish and features a bottoming chamfer with 1.5 threads of lead, allowing threading close to the bottom of a blind hole. Overall length is 2.5 inches with a thread length of 0.79 inches and a tapping depth of 1.0 inch. It is suited for use in ductile metals and is installed by machinists and maintenance technicians in production and repair environments.

This tap is used in blind hole threading operations where full thread depth close to the hole bottom is required. The bottoming chamfer configuration makes it appropriate as a finishing tap following a plug or taper tap when threading to depth in a confined bore. Typical applications include threaded fastener holes in metal brackets, housings, and structural components machined to UNF standards. The Series BXOTL designation applies to BALAX thread forming taps in this product family.

Key Features

• Bottoming chamfer with 1.5 chamfered threads for threading close to blind hole bottom
• Thread forming design displaces material rather than cutting, producing stronger, chip-free threads
• High-speed steel construction for durability in ductile metal applications
• Right-hand thread direction, 1/4-28 UNF thread standard
• H5 thread limit for Class 2B and 3B fit tolerance
• Single oil groove design; overall length 2.5 inches, shank diameter 0.255 inches

Compatibility

Designed for blind hole threading of 1/4-28 UNF right-hand threads in ductile metals, compatible with Class 2B and 3B fit requirements per UNF thread standards.

Installation Notes

Thread forming taps require a correctly sized forming tap drill hole, which differs from standard cut tap drill sizes - consult a thread forming drill chart before drilling. Apply appropriate tapping fluid or cutting oil rated for the workpiece material before tapping. Use a calibrated torque wrench or tapping attachment to avoid over-torquing, which can fracture the tap or strip the formed thread. Ensure the workpiece is securely fixtured and the tap is aligned perpendicular to the hole before engagement.