Emuge BU456011.5611 Cobalt Sti Tap 4-40 Unc 3 Flute

Product Description

The EMUGE BU456011.5611 is a cobalt spiral flute STI tap designed for cutting 4-40 UNC threads in titanium and other difficult-to-machine materials. Part of the Rekord D-Ti series, this tap features a 3-flute right-hand spiral configuration with a 15-degree helix angle, which helps evacuate chips efficiently in deep or blind hole applications. The modified bottoming chamfer allows threading closer to the bottom of a hole than a standard plug chamfer. A nitride/oxide surface finish adds wear resistance and reduces galling. Overall length is 2.205 inches, shank diameter is 0.141 inches, and thread length is 0.472 inches. Class of fit is 3BX, appropriate for STI (screw thread insert) thread form production.

This tap is intended for use in precision machining environments where STI threaded inserts are required. The 4-40 UNC thread size and cobalt construction make it well suited for aerospace, medical device, and industrial component work involving titanium alloys and similarly hard or work-hardening materials. It is designed for use with spiral flute tapping operations on CNC machining centers or rigid tapping setups where controlled chip evacuation is critical. The Rekord D-Ti series designation indicates it is specifically engineered for titanium material applications where tap life and thread quality are primary concerns.

Key Features

• 4-40 UNC thread form with 40 threads per inch for fine-pitch STI applications
• Cobalt construction provides hardness and heat resistance in titanium and tough alloys
• 3-flute right-hand spiral design promotes upward chip evacuation in blind holes
• 15-degree helix angle balances cutting action and chip flow in harder materials
• Modified bottoming chamfer allows threading nearer to hole bottom compared to plug style
• Nitride/oxide finish reduces friction and extends tool life in abrasive materials

Compatibility

Designed for STI thread insert production in titanium and comparable difficult-to-machine materials. Part of the EMUGE Rekord D-Ti series, optimized for 4-40 UNC STI thread applications with a 3BX class of fit.

Installation Notes

Installation and use should be performed by qualified machinists familiar with tapping operations on CNC or manual equipment. Always ensure the workpiece is securely fixtured and the spindle is properly aligned before tapping. Use a cutting fluid or tapping compound rated for titanium when running this tap to prevent galling and premature wear. Do not back-tap or force the tool if resistance is felt, as cobalt tooling can fracture under lateral stress.