Accupro T1640643 Spiral Point Tap 5/8-11 4 Flutes Cobalt

Product Description

The ACCUPRO T1640643 is a spiral point tap designed for threading 5/8-11 UNC holes in ferrous and hard materials. Built from HSS-E cobalt steel with an oxide finish, it drives chips forward through the hole rather than packing them in the flutes — making it the standard choice for through-hole tapping on a drill press, CNC machining center, or tapping head. The plug chamfer (3-5 thread lead-in) provides a gradual start and is well suited for production through-hole work. Four flutes and an H3 thread limit give consistent, on-tolerance threads in a Class 3/3B fit application.

This tap is used in general metalworking and machining applications where through-holes require a 5/8-11 UNC internal thread. Typical install scenarios include structural steel fabrication, machinery repair, fixture building, and production machining of ferrous alloys and stainless steel. The cobalt HSS-E construction handles work-hardening materials better than standard HSS taps. Right-hand cut only. Not designed for blind-hole tapping where chip evacuation forward is not possible.

Key Features

• HSS-E cobalt construction resists heat and wear in hard and work-hardening materials
• Spiral point geometry pushes chips forward, keeping flutes clear in through-hole applications
• Plug chamfer (3-5 lead threads) for progressive thread engagement and controlled start
• H3 thread limit with Class 3/3B fit for close-tolerance threading
• Oxide finish provides mild lubricity and corrosion resistance during storage and use
• Right-hand thread direction, no coolant-through requirement

Compatibility

Designed for through-hole tapping of 5/8-11 UNC threads. Compatible with standard tapping chucks, CNC rigid-tap holders, and tapping heads accepting a 0.480-inch shank diameter.

Installation Notes

Installation and use should be performed by a qualified machinist or tool-and-die professional. Always secure the workpiece fully before tapping and confirm the pre-drilled hole diameter matches the recommended tap drill size for 5/8-11 UNC. Use appropriate cutting fluid for the workpiece material to extend tool life and maintain thread quality. Do not reverse a spiral point tap into a blind hole — this tap is intended for through-hole applications only.