Accupro T1640603 Spiral Point Tap 9/16-12 Cobalt

Product Description

The ACCUPRO T1640603 is a spiral point tap designed for cutting right-hand internal threads in through-hole applications. Built from HSS-E cobalt steel with an oxide finish, this tap handles tough materials including stainless steel, alloy steel, and high-temperature alloys where standard HSS taps wear prematurely. The 9/16-12 thread size, 3-flute configuration, and plug chamfer make it a workhorse choice for production and maintenance tapping operations. Overall length is 3.5945 inches with a thread length of 1.181 inches, and the shank diameter measures 0.4290 inches. It carries a Thread Limit of H3 and a Class of Fit of 3/3B, meeting standard tolerance requirements for most fastener applications.

This tap is suited for machine tapping in through-hole setups in metalworking environments — job shops, maintenance and repair operations, and production machining. The spiral point geometry pushes chips forward ahead of the tap rather than backing them out, making it well-suited for automated tapping cycles on drill presses, CNC machining centers, and tapping heads. It is not designed for blind-hole applications where chip evacuation forward is not possible. No coolant-through capability is present, so external flood or mist coolant should be applied during use to extend tool life.

Key Features

• HSS-E cobalt construction provides increased heat and wear resistance over standard HSS in difficult-to-machine alloys
• Oxide finish improves lubricity and helps resist galling during tapping
• Spiral point geometry pushes chips forward, keeping the flutes clear in through-hole applications
• Plug chamfer (3-5 thread lead) eases entry and distributes cutting load across multiple teeth
• H3 thread limit and 3/3B Class of Fit maintain tight tolerance control for standard unified coarse thread fastener fits
• Right-hand thread direction compatible with standard tapping attachments and CNC rigid tapping cycles

Compatibility

Designed as a standard replacement spiral point tap for through-hole tapping operations requiring a 9/16-12 UNC thread form with H3 tolerance and 3/3B Class of Fit.

Installation Notes

This tap is installed by a machinist or maintenance technician using a tapping chuck, floating tap holder, or rigid tapping spindle. Always ensure the workpiece is securely clamped and the spindle is properly aligned before starting the tapping cycle. Use appropriate cutting fluid for the workpiece material to prevent galling and extend tap life. Follow shop safety practices and applicable OSHA machine guarding requirements when operating tapping equipment.