Balax 12992-91L Thread Forming Tap 1/4-28 Unf Bottoming

Product Description

The BALAX 12992-91L is a thread forming tap designed for blind hole threading in die cast aluminum. It cuts no chips - instead, it cold-forms the thread by displacing material, producing a stronger thread form with a better surface finish than cut taps. Sized for 1/4-28 UNF threads with a 2B class of fit and H7 thread limit, this tap is built from powdered metal high-speed steel (PM-HSS) and finished with BALAX Bal-Plus coating to extend tool life in production and maintenance environments. Machinists and tool-and-die technicians reach for this tap when threading soft, ductile materials at volume.

This tap is suited for blind hole applications in die cast aluminum components, which is where the BXDIECAST series excels. The bottoming chamfer - with 2.5 chamfered threads - allows threading close to the bottom of a blind hole, maximizing thread engagement in tight-depth applications. It is commonly used in automotive, HVAC equipment manufacturing, and general metalworking where die cast aluminum housings require threaded inserts or fastener holes. The right-hand thread direction is standard for conventional machine tapping operations.

Key Features

• Thread forming (chipless) design eliminates chip-clearing concerns in blind holes
• Powdered metal high-speed steel construction for improved toughness and wear resistance over conventional HSS
• Bal-Plus coating reduces friction and extends service life in aluminum applications
• Bottoming chamfer with 2.5 chamfered threads for maximum thread depth in blind holes
• H7 thread limit for 2B class of fit - standard for most general-purpose threaded fastener applications
• Single oil groove supports lubrication during the forming process

Compatibility

Designed for blind hole thread forming in die cast aluminum. Sized for 1/4-28 UNF threads, 2B class of fit, with an H7 thread limit. Part of the BALAX BXDIECAST series.

Installation Notes

Thread forming taps require a specific tap drill size larger than that used for cut taps - consult a thread forming drill chart for the correct 1/4-28 UNF forming drill diameter before use. Always apply a suitable tapping fluid or cutting oil rated for aluminum before and during tapping. Secure the workpiece firmly and ensure the tap enters the hole square to avoid thread distortion or tap breakage. Power down and lock out any machine spindle before changing or inspecting taps.