Osg 1761908 Spiral Flute Tap 5/8-18 Unf Modified Bottoming

Product Description

The OSG 1761908 is a spiral flute tap designed for cutting 5/8-18 UNF internal threads in a modified bottoming chamfer configuration. Manufactured from vanadium high-speed steel with a TICN coating, this tap delivers increased wear resistance and reduced friction in demanding materials. The 45-degree helix angle evacuates chips upward and away from the cutting zone, making it well suited to blind-hole applications. Rated to a 3B class of fit with an H3 thread limit, it produces threads within tight tolerance ranges required by precision assemblies. The tap is intended for use by machinists and toolroom professionals on production or job-shop equipment.

This tap is rated for use in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. The modified bottoming chamfer allows threading closer to the bottom of a blind hole than a standard plug or taper chamfer. With a 5/8-18 UNF thread form, it is commonly applied in fastener repair, fixture building, and component manufacturing where a fine unified thread is specified. Right-hand flute direction and right-hand thread orientation are standard for conventional CNC and manual tapping operations.

Key Features

• 5/8-18 UNF thread form with 3B class of fit and H3 thread limit for precision tolerance control
• 45-degree right-hand spiral flute geometry promotes upward chip evacuation in blind holes
• Modified bottoming chamfer allows threading close to the bottom of a blind bore
• Vanadium high-speed steel construction resists heat and wear in ferrous materials
• TICN coating reduces friction and extends tool life in stainless and carbon steel applications
• No coolant-through design; suited for use with external cutting fluid application

Compatibility

Rated for use in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. Part of OSG Series 303.

Installation Notes

This tap is installed and operated by machinists using CNC machining centers, drill presses, or manual tapping equipment. Always ensure the workpiece is securely clamped and the tap is properly aligned before engaging the thread. Apply appropriate cutting fluid for the workpiece material to prevent galling, particularly in stainless steel. Inspect the tap for wear or chipping before each use and replace if cutting edges show damage.