Osg 2492800 Straight Flute Tap 2-56 Unc Plug Hss

Product Description

The OSG 2492800 is a straight flute machine tap designed for cutting 2-56 UNC internal threads in aluminum and cast iron. It features a plug chamfer style, three flutes, and a 2B class of fit with an H2 thread limit, making it suitable for standard through-hole and short blind-hole tapping applications. The tap is manufactured from vanadium high-speed steel and left in a bright, uncoated finish. Overall length is 1.75 inches with a thread length of 0.437 inches. This tap is part of the OSG Series 240 and is used by machinists and maintenance technicians working with small-diameter fastener threads.

This tap is suited for production and maintenance tapping of 2-56 UNC threads in non-ferrous metals such as aluminum and in ferrous materials including cast iron. The plug chamfer provides a gradual thread start with several leading threads tapered, making it appropriate for through holes and moderately deep blind holes. It is commonly used in precision assembly, instrument work, and light mechanical fabrication where small machine screws are the standard fastener.

Key Features

• 2-56 UNC thread form, 56 threads per inch, right-hand thread direction
• Plug chamfer entry for versatile through-hole and shallow blind-hole use
• Vanadium high-speed steel construction for improved wear resistance over standard HSS
• Bright uncoated finish — inspect and resharpen without coating interference
• H2 thread limit and 2B class of fit for standard tolerance thread production
• Three straight flutes — no coolant-through requirement

Compatibility

Designed for tapping 2-56 UNC threads in aluminum and cast iron workpieces. Compatible with standard tap wrenches, T-handle holders, and machine tap holders sized for a 0.141-inch shank diameter.

Installation Notes

This tap is installed and operated by machinists or maintenance technicians using manual tap wrenches or CNC and manual drill press setups. Secure the workpiece before tapping and apply appropriate cutting fluid for the material being threaded, particularly with aluminum. Use a correctly sized pilot hole per UNC tap drill charts for 2-56 threads. Avoid excessive torque on this small-diameter tap to prevent breakage — back off periodically to clear chips when tapping blind holes.