Hertel K017189AS Spiral Point Tap 3/8-24 Unf Left Hand

Product Description

The HERTEL K017189AS is a left-hand spiral point tap designed to cut 3/8-24 UNF internal threads in through-hole applications. Manufactured from high-speed steel with a bright, uncoated finish, this plug-chamfer tap pushes chips forward ahead of the cutting zone, making it well suited for threading operations on through-holes where chip evacuation is critical. It carries a 3B class of fit and an H3 thread limit, delivering the tolerance control required for standard fastener assemblies. Machinists and tool-and-die professionals specify this tap for production runs and repair work where a left-hand thread is required by design or to counteract rotational loosening.

This tap is intended for left-hand through-hole tapping in ferrous and non-ferrous workpiece materials commonly encountered in machine shop, maintenance, and repair environments. The plug chamfer profile — typically 3 to 5 threads of lead — allows starting in a drilled hole and is a standard choice for general-purpose through-hole threading on CNC machining centers, turret lathes, and manual knee mills. It is not designed for blind-hole applications where chip packing would be a concern.

Key Features

• Left-hand thread direction for applications requiring reverse-thread fastener engagement
• Spiral point geometry pushes chips forward, reducing chip packing in through-holes
• High-speed steel construction provides toughness across a range of workpiece materials
• Plug chamfer provides stable entry and is standard for through-hole production tapping
• H3 thread limit and 3B class of fit for consistent, tolerance-controlled thread form
• Bright, uncoated finish — compatible with standard cutting fluids without coating interaction

Compatibility

Designed as a direct-use left-hand spiral point tap for 3/8-24 UNF through-hole tapping in standard tap holders, quick-change tapping heads, and floating tap adapters that accept straight-shank taps of this size class.

Installation Notes

This tap should be installed by a qualified machinist following established tapping procedures. Ensure the tap is properly aligned with the drilled pilot hole before engagement to avoid tap breakage or thread distortion. Use an appropriate cutting fluid for the workpiece material; do not run this tap dry in ferrous materials. Secure the tap in a holder rated for the torque generated at the selected RPM, and verify the direction of spindle rotation matches the left-hand thread direction before beginning the cut.