Balax 12890-000 Thread Forming Tap 1/4-28 Unf Plug Hss

Product Description

The BALAX 12890-000 is a thread forming tap designed for through-hole threading in a variety of production and maintenance machining applications. Unlike cut taps, thread forming taps displace material rather than cutting it, producing stronger threads with no chips to clear. This plug-style tap is manufactured from high-speed steel with a bright uncoated finish and carries an H10 thread limit, making it well suited for work in softer metals and ductile materials. It measures 2.5 inches in overall length with a thread length of 0.79 inches and a tapping depth of 1.0 inch. The shank diameter is 0.255 inches with a 0.191-inch square drive. Installation is performed by machinists and tooling technicians using a standard tap wrench or CNC tapping head.

This tap is used in through-hole threading operations where chip-free forming is preferred over conventional cutting. The plug chamfer provides a gradual lead-in of four chamfered threads, making it a practical choice for through-holes in production runs or repair work. The BXP series designation indicates it is built for general-purpose forming applications. Typical installations include threading pre-drilled through-holes in aluminum, brass, and other ductile metals in manufacturing, fabrication, and mechanical assembly environments.

Key Features

• Thread forming design displaces material for stronger, chip-free threads
• 1/4-28 UNF right-hand thread specification
• Plug chamfer with four chamfered threads for smooth lead-in
• High-speed steel construction with bright uncoated finish
• H10 thread limit for consistent dimensional control
• Single oil groove to aid lubrication during forming
• 2.5-inch overall length with 0.191-inch square drive shank

Compatibility

Designed for through-hole threading operations requiring a 1/4-28 UNF right-hand thread in ductile materials. Compatible with standard tap wrenches, T-handle holders, and CNC tapping heads accepting a 0.255-inch shank diameter with a 0.191-inch square drive.

Installation Notes

Thread forming taps require a specific forming tap drill size - do not use a standard cut tap drill chart, as the recommended hole diameter is larger than for cut taps. Apply a suitable tapping fluid or cutting oil appropriate for the workpiece material before and during tapping. Secure the workpiece fully before operation to prevent movement. Inspect the tap for wear or deformation before each use, and replace if thread quality degrades.