Guhring 9039430028450 Thread Forming Tap 4-40 Unc

Product Description

The GUHRING 9039430028450 is a thread forming tap designed for cutting 4-40 UNC internal threads in a range of metallic workpiece materials. Built from High-Speed Steel-E-CO (cobalt-grade HSS) and finished with a TiCN coating, this tap offers improved wear resistance and heat tolerance compared to uncoated alternatives. The modified bottoming chamfer, with 2-3 chamfered threads, allows threading close to the bottom of a blind hole while still enabling through-hole work. At 1.882 inches overall length, this is a compact tap suited to small-diameter, fine-pitch threading tasks in tight tolerances. It is installed by machinists and maintenance technicians working in precision metalworking, toolroom, and production environments.

This tap is rated for use in steel, stainless steel, cast iron, and non-ferrous metals, covering material application codes P, M, K, and N. It suits both blind hole and through-hole threading applications. The 4-40 UNC thread designation and 2BX class of fit make it appropriate for close-tolerance fastener threads in light mechanical assemblies, instrument hardware, and electrical panel components. The tapping depth reaches 0.709 inches, and the thread length is 0.433 inches, supporting controlled engagement in shallow and moderate-depth holes alike.

Key Features

• 4-40 UNC thread form, 2BX class of fit with H4/H5 thread limit for close-tolerance applications
• Cobalt-grade High-Speed Steel-E-CO construction for elevated heat and wear resistance
• TiCN coating reduces friction and extends tool life in ferrous and non-ferrous materials
• Modified bottoming chamfer (2-3P) allows threading near the base of blind holes
• 4 oil grooves support lubrication distribution during the forming process
• Right-hand thread direction, no coolant-through requirement

Compatibility

Designed for blind hole and through-hole threading operations in steel, stainless steel, cast iron, and non-ferrous metals. Part of GUHRING Series 3943.

Installation Notes

Thread forming taps are installed by machinists using a tapping head, CNC spindle, or hand tap wrench with appropriate torque control. Always ensure the pilot hole diameter matches the recommended forming tap drill size for the 4-40 UNC thread to avoid tap breakage. Apply cutting or tapping fluid suited to the workpiece material before and during the tapping operation. Secure the workpiece completely before engaging the tap, and reverse direction periodically during hand tapping to clear any material buildup.