Kennametal 4131976 Thread Forming Tap 1/4-20 Unc Bottoming

Product Description

The KENNAMETAL 4131976 is a thread forming tap designed for creating internal threads without cutting, using plastic deformation to produce stronger thread forms with no chips. Built from Vanadium High Speed Steel (HSS-E) with a bright uncoated finish, this bottoming tap features a 1/4-20 UNC right-hand thread and is engineered for blind hole threading applications. The bottoming chamfer design, with 1.5 to 2 chamfered threads, allows threading close to the bottom of a blind hole. With an overall length of 2.5 inches and a thread length of 0.625 inches, this tap is suited for production machining environments and is typically installed by machinists and toolroom technicians working with non-ferrous metals.

This tap is intended for non-ferrous metal applications, including aluminum, brass, copper, and similar materials where thread forming is preferred over thread cutting. The thread forming process work-hardens the material, resulting in increased thread strength and improved fatigue resistance compared to cut threads. It is well suited for use in CNC machining centers, drill presses, and manual tapping operations in both job shop and production settings where blind hole threading is required.

Key Features

• Thread forming design eliminates chips, reducing the risk of chip packing in blind holes
• Vanadium High Speed Steel (HSS-E) construction provides increased wear resistance and toughness
• Bottoming chamfer (1.5-2P) allows threading to the bottom of blind holes
• H6 thread limit ensures consistent tolerance control for 1/4-20 UNC threads
• Bright uncoated finish suitable for use with cutting fluids on non-ferrous materials
• Right-hand thread direction compatible with standard tapping setups

Compatibility

Designed for blind hole thread forming in non-ferrous metals such as aluminum, brass, and copper using 1/4-20 UNC thread specifications. Compatible with standard tap holders and tapping attachments accepting a 0.255-inch shank diameter with a 0.191-inch square drive.

Installation Notes

Thread forming taps require a properly sized forming tap drill — use the correct pilot hole diameter specified for 1/4-20 UNC thread forming, as it differs from standard cut tap drill sizes. Apply appropriate tapping fluid or cutting oil rated for non-ferrous materials before and during the tapping operation. Ensure the workpiece is securely fixtured and the tap is started perpendicular to the surface to avoid cross-threading or tap breakage. Always power down or de-energize the machine spindle before manually inspecting or repositioning the tap.