Accupro T1604502B Spiral Flute Tap 3/8-24 Modified Bottoming

Product Description

The ACCUPRO T1604502B is a spiral flute tap designed for cutting 3/8-24 UNF internal threads in a wide range of materials. It features three fast-helix right-hand flutes set at a 40-degree helix angle, which efficiently evacuates chips upward out of the hole during tapping — a key advantage when working in blind-hole applications. The tap is ground from 3 percent vanadium high-speed steel for improved wear resistance over standard M2 HSS, and carries an oxide finish that provides light corrosion protection and reduces friction during the cut. Thread fit is 2B class, the standard for most general-purpose UNF fastener assemblies. Overall length is 2-15/16 inches with a 16 mm thread length and a 9.68 mm shank diameter.

This tap is suited for use in machine shops, maintenance and repair operations, and production environments where UNF 3/8-24 blind-hole threads are required. The modified bottoming chamfer style features a 1 to 2 thread chamfer lead, allowing threads to be cut closer to the bottom of a blind hole than a plug or taper tap while still providing adequate guidance on entry. It is intended for use in CNC machining centers, drill presses, and tapping machines as well as manual hand-tapping operations. No coolant-through capability is incorporated, so external cutting fluid application is recommended for best tool life.

Key Features

• 3/8-24 UNF thread form with 2B class of fit for standard general-purpose assemblies
• Modified bottoming chamfer for threading closer to the bottom of blind holes
• 40-degree fast helix flute design promotes efficient chip evacuation in blind-hole tapping
• 3 percent vanadium high-speed steel construction for enhanced wear resistance over standard HSS
• Oxide coating reduces friction and provides light protection against corrosion
• Right-hand thread and right-hand flute direction for standard CW tapping operations

Compatibility

Designed as a direct-fit replacement for standard 3/8-24 spiral flute machine taps with a 9.68 mm shank diameter. Compatible with standard tap holders and floating tap heads sized for the shank diameter.

Installation Notes

This tap is installed and used by machinists and tool and die professionals in metalworking operations. Always secure the workpiece fully before tapping and ensure the pilot hole diameter is correct for the 3/8-24 thread form before starting. Apply appropriate cutting fluid to the tap and hole throughout the operation to reduce heat buildup and extend tool life. When tapping blind holes, monitor thread depth carefully to avoid bottoming the tap under torque load, which can cause tap breakage.