Osg 1650513008 Spiral Flute Tap 1/2-28 Unf Bottoming

Product Description

The OSG 1650513008 is a spiral flute bottoming tap designed for threading 1/2-28 UNF holes in a wide range of metals. It features a 45-degree helix angle that efficiently evacuates chips upward out of blind holes, reducing the risk of chip packing and thread damage. Built from powdered metal with a V coating, this tap handles demanding materials including stainless steel, hardened steel, cast iron, and aluminum alloys. The bottoming chamfer allows threading close to the bottom of blind holes. It carries a 2B class of fit and an H4 thread limit for controlled tolerance. Machinists, tool-and-die workers, and maintenance technicians typically run this tap on CNC machining centers or manual tapping equipment.

The 1650513008 is suited for production and maintenance tapping applications in ferrous and non-ferrous metals. Its 3-flute spiral configuration performs well in short-chipping materials such as cast iron and medium-carbon steel, as well as in aluminum and alloy steel. The bottoming chamfer makes it the correct choice when thread depth must reach near the floor of a blind hole. At 3.937 inches overall length with a 0.614-inch thread length and 49 mm tapping depth, it fits standard 1/2-inch shank tap holders and is appropriate for both manual and machine tapping operations.

Key Features

• 45-degree helix angle for upward chip evacuation in blind holes
• Bottoming chamfer for threading to near the bottom of blind holes
• Powdered metal construction with V coating for extended tool life in abrasive and hard materials
• H4 thread limit with 2B class of fit for consistent, controlled tolerance threads
• Right-hand flute and right-hand thread direction; compatible with standard tap holders
• Rated for alloy steel, aluminum, cast aluminum, cast iron, hardened steel, high-carbon, medium-carbon, low-carbon, and stainless steel

Compatibility

Designed for use in standard 1/2-inch tap holders and collet systems used on CNC machining centers, drill presses, and manual tapping arms. Suited for 1/2-28 UNF bottoming applications across the listed material types in OSG Series 16505.

Installation Notes

Install in a properly sized tap holder rated for the shank diameter of 0.367 inches before use. Ensure the workpiece is securely fixtured and the spindle speed and feed rate are appropriate for the material being tapped. Apply cutting fluid or tapping compound appropriate for the workpiece material; coolant-through is not available on this tap. Inspect the tap for wear or chipping before each use and replace at first sign of thread quality degradation.