Hertel K008631AS Straight Flute Tap 1-8 Unc Bottoming Hss

Product Description

The HERTEL K008631AS is a straight flute bottoming tap designed to cut unified national coarse (UNC) internal threads in a 1-8 thread size. Built from high speed steel (HSS) with a bright uncoated finish, it delivers consistent thread form in through-holes and blind holes where full thread depth near the bottom is required. With 4 flutes and an H4 thread limit, this tap is suited for machinists and toolroom techs working in ferrous and non-ferrous materials where chip evacuation is manageable and dimensional accuracy is critical. Overall length is 5.125 inches.

This tap is used in general machining, maintenance repair, and manufacturing applications requiring UNC threaded holes. The bottoming chamfer - typically 1 to 2 thread leads - allows threading to within a few pitches of a blind hole bottom. Class 3B fit designation means it produces close-tolerance threads appropriate for precision assemblies. Right-hand thread direction follows standard practice for the majority of fastener applications in industrial and mechanical trade work.

Key Features

• Bottoming chamfer cuts threads close to the bottom of blind holes
• 4 straight flutes provide chip control in shorter-chipping materials
• H4 thread limit supports consistent 3B class fit tolerances
• High speed steel construction handles a broad range of workpiece materials
• Bright uncoated finish suitable for use with cutting fluid in standard machining operations
• Right-hand cut, 1-8 UNC thread form matches the most common coarse-thread fastener standard

Compatibility

Designed as an OEM-style replacement or direct-use straight flute bottoming tap for machine tool spindles and hand tapping setups requiring a 1-8 UNC thread form with 3B class fit.

Installation Notes

Secure the tap in a properly sized tap holder or tapping chuck before use; never run a bottoming tap into an unprepared hole without first using plug and taper taps to establish the thread lead. Ensure the workpiece is firmly fixtured and apply an appropriate cutting fluid for the base material to reduce heat and extend tool life. Inspect the tap for chipped or worn flutes before each use - a damaged tap in a blind hole can result in a broken tap extraction that damages the workpiece.