Osg 1650510608 Spiral Flute Tap 1/4-20 Unc Bottoming

Product Description

The OSG 1650510608 is a spiral flute tap designed for cutting 1/4-20 UNC internal threads in a wide range of ferrous and non-ferrous materials. Built from powdered metal with a V coating, this tap delivers consistent thread quality and extended tool life in demanding shop and field applications. The bottoming chamfer allows threading to the bottom of blind holes where standard taper or plug taps cannot reach. With a 45-degree helix angle and right-hand flute direction, this tap efficiently evacuates chips upward out of the hole during the cut, reducing the risk of chip packing in blind-hole applications. It is sized for use in standard tap handles and CNC tapping cycles.

This tap is suited for threading operations in alloy steel, aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, medium-carbon steel, stainless steel, and hardened steel. Its bottoming chamfer and spiral flute geometry make it a practical choice for production machining, maintenance repair, and toolroom work where full thread depth in blind holes is required. The 2B class of fit meets standard commercial thread tolerances, and the H3 thread limit suits most general-purpose tapping applications in these material groups.

Key Features

• Bottoming chamfer for threading to the bottom of blind holes
• 45-degree helix angle promotes upward chip evacuation in blind-hole tapping
• V coating on powdered metal body for improved wear resistance and tool life
• H3 thread limit with 2B class of fit for standard commercial thread tolerances
• Right-hand thread and right-hand flute direction for conventional tapping operations
• No coolant-through design — suitable for standard dry or flood-cooled tapping setups

Compatibility

Designed as an OEM-style replacement tap for 1/4-20 UNC bottoming applications across the material types listed in the application paragraph above. Part of OSG Series 16505.

Installation Notes

This tap is installed and driven by a licensed machinist or toolroom technician using a standard tap handle, tapping head, or CNC machine spindle. Ensure the workpiece is securely fixtured and the pilot hole is drilled to the correct tap drill diameter for 1/4-20 UNC before beginning the tapping operation. Apply appropriate cutting fluid for the workpiece material to reduce friction and extend tap life. Do not exceed the recommended tapping depth for the tool or force the tap past resistance, as powdered metal tooling is susceptible to breakage under torsional overload.