Osg 1733708 Spiral Flute Tap 5/8-18 Unf 4 Flute Hss

Product Description

The OSG 1733708 is a spiral flute tap designed to cut 5/8-18 UNF internal threads in ferrous materials. It features a 45-degree helix angle and a modified bottoming chamfer, making it well suited for threading blind holes where full thread engagement close to the bottom of the bore is required. The tap is manufactured from vanadium high-speed steel with a V finish, providing the wear resistance and edge retention needed when working in stainless steel and carbon steel. It cuts right-hand threads with a right-hand flute and is rated to an H3 thread limit with a 3B class of fit. Installation is handled by qualified machinists and toolroom technicians.

This tap is intended for use in ferrous workpiece materials including stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. It is a standard choice in production machining, maintenance and repair operations, and toolroom environments where close-tolerance 5/8-18 UNF threaded holes are required. The modified bottoming chamfer gives machinists greater usable thread depth in blind-hole applications compared to a standard bottoming tap, reducing secondary operations. At 4 flutes and a 45-degree helix, the spiral design aids chip evacuation out of the hole during the tapping cycle.

Key Features

• 5/8-18 UNF thread form, right-hand thread, H3 thread limit, 3B class of fit
• 45-degree helix angle promotes upward chip evacuation for cleaner blind-hole threading
• Modified bottoming chamfer allows threading closer to the bottom of a blind bore
• Vanadium high-speed steel construction with V finish for extended tool life in steel alloys
• 4-flute right-hand spiral design for rigidity and consistent thread quality
• No coolant-through feature; compatible with flood or brush-applied cutting fluid

Compatibility

Rated for use in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. Designed as an OSG Series 303 spiral flute tap for standard 5/8-18 UNF threaded hole applications.

Installation Notes

This tap is installed and operated by machinists using a tapping head, CNC machine, or manual tap wrench with appropriate torque control. Always drill the correct tap drill diameter and deburr the entry chamfer before tapping. Apply a suitable cutting fluid for the workpiece material, particularly when threading stainless steel. Secure the workpiece firmly and ensure tap alignment is perpendicular to the work surface to prevent tap breakage and thread distortion.