Accupro T2640585 Spiral Point Tap 1/2-20 3 Flutes Plug 2B

Product Description

The ACCUPRO T2640585 is a spiral point tap designed for cutting 1/2-20 UNF internal threads in steel and similar materials. Spiral point taps, also called gun taps, push chips ahead of the cut rather than backing them into the flutes, making them well suited for through-hole tapping operations. This tap is manufactured from 3 percent vanadium high-speed steel, which provides added wear resistance and edge retention compared to standard M2 HSS. Key specs include a plug chamfer for gradual thread engagement, a 2B class of fit tolerance, and an H5 thread limit. The bright uncoated finish makes it a reliable general-purpose choice for shop and field threading work. A licensed machinist or tool-and-die technician would typically use this tap on a drill press, tapping arm, or CNC machine.

This tap is intended for tapping through-holes in steel workpieces where a 1/2-20 UNF thread form is required. The plug chamfer, which typically features 3 to 5 starting threads, allows for moderate lead-in and is the most common chamfer style used in production and maintenance environments. The 3-flute geometry provides good chip clearance in medium-hardness steels. With an overall length of 3.375 inches and a thread length of approximately 1.14 inches (29 mm), this tap fits standard tap wrenches and tapping chucks sized for a 9.32 mm shank diameter. It is appropriate for both manual and machine tapping applications.

Key Features

• 1/2-20 UNF thread size with right-hand thread direction
• 3-flute spiral point design pushes chips forward through the hole
• Plug chamfer provides gradual thread engagement for through-hole tapping
• Vanadium high-speed steel (3 percent vanadium) for improved wear resistance over standard HSS
• H5 thread limit with 2B class of fit for standard UNF tolerance requirements
• Bright uncoated finish suitable for use with cutting oil on steel

Compatibility

Designed for tapping 1/2-20 UNF through-holes in steel. The 9.32 mm shank diameter is compatible with standard tap chucks and tap wrenches sized for that shank. Material application is rated for steel per supplier data.

Installation Notes

Always secure the workpiece and ensure the tap is aligned perpendicular to the drilled hole before beginning the threading operation. Apply an appropriate cutting fluid for steel to extend tap life and improve thread quality. Use a properly sized tap wrench or machine chuck rated for the shank diameter, and do not exceed the recommended torque for the tap size to avoid breakage. Broken tap removal is time-consuming — avoid forcing the tap if resistance increases unexpectedly.