Import BDNA-22599 Hand Sti Tap 1/2-20 Unf H3 4 Flutes

Product Description

The IMPORT BDNA-22599 is a hand STI (Screw Thread Insert) tap designed to cut 1/2-20 UNF internal threads in preparation for Helicoil-style thread insert installation. It features a plug chamfer for starting in through-holes or moderately deep blind holes, a H3 thread limit for controlled fit tolerances, and 4 flutes for efficient chip evacuation. Manufactured from high-speed steel with a bright uncoated finish, this tap delivers consistent performance in general-purpose threading applications. The overall length is 3-19/32 inches with a thread length of 1-21/32 inches. Licensed tradespeople and machinists use this tool for thread repair and insert preparation work.

This tap is suited for thread repair applications in residential and commercial maintenance, manufacturing, and field service environments. It is used wherever a 1/2-20 UNF thread insert is being installed to restore damaged or stripped threads in metal components. The Helicoil reference number is 8FPB, making cross-referencing to compatible insert kits straightforward. Typical applications include engine components, hydraulic fittings, and mechanical assemblies that require a precise UNF thread form.

Key Features

• 1/2-20 UNF thread form for standard unified fine-pitch threading
• H3 thread limit for consistent tolerance control on thread fit
• 4-flute geometry promotes efficient chip removal during cutting
• Plug chamfer allows starting in through-holes and moderately deep blind holes
• High-speed steel construction provides durability across a range of workpiece materials
• Bright uncoated finish suitable for use with standard cutting fluids

Compatibility

Designed for use with Helicoil-style screw thread insert systems; Helicoil reference number 8FPB. Intended for STI tap applications requiring a 1/2-20 UNF thread form with H3 limit.

Installation Notes

This tap is installed by hand using a tap wrench and should be used with an appropriate cutting fluid for the workpiece material. Ensure the workpiece is secured before tapping and that the tap is started square to the hole to avoid cross-threading. Follow the thread insert manufacturer's instructions for correct tap drill size selection prior to use. Proper chip clearing technique is recommended, especially in blind-hole applications.