Osg 1005200108 Straight Flute Tap 1/4-20 Unc Bottoming

Product Description

The OSG 1005200108 is a straight flute machine tap designed for threading 1/4-20 UNC holes in production and maintenance machining environments. Built from powdered metal and finished with a TiCN (Titanium Carbonitride) coating, it delivers improved wear resistance and extended tool life compared to standard high-speed steel taps. The bottoming chamfer allows threading close to the bottom of blind holes. With 4 flutes and an H3 thread limit, this tap is suited for achieving 3B class of fit tolerances in precision threading applications. Overall length is 2.5 inches with a thread length of approximately 0.598 inches.

This tap is rated for use in aluminum and cast iron. The bottoming chamfer style makes it the right choice when full thread depth is needed in blind-hole applications where a plug or taper tap cannot reach the bottom. It is well suited for CNC machining centers, drill presses, and manual tapping operations in job shops, toolrooms, and production lines. The right-hand thread direction covers the vast majority of standard fastener applications.

Key Features

• Bottoming chamfer for threading to the bottom of blind holes
• TiCN coating for increased hardness, lubricity, and wear resistance
• Powdered metal construction for improved toughness over standard HSS
• 4 flutes with H3 thread limit for consistent 3B class of fit tolerances
• Rated for aluminum and cast iron applications
• Right-hand thread, 1/4-20 UNC — matches the most common inch-series fastener standard

Compatibility

Designed for tapping 1/4-20 UNC threads in aluminum and cast iron workpieces. Suitable for use with standard 0.255-inch shank tap holders and collets in CNC and manual tapping setups.

Installation Notes

Secure the workpiece and ensure the tap is properly aligned with the pre-drilled hole before beginning the tapping operation. Use an appropriate cutting fluid or tapping compound for the specific material being threaded — aluminum and cast iron have different lubrication requirements. Inspect the tap for wear or chipping before each use. Do not force a tap that has stalled — back out, clear chips, and re-evaluate before continuing.