Osg 1123802 Straight Flute Bottoming Tap 5/8-11 Unc

Product Description

The OSG 1123802 is a straight flute bottoming tap designed for cutting internal threads in a wide range of metallic workpiece materials. Built from high-speed steel, this tap produces 5/8-11 UNC right-hand threads to a 3B class of fit with an H3 thread limit, making it well-suited for applications that demand consistent thread tolerance and clean thread form. The bottoming chamfer allows threading close to the bottom of blind holes. Overall length is 3.8125 inches with a thread length of 1.8125 inches. It carries 4 flutes and belongs to OSG Series 101. Machinists and tool-and-die professionals install this tap in manual and CNC machining operations.

This tap is appropriate for production and maintenance machining environments where blind-hole threading is required. Its straight flute geometry works effectively in through-hole and shallow blind-hole applications across a broad range of materials. The bottoming chamfer style makes it the finishing tap in a tapping sequence when full thread depth to the bottom of a blind bore is needed. It is commonly used in job shops, manufacturing facilities, and maintenance repair operations.

Key Features

• Bottoming chamfer for threading to the bottom of blind holes
• 5/8-11 UNC thread form, right-hand direction, 3B class of fit
• H3 thread limit for consistent tolerance control
• 4 straight flutes for chip clearance across a range of workpiece materials
• High-speed steel construction for durability in general machining applications
• No coolant-through requirement, compatible with flood or manual lubrication

Compatibility

Rated for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpiece materials per OSG Series 101 application data.

Installation Notes

This tap is installed by a machinist or toolroom technician using a tap wrench, tapping head, or CNC rigid tapping cycle. Ensure the spindle and workpiece are properly secured and the tap is aligned to the pre-drilled pilot hole before engagement. Apply appropriate cutting fluid for the workpiece material to reduce heat and extend tool life. When tapping blind holes with a bottoming tap, use a taper or plug tap first to establish the thread before finishing with this tool.