Hertel K010369AS85 Thread Forming Tap 1/4-20 Unc

Product Description

The HERTEL K010369AS85 is a bottoming thread forming tap designed for cold-forming internal threads in ductile metals without cutting or producing chips. Sized at 1/4-20 UNC with a right-hand thread direction, this tap displaces material rather than removing it, resulting in stronger thread flanks and longer tool life compared to cut taps. It is manufactured from high-speed steel and carries a TiCN coating for improved surface hardness and wear resistance. With an overall length of 2.5 inches and a thread length of 1 inch, it is suited to controlled-depth threading in production and maintenance environments. Licensed machinists and toolroom technicians are the primary installers.

This tap is intended for blind hole threading applications where chip evacuation is a concern or where thread strength requirements favor a formed thread over a cut thread. The bottoming chamfer style, with 1 to 2 chamfered threads, allows threading close to the bottom of a blind hole. Typical applications include threading aluminum, mild steel, and other ductile metals in manufacturing, repair, and fabrication settings. The H4 thread limit accommodates standard tolerance requirements for 1/4-20 UNC fastener fits.

Key Features

• Thread forming design eliminates chips, reducing risk of chip packing in blind holes
• TiCN coating increases surface hardness and extends tool life in abrasive and high-cycle applications
• Bottoming chamfer with 1-2 chamfered threads allows threading to near full depth in blind holes
• H4 thread limit for standard 1/4-20 UNC tolerance requirements
• Right-hand thread direction for standard tapping operations
• High-speed steel construction for toughness in interrupted cuts and variable-speed setups

Compatibility

Designed for use in blind hole threading applications requiring a 1/4-20 UNC right-hand internal thread in ductile metals; verify workpiece material is suitable for thread forming before use.

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 hole diameter before drilling. Secure the workpiece and use a calibrated tap handle or CNC tapping cycle with appropriate feed rate to avoid tap breakage. Apply a suitable tapping fluid or cutting oil rated for the workpiece material. Inspect the tap for wear or chipping regularly and replace before thread quality degrades.