Guhring 9039400028450 Thread Forming Tap 4-40 Unc Tin

Product Description

The GUHRING 9039400028450 is a thread forming tap designed for creating 4-40 UNC internal threads without cutting chips. It operates by displacing material rather than removing it, producing stronger threads with better surface finish than cut taps. Built from High-Speed Steel-E-CO (cobalt-enhanced HSS) and coated with Titanium Nitride (TiN) for extended tool life, this tap carries a modified bottoming chamfer with 2-3 chamfered threads for threading close to the bottom of a blind hole. Overall length is 1.882 inches with a thread limit of H4/H5. It is sized for use in machining operations, toolroom work, and production threading applications by machinists and maintenance technicians.

This tap is suited for blind hole and through-hole threading in a range of workpiece materials including steel, stainless steel, cast iron, and non-ferrous metals. The modified bottoming chamfer allows threading closer to the bottom of a blind hole than a standard bottoming tap while still providing adequate lead-in. With a tapping depth of 0.709 inches and a thread length of 0.433 inches, it fits typical small-fastener applications in light fabrication, electronics enclosures, instrument panels, and precision assemblies. It belongs to the Guhring Series 3940 forming tap line.

Key Features

• Thread forming (chipless) design produces stronger threads by cold-working the material rather than cutting
• High-Speed Steel-E-CO (cobalt) construction improves heat and wear resistance over standard HSS
• Titanium Nitride (TiN) coating extends tool life and reduces friction during tapping
• Modified bottoming chamfer (2-3 threads) enables threading close to the bottom of blind holes
• 4 oil grooves support lubrication flow during the forming process
• Right-hand thread direction, Class of Fit 2BX, Thread Limit H4/H5

Compatibility

Designed for 4-40 UNC thread forming in steel, stainless steel, cast iron, and non-ferrous metals. Suitable for both blind hole and through-hole applications where a chipless thread form is required.

Installation Notes

Thread forming taps require a correctly sized forming tap pilot hole, which is larger than a standard cut tap drill size — consult the appropriate forming tap drill chart for the specific material before use. Use a tapping fluid or cutting oil rated for the workpiece material to prevent galling, particularly in stainless steel. Secure the workpiece firmly and use a calibrated torque-controlled tapping arm or CNC rigid tapping cycle to avoid tap breakage in small diameters. This tool should be installed and operated by qualified machinists or maintenance technicians familiar with threading operations.