Guhring 9039840063500 Spiral Flute Tap 1/4-20 Unc Cobalt Tin

Product Description

The GUHRING 9039840063500 is a spiral flute tap designed for blind hole threading in alloyed and unalloyed steel. It cuts a 1/4-20 UNC right-hand thread using a modified bottoming chamfer, which allows threading closer to the bottom of a blind hole than a standard taper or plug chamfer. The tap is manufactured from cobalt high-speed steel and features a TiN (titanium nitride) coating that reduces friction and extends tool life. With a 40-degree helix angle and fast flute style, it efficiently evacuates chips up and out of the hole during the cut. The H11 thread limit designates a slightly oversize tap, compensating for spring-back in harder materials. Overall length is 2.5 inches and the tool weighs approximately 0.011 pounds.

This tap is intended for use in production and maintenance machining environments where blind hole threading of 1/4-20 UNC fastener holes is required. It is well suited for threading alloyed and unalloyed steel workpieces on CNC machining centers, drill presses, or tapping machines. The modified bottoming chamfer makes it the correct choice when thread depth must extend near the bottom of a blind hole. Coolant-through delivery is not supported, so flood or manual lubrication should be used. It belongs to GUHRING Series 3984.

Key Features

• Modified bottoming chamfer for threading close to the bottom of blind holes
• Cobalt HSS construction provides heat and wear resistance in steel applications
• TiN coating reduces friction and extends tool life between resharpenings
• 40-degree helix angle with fast flute style for efficient chip evacuation in blind holes
• H11 oversize thread limit (0.005 inches oversize) compensates for material spring-back
• Right-hand flute and right-hand thread — standard rotation for conventional tapping setups

Compatibility

Designed for blind hole threading of 1/4-20 UNC threads in alloyed and unalloyed steel. Part of GUHRING Series 3984.

Installation Notes

This tap should be installed by a machinist or tooling professional familiar with tapping operations. Always ensure the spindle and workpiece are properly secured and the machine is set to the correct RPM for the material and tap size before beginning. Use appropriate tapping fluid or cutting oil on the tap and workpiece, as coolant-through delivery is not available on this tool. Do not reverse the tap abruptly under load; use a controlled reversing cycle to back the tap out and clear chips.