Accupro T2634165 Spiral Flute Tap 4-40 3 Flute Hss

Product Description

The ACCUPRO T2634165 is a spiral flute tap designed to cut 4-40 unified coarse threads in blind and through holes. It features a modified bottoming chamfer, which allows threading close to the bottom of a blind hole while still providing enough lead-in for accurate thread engagement. Constructed from 3% Vanadium High Speed Steel with a bright uncoated finish, this tap delivers solid wear resistance in steel and similar ferrous materials. With a 33-degree helix angle and medium flute style, it evacuates chips upward efficiently, reducing the risk of chip packing in confined bores. The right-hand flute and right-hand thread configuration is the standard orientation for machine and hand tapping operations.

This tap is suited for production and maintenance tapping in steel workpieces where 4-40 threads are required. Typical applications include threading small fastener holes in sheet metal, brackets, enclosures, and precision assemblies. The 3-flute design provides a balance of strength and chip clearance, making it appropriate for CNC tapping centers, drill presses with tapping attachments, and hand tapping. It is sized for use in trade and industrial environments where consistent thread quality at the 4-40 standard is critical.

Key Features

• Modified bottoming chamfer allows threading to near the bottom of blind holes
• 3% Vanadium High Speed Steel construction provides improved wear resistance over standard M2 HSS
• 33-degree helix angle promotes upward chip evacuation in blind hole applications
• Right-hand flute and right-hand thread — standard orientation for general tapping
• Bright uncoated finish suitable for general-purpose steel tapping with appropriate cutting fluid
• H5 thread limit for controlled tolerance fit in standard 4-40 threaded assemblies

Compatibility

Designed for tapping 4-40 unified coarse threads in steel materials. Compatible with standard 4-40 tap holders, collets, and tapping heads sized for the 3.58 mm shank diameter.

Installation Notes

This tap should be installed by a machinist or qualified trades professional familiar with threading operations. Always secure the workpiece before tapping and use a cutting fluid appropriate for the work material to extend tap life and improve thread quality. When tapping blind holes, avoid bottoming the tap under power to prevent breakage. Inspect tap condition regularly and replace at the first sign of dull cutting edges or excessive torque.