Hertel K010369AS25 Thread Forming Tap 1/4-20 Unc Bottoming

Product Description

The HERTEL K010369AS25 is a thread forming tap designed for creating 1/4-20 UNC internal threads in blind holes without generating chips. Unlike cutting taps, this forming tap displaces material to produce threads, resulting in stronger thread geometry and a cleaner hole. Built from high-speed steel with a titanium nitride coating, it delivers improved surface hardness and extended tool life compared to uncoated HSS. The bottoming chamfer — with 1 to 2 chamfered threads — allows threading to the bottom of a blind hole with minimal clearance. Overall length is 2.5 inches with a 1-inch thread length. Installed using a standard tap driver or CNC rigid tapping cycle by machinists and maintenance professionals.

This tap is suited for blind hole threading in ductile metals where chip-free forming is preferred. Typical applications include threading aluminum, mild steel, and other machinable alloys in production machining, maintenance repair, and toolroom environments. The right-hand thread direction and H4 thread limit make it a reliable choice for standard UNC tapping operations requiring close tolerance control in bottoming situations where full thread engagement depth is critical.

Key Features

• Thread forming design displaces material rather than cutting, producing stronger threads and eliminating chip removal concerns in blind holes
• Titanium nitride coating increases surface hardness and reduces friction for longer tool life
• High-speed steel construction provides toughness for hand and machine tapping applications
• Bottoming chamfer with 1 to 2 chamfered threads allows threading to the bottom of blind holes
• H4 thread limit suitable for close-tolerance UNC thread production
• Right-hand thread direction for standard tapping operations

Compatibility

Designed as an OEM-style replacement or direct-use thread forming tap for standard 1/4-20 UNC blind hole threading applications in compatible tap holders and CNC rigid tapping setups.

Installation Notes

Thread forming taps require the correct drill size for the material and thread form — consult a thread forming drill chart before drilling the pilot hole, as the required hole diameter differs from that used with cutting taps. Ensure the workpiece is securely fixtured and the tap is properly aligned to avoid tap breakage. Apply cutting fluid or tapping compound appropriate for the workpiece material before and during the tapping operation. This tap should be installed and operated by qualified machinists familiar with tapping speeds, feeds, and torque limitations for the tool diameter.