Osg 1400127901 Thread Forming Tap 1/4-28 Unf Bottoming Cobalt

Product Description

The OSG 1400127901 is a thread forming tap in the HY-PRO NRT series, designed for cold-forming internal threads in a range of metals without cutting or removing material. Built from cobalt high-speed steel with a steam oxide coating, it delivers increased hardness and heat resistance for demanding tapping applications. The bottoming chamfer style with 1 to 1.5 chamfered threads allows threading close to the bottom of blind holes. With an overall length of 2.5 inches and a thread length of 0.594 inches, this tap is sized for 1/4-28 UNF right-hand threads. It is installed using a standard tap wrench or machine holder by machinists and tooling professionals in shop and field environments.

This tap is suited for blind hole threading operations across a broad range of workpiece materials including alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel. The thread forming process displaces rather than cuts material, which produces stronger threads with better surface finish, making it a common choice for production and precision work in these material groups. The H5 thread limit ensures dimensional control for close-tolerance 1/4-28 UNF applications.

Key Features

• Cobalt high-speed steel construction for improved hardness and heat resistance
• Steam oxide coating reduces friction and improves lubrication retention during tapping
• Bottoming chamfer with 1 to 1.5 chamfered threads for threading deep into blind holes
• Thread forming design displaces material rather than cutting, producing stronger formed threads
• H5 thread limit for consistent, close-tolerance 1/4-28 UNF thread production
• Compatible with alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel

Compatibility

Designed for blind hole threading in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel workpieces. Material application codes P and N apply. Suitable for use in standard 1/4-28 UNF tapping applications requiring a bottoming chamfer profile.

Installation Notes

This tap is installed by machinists or tooling technicians using a properly sized tap wrench, tapping head, or CNC machine holder aligned to the bore axis. Always apply appropriate tapping fluid or cutting oil for the workpiece material to prevent galling and extend tool life. Ensure the tap is started straight to avoid thread misalignment or tap breakage. Thread forming taps require a properly sized forming tap drill hole, which differs from a standard cut tap drill size — consult a forming tap drill chart for the correct pilot hole diameter before use.