Hertel K008305AS Straight Flute Tap 12-28 Unf Hss

Product Description

The HERTEL K008305AS is a straight flute tap designed to cut 12-28 UNF internal threads in a variety of workpiece materials. Built from high-speed steel (HSS) with a bright, uncoated finish, this tap is suited for general-purpose threading operations in machine shop and maintenance environments. It features 4 straight flutes with a plug chamfer, a right-hand thread direction, and an H3 thread limit for close tolerance work. Overall length is 2.375 inches, and the part weighs 0.28 pounds. It is intended for use by machinists, toolmakers, and maintenance technicians performing precision threading tasks.

This tap is designed for threading 12-28 UNF holes in ferrous and non-ferrous metals, plastics, and similar materials where straight flute geometry is appropriate. The plug chamfer makes it suitable for through-hole threading applications, providing a gradual thread lead-in over several starting threads. The 2B/3B class of fit accommodates standard UNF fastener tolerances used widely in industrial and mechanical assembly applications.

Key Features

• 12-28 UNF thread form with right-hand direction and H3 thread limit for precise fit
• Plug chamfer provides gradual thread lead-in, ideal for through-hole applications
• 4 straight flutes for chip clearance in moderate-depth threading operations
• High-speed steel construction for durability across a range of workpiece materials
• Bright, uncoated finish — no coating buildup to affect thread tolerance
• Class of fit 2B/3B accommodates standard UNF fastener assembly tolerances

Compatibility

Designed as an OEM-style replacement or direct-use straight flute tap for applications requiring 12-28 UNF internal threads with a 2B or 3B class of fit.

Installation Notes

This tap is installed by machinists or maintenance technicians using a tap wrench, tapping head, or machine spindle. Ensure the pilot hole is drilled to the correct tap drill size for 12-28 UNF before beginning. Apply appropriate cutting fluid to extend tool life and improve thread quality. Follow standard shop safety practices and secure the workpiece firmly before tapping.