Hertel K008355AS 1/4-28 Unf Straight Flute Tap Hss Plug

Product Description

The HERTEL K008355AS is a straight flute tap designed for cutting internal 1/4-28 UNF right-hand threads in a wide range of materials. Built from high-speed steel with a bright, uncoated finish, this tap delivers reliable performance in general-purpose threading applications. The plug chamfer — typically 3 to 5 threads — allows for use in both through-holes and deeper blind holes when working clearance permits. With a 3-flute configuration and an H3 thread limit, the K008355AS maintains dimensional control appropriate for a 3B class of fit. Overall length is 2.5 inches, and the tool weighs 0.35 pounds. Machinists, tool-and-die workers, and maintenance technicians reach for this tap when precision UNF thread production is required.

This tap is suited for threading operations in ferrous and non-ferrous metals, plastics, and similar materials where a 1/4-28 UNF thread form is specified. The straight flute geometry works well in shorter-chipping materials and is common in manual tapping, drill press, and light CNC or turret applications. The plug chamfer style makes it a standard first-choice tool when both through-hole and shallow blind-hole work is anticipated on the same job. It is packaged individually and sold as a single-piece unit.

Key Features

• 1/4-28 UNF thread size with right-hand thread direction
• Plug chamfer for versatile use in through-holes and accessible blind holes
• 3 straight flutes suited to shorter-chipping materials
• H3 thread limit maintains dimensional tolerance for 3B class of fit
• High-speed steel construction provides good wear resistance in general-purpose threading
• Bright, uncoated finish — compatible with standard cutting fluids

Compatibility

Designed as a standard 1/4-28 UNF straight flute plug tap suitable for use with manual tap handles, tapping heads, and machine tool setups that accept standard tap shanks in this size range.

Installation Notes

Tapping should be performed by a qualified machinist or maintenance technician familiar with thread-cutting procedures and appropriate cutting fluid selection for the workpiece material. Secure the workpiece firmly and ensure the tap is started perpendicular to the surface to avoid thread distortion or tap breakage. Always apply cutting fluid appropriate to the material being tapped, and back the tap off periodically to break chips when working in deeper holes. Worn or damaged taps should be replaced before use to prevent thread damage or tool failure.