Osg 1978200 Straight Flute Tap M30x3.50 Metric Coarse

Product Description

The OSG 1978200 is a straight flute bottoming tap designed for threading M30x3.50 metric coarse threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel with a bright uncoated finish, this tap operates with a right-hand thread direction and is manufactured to a 6H class of fit with a D9 thread limit. It features 4 flutes and a bottoming chamfer, making it well suited for threading blind holes where full thread depth close to the bottom is required. Overall length is 5.4375 inches with a thread length of 2.5625 inches. Licensed machinists, tool and die makers, and maintenance technicians are the primary users of this tap.

The OSG 1978200 is appropriate for use in machining operations involving aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. The bottoming chamfer geometry is ideal for blind hole applications where a spiral flute tap is not preferred and chip evacuation can be managed through the straight flute design. This tap belongs to OSG Series 141 and is sold individually.

Key Features

• Bottoming chamfer for threading close to the bottom of blind holes
• 4 straight flutes for use in a variety of workpiece materials including cast iron and carbon steels
• 6H class of fit with D9 thread limit for standard metric tolerance requirements
• High-speed steel construction provides durability across a broad range of cutting applications
• Bright uncoated finish — no coating interaction with workpiece material
• No coolant-through requirement, compatible with flood or manual lubrication setups

Compatibility

Designed for M30x3.50 metric coarse thread applications in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. Suitable for use in CNC machining centers, drill presses, and manual tapping operations where straight flute tap geometry is appropriate.

Installation Notes

This tap should be installed in a rigid tap holder or floating tap collet appropriate for the shank diameter of 1.021 inches. Always ensure the workpiece is securely fixtured and the spindle is properly aligned before tapping. Use a suitable cutting fluid for the workpiece material to extend tool life and maintain thread quality. Inspect the tap for wear or chipping before each use, particularly when working in harder steels.