Guhring 9043730021840 Spiral Flute Tap 2-56 Unc Bottoming

Product Description

The GUHRING 9043730021840 is a spiral flute tap designed for bottoming applications in blind holes using a 2-56 UNC thread form. Built from high speed steel with a TICN (titanium carbonitride) coating, it delivers extended tool life in hardened steel applications where conventional taps wear quickly. The tap features 3 right-hand flutes with a 15-degree slow helix angle, a 2BX class of fit, and H3/H4 thread limits. Overall length is 1.772 inches. Licensed machinists and toolroom operators working on precision assemblies, instrumentation, or small-fastener blind-hole work are the primary users of this tool.

This tap is suited for blind hole threading in hardened steel at the 2-56 UNC thread size. The bottoming chamfer allows the thread form to be cut close to the bottom of the hole, making it the correct choice when thread engagement depth is critical and through-hole access is not available. It fits standard tap holders and is used in both manual and CNC tapping operations across precision machining, electronics, and instrumentation manufacturing environments.

Key Features

• Bottoming chamfer for threading close to the bottom of blind holes
• TICN coating improves wear resistance in hardened steel applications
• 3 right-hand spiral flutes with 15-degree slow helix angle for controlled chip evacuation
• H3/H4 thread limits with 2BX class of fit for consistent thread quality
• High speed steel construction for toughness in demanding materials
• Shank diameter of 0.141 inches fits standard tap holder collets for this size range

Compatibility

Designed for blind hole threading in hardened steel using the 2-56 UNC thread standard. Compatible with tap holders and collet chucks sized for a 0.141-inch shank diameter. Part of GUHRING Series 4373.

Installation Notes

This tap should be installed by a qualified machinist in a rigid tap holder or CNC tapping head appropriate for the shank diameter. Ensure the workpiece is securely fixtured and the pilot hole diameter and depth are correct for a 2-56 UNC bottoming tap before starting. Use a cutting fluid or tapping compound compatible with hardened steel to protect both the tap and the workpiece. Never back-drive a bottoming tap with excessive force, as the limited chamfer length makes the tool susceptible to breakage if the hole bottom is contacted under load.