Import BDNA-22597 Hand Sti Tap 7/16-20 Unf H3 4 Flutes

Product Description

The IMPORT BDNA-22597 is a hand STI tap designed for cutting and restoring threads in Heli-Coil insert applications. Sized at 7/16-20 UNF with an H3 thread limit, it produces threads sized to accept standard wire thread inserts. The 4-flute, plug chamfer geometry provides a balance of cutting performance and chip clearance suited to through-holes and moderately deep blind holes. Manufactured from high-speed steel with a bright uncoated finish, this tap is a dependable choice for machinists, maintenance technicians, and field repair professionals working with threaded insert repairs.

This tap is used wherever a damaged or stripped 7/16-20 UNF thread needs to be restored using a Heli-Coil or equivalent wire thread insert. Common applications include automotive, aerospace, and industrial maintenance shops where fastener threads have been damaged and a full insert repair is required. The plug chamfer style makes it well-suited for starting in pre-drilled holes and advancing through the material with consistent thread form. It carries a Helicoil Reference Number of 7FPB.

Key Features

• 7/16-20 UNF thread size for STI insert preparation
• H3 thread limit ensures proper fit for wire thread inserts
• 4-flute design balances chip evacuation and thread surface quality
• Plug chamfer provides easy starting in through-holes and open blind holes
• High-speed steel construction for durability across a range of workpiece materials
• Bright uncoated finish — no coating buildup that could affect thread tolerance

Compatibility

Designed for use in STI (Screw Thread Insert) tap applications requiring a 7/16-20 UNF thread form with H3 tolerance; compatible with Heli-Coil insert systems referencing part number 7FPB.

Installation Notes

This tap should be installed by a qualified machinist or maintenance technician familiar with thread insert repair procedures. Always ensure the workpiece is securely fixtured and the pre-drilled hole matches the STI tap drill size before tapping. Use appropriate cutting fluid for the workpiece material to extend tap life and improve thread quality. Back the tap out periodically to clear chips, particularly in deeper holes or harder materials.