Osg 2866600 Thread Forming Tap 3/8-16 Unc Bottoming Hss

Product Description

The OSG 2866600 is a thread forming tap designed for blind hole threading in a range of ferrous and non-ferrous materials. Unlike cutting taps, thread forming taps displace material rather than cut it, producing stronger threads with no chips to clear from the hole. This tap is ground to 3/8-16 UNC with a 2B class of fit and features a bottoming chamfer with 1.5 to 2 chamfered threads, allowing threads to be formed close to the bottom of a blind bore. Manufactured from high speed steel with a bright finish, it measures 2.9380 inches in overall length and is suitable for use with standard tap wrenches or machine tapping setups. It is installed by HVAC technicians, machinists, pipefitters, and general maintenance trades.

This tap is suited for blind hole applications in aluminum, cast aluminum, low-carbon steel, and medium-carbon steel. The bottoming chamfer style makes it the correct choice when full thread depth close to the bottom of a blind hole is required, such as tapped mounting bosses, structural brackets, and enclosure hardware common in HVAC and light fabrication work. The right-hand thread direction aligns with standard fastener convention. A tapping depth of 1.2520 inches supports typical blind hole depths encountered in sheet metal and light structural applications.

Key Features

• Thread forming design displaces material for chip-free blind hole threading and stronger finished threads
• Bottoming chamfer with 1.5 to 2 chamfered threads for maximum thread depth close to the hole bottom
• 3/8-16 UNC thread form with 2B class of fit for standard inch-series fastener compatibility
• High speed steel construction for durability across aluminum and carbon steel workpieces
• Bright finish, no coating — suitable for use with cutting fluid applied at the point of use
• Right-hand thread direction; no coolant-through requirement simplifies setup

Compatibility

Designed for blind hole threading in aluminum, cast aluminum, low-carbon steel, and medium-carbon steel. Material application codes P and N confirm suitability for these material groups. Not recommended for hardened steels or cast iron without confirming workpiece machinability.

Installation Notes

Thread forming taps require a properly sized forming tap drill — the recommended hole diameter for form tapping differs from standard cut-tap drill charts and must be confirmed before use. Apply an appropriate tapping lubricant or cutting fluid before driving the tap. Use a calibrated torque-controlled tapping attachment or hand tap wrench to avoid overloading the tap in harder materials. Power down and lock out any machine tool before installing or removing the tap from the holder.