Osg 1233400 Spiral Point Tap 5/8-18 Unf Hss Bright

Product Description

The OSG 1233400 is a spiral point tap designed for cutting internal 5/8-18 UNF threads in through-hole applications. Built from high-speed steel (HSS) with a bright finish, it features a plug chamfer and three flutes configured to push chips forward ahead of the cutting zone, keeping the flutes clear during production tapping. The H3 thread limit holds a 3B class of fit, making it suitable for standard tolerance threaded assemblies. Overall length is 3.813 inches with a thread length of 1.813 inches and a shank diameter of 0.48 inches. This tap is intended for use by machinists, maintenance technicians, and metalworking professionals.

The OSG 1233400 is rated for use in a broad range of materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. It is well suited for production environments where through-hole tapping is performed on CNC machining centers, drill presses, or tapping machines. The right-hand thread direction and plug chamfer make it a standard choice for general-purpose tapping operations where chip ejection forward through the hole is practical and preferred.

Key Features

• 5/8-18 UNF thread form with H3 thread limit for 3B class of fit
• Spiral point geometry pushes chips forward, reducing clogging in through-hole applications
• High-speed steel construction provides wear resistance across a wide range of workpiece materials
• Bright finish with no coolant-through — suitable for standard cutting fluid application
• Plug chamfer provides gradual thread engagement for controlled cutting action
• Right-hand cut, non-interrupted thread form, no oversize

Compatibility

Designed for through-hole tapping in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel workpieces requiring a 5/8-18 UNF internal thread to a 3B class of fit.

Installation Notes

Installation should be performed by qualified machinists or maintenance technicians following standard tapping procedures. Secure the workpiece fully before tapping and ensure the tap is properly aligned with the drilled pilot hole to avoid tap breakage or thread damage. Apply appropriate cutting fluid for the workpiece material and do not force the tap if resistance increases unexpectedly. Reverse the tap periodically during manual operations to break chips if needed, though the spiral point geometry is optimized for forward chip ejection in through-hole work.