Osg 1670100 Straight Flute Tap 12-32 Unef Plug Hss

Product Description

The OSG 1670100 is a straight flute plug tap designed for cutting 12-32 UNEF internal threads in a range of ferrous and non-ferrous materials. Built from high-speed steel with a bright, uncoated finish, this tap delivers consistent thread quality in production and repair applications. The plug chamfer distributes cutting load across the first few threads, making it well-suited for through-hole tapping. With 4 flutes and an H3 thread limit, the 1670100 provides controlled oversize tolerance for plated or close-tolerance threaded assemblies. A licensed machinist, toolmaker, or maintenance technician typically installs this tap in a machine or hand-tapping setup.

This tap is suited for tapping operations in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. The 12-32 UNEF thread form is commonly found in precision instruments, electronics hardware, and mechanical assemblies where a fine thread pitch is required in a No. 12 diameter fastener. The plug chamfer style makes this tap a practical choice for through holes and for starting threads in blind holes when full thread depth is not required at the very bottom of the bore.

Key Features

• 12-32 UNEF thread form with right-hand direction and H3 thread limit for controlled oversize tolerance
• Plug chamfer distributes cutting load across the leading threads for smooth thread entry
• 4 straight flutes for chip evacuation in a range of workpiece materials
• High-speed steel construction provides durability across aluminum, cast iron, and carbon steel grades
• Bright, uncoated finish suited for general-purpose tapping without coating-specific requirements
• No coolant-through design - compatible with standard hand or machine tapping setups

Compatibility

Designed for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. Compatible with standard tap holders, T-handle tap wrenches, and machine tap chucks sized for a 0.22-inch shank diameter. Intended for 12-32 UNEF threaded applications per the OSG 101N series.

Installation Notes

Use a tapping fluid or cutting oil appropriate for the workpiece material to extend tool life and improve thread finish. Ensure the workpiece is securely fixtured and the tap is properly aligned before applying cutting pressure. When tapping blind holes, back the tap out periodically to clear chips from the flutes. Always use the correct drill size for a 12-32 UNEF thread to avoid tap breakage or out-of-tolerance threads.