Hertel K008529AS Straight Flute Tap 1/2-20 Unf Hss

Product Description

The HERTEL K008529AS is a straight flute tap designed to cut internal threads in a wide range of materials encountered in precision machining, maintenance, and fabrication work. Built from high-speed steel (HSS) with a bright/uncoated finish, it cuts a 1/2-20 UNF right-hand thread to a 3B class of fit with an H3 thread limit. The taper chamfer — typically 7 to 10 threads — eases the tap into the starting hole and helps distribute cutting load across multiple flutes. With 4 flutes and a 3.375-inch overall length, this tap suits through-hole and short blind-hole applications where chip flow is not severely restricted.

This tap is appropriate for general-purpose threading in ferrous and non-ferrous metals, plastics, and similar machinable materials. It fits production, job-shop, and field-maintenance scenarios where a taper-start tap is the preferred entry for starting a new thread or re-tapping a damaged hole. Machinists, toolmakers, and maintenance technicians working on equipment that uses 1/2-20 UNF fasteners will find this a standard go-to tool for hand tapping or low-speed machine tapping operations.

Key Features

• 1/2-20 UNF thread form with H3 thread limit for consistent 3B class of fit
• Taper chamfer distributes cutting load for easier thread entry and reduced tap breakage risk
• 4-flute straight design suitable for through holes and short blind holes in most common materials
• High-speed steel construction provides good wear resistance across a broad range of workpiece materials
• Bright/uncoated finish allows direct inspection of tool wear and is compatible with most cutting fluids
• Right-hand thread direction — standard for the vast majority of UNF fastener applications

Compatibility

Designed as a general-purpose OEM-style straight flute tap for applications requiring a 1/2-20 UNF internal thread to 3B class of fit tolerances.

Installation Notes

This tap is installed by machinists or maintenance technicians using a tap wrench, T-handle, or low-speed tapping head. Ensure the workpiece is securely fixtured and the pilot hole is drilled to the correct tap drill size for a 1/2-20 UNF thread before starting. Apply an appropriate cutting fluid for the workpiece material and reverse direction periodically during hand tapping to break chips. Never force the tap against excessive resistance — back it out to clear chips before continuing to reduce the risk of breakage.