Osg 1065800 Straight Flute Bottoming Tap 3-48 Unc Hss

Product Description

The OSG 1065800 is a straight flute bottoming tap designed to cut internal threads in drilled holes where thread engagement must extend close to the bottom. With a 3-48 UNC thread profile, 2 flutes, and a high-speed steel construction in a bright uncoated finish, this tap delivers clean, accurate threads in a range of ferrous and non-ferrous materials. The bottoming chamfer provides minimal lead-in, making it ideal for blind holes with tight depth requirements. Overall length is 1-13/16 inches with a thread length of 1/2 inch. Class of fit is 2B with an H2 thread limit, suitable for general-purpose threaded assemblies.

This tap is used in production and maintenance machining applications where small-diameter, fine-thread bottoming work is required. It is suited for manually operated or machine-tapping operations in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The 3-48 UNC size is commonly found in instrument enclosures, small fastener assemblies, and precision mechanical components. Machinists, toolroom technicians, and maintenance mechanics working with machine frames, electronics enclosures, and small mechanical assemblies will find this tap appropriate for their operations.

Key Features

• Bottoming chamfer allows threading to within a few threads of the hole bottom in blind-hole applications
• High-speed steel construction provides durability across a range of workpiece materials including cast iron and carbon steels
• Bright uncoated finish suited for use with standard cutting fluids and oils
• 2B class of fit and H2 thread limit ensure compatibility with standard UNC fastener tolerances
• Right-hand thread direction for use with standard tapping equipment
• 2-flute straight flute geometry promotes chip clearance in through-hole and controlled blind-hole tapping

Compatibility

Designed as an OEM-style replacement or direct-use straight flute bottoming tap for 3-48 UNC threaded holes in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces.

Installation Notes

This tap is installed by qualified machinists or maintenance technicians using a tap wrench, tapping head, or CNC tapping cycle with appropriate speed and feed for the workpiece material. Secure the workpiece before tapping and apply cutting fluid appropriate for the base material to extend tool life and improve thread quality. Do not force the tap if resistance increases unexpectedly, as breakage of small-diameter taps is common when feeds are excessive or the hole is undersized. Verify the correct tap drill size is used for the 3-48 UNC thread form before beginning the tapping operation.