Osg 1214501 Spiral Point Tap 12-28 Unf Bottoming Hss

Product Description

The OSG 1214501 is a spiral point tap designed for cutting 12-28 UNF internal threads in a wide range of metals. Built from high-speed steel with a steam oxide coating, it drives chips forward ahead of the cutting zone, making it well suited for through-hole tapping operations. The bottoming chamfer allows threading close to the bottom of a blind hole when needed. With an H3 thread limit and a 2B/3B class of fit, this tap produces threads within standard tolerance for most fastener applications. Two flutes provide chip clearance and maintain a manageable cutting load in both light and heavy ferrous materials.

This tap is intended for use in machine-tapping applications across production and maintenance environments. The steam oxide finish provides a degree of lubricity and corrosion resistance that extends tool life during dry or minimal-lubrication cutting. It is appropriate for use in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, and hardened steel. Machinists, toolroom technicians, and maintenance mechanics working on threaded fastener installation or repair will find this tap suited to standard CNC, drill press, and tapping arm setups.

Key Features

• 12-28 UNF thread form with H3 thread limit for 2B and 3B class of fit
• Bottoming chamfer for threading near the base of blind holes
• Spiral point geometry pushes chips forward, reducing chip packing in through-hole applications
• High-speed steel construction handles a broad range of ferrous and non-ferrous workpiece materials
• Steam oxide coating improves lubricity and extends tool life
• Right-hand thread direction, non-coolant-through, non-interrupted thread design

Compatibility

Designed for use in any standard tapping setup requiring a 12-28 UNF bottoming tap with a 0.22-inch shank diameter, including CNC machining centers, drill presses, and manual tapping arms configured for that shank size.

Installation Notes

Installation should be performed by a qualified machinist or toolroom technician familiar with tapping feeds and speeds for the workpiece material. Secure the tap in a properly sized tap holder or chuck before operation, and confirm spindle speed is appropriate for the material and tap diameter. Use cutting fluid or tapping compound where possible to extend tool life, even with the oxide coating. Always back the tap out periodically to clear chips when working in deeper holes.