Osg 2864408 Thread Forming Tap 2-56 Unc Bottoming Ticn Hss

Product Description

The OSG 2864408 is a thread forming tap in the HY-PRO NRT series, designed for cutting 2-56 UNC internal threads with a 2B class of fit. Unlike cutting taps, thread forming taps displace material rather than cutting it, producing stronger threads with no chips to clear. This bottoming-style tap features a TiCN coating over a high-speed steel body, providing increased surface hardness and lubricity for extended tool life. With a 1.5 to 2 thread chamfer, it is suited for threading close to the bottom of blind holes. Overall length is 1.75 inches, with a shank diameter of 0.141 inches. It is installed by machinists and toolroom technicians on lathes, drill presses, and CNC tapping setups.

This tap is rated for blind hole threading applications in aluminum, cast aluminum, low-carbon steel, and medium-carbon steel. The bottoming chamfer allows the tap to form full threads very close to the bottom of a blind hole, making it a practical choice in tight-clearance assemblies where thread depth is critical. At 56 threads per inch on a No. 2 screw diameter, this tap is commonly used in precision instrument work, electronics enclosures, and small mechanical assemblies requiring fine, high-strength threaded holes.

Key Features

• Thread forming design displaces material for chip-free threading and stronger thread forms
• TiCN coating increases surface hardness and reduces friction for extended tool life
• Bottoming chamfer with 1.5 to 2 thread lead for threading close to the bottom of blind holes
• High-speed steel construction handles a range of ferrous and non-ferrous materials
• Right-hand thread direction, 2B class of fit for standard internal thread tolerance
• No coolant-through design; suitable for conventional tapping setups

Compatibility

Rated for use in aluminum, cast aluminum, low-carbon steel, and medium-carbon steel workpieces. Designed for blind hole threading applications requiring a 2-56 UNC, 2B class of fit internal thread.

Installation Notes

Thread forming taps require a properly sized forming tap drill hole, which is larger than a standard cut-tap drill size — consult the OSG or tooling manufacturer chart for the correct forming drill diameter for 2-56 UNC before use. Secure the workpiece and ensure the tap is started perpendicular to the hole to avoid thread distortion. Apply appropriate tapping fluid for the workpiece material; aluminum and steel each benefit from different lubricants. Follow shop safety procedures and power down any tapping machine before changing or inspecting the tap.