Osg 1400127200 Thread Forming Tap 1/4-20 Unc Plug Cobalt

Product Description

The OSG 1400127200 is a thread forming tap in the HY-PRO NRT series, designed for cold-forming internal threads without cutting or producing chips. Built from cobalt high-speed steel with a bright finish, this plug-chamfer tap produces 1/4-20 UNC right-hand threads in through-hole applications. It carries an H5 thread limit for close-tolerance work and has an overall length of 2.5 inches with a thread length of 0.594 inches and a tapping depth of 0.933 inches. Licensed machinists and tool-and-die technicians are the primary installers. The cobalt construction handles elevated heat generated during form tapping, making it appropriate for a wide range of ferrous and non-ferrous workpiece materials.

This tap is suited for through-hole threading operations in production machining, maintenance, and repair environments. It performs across a broad material range including alloy steel, carbon steel, die steel, hardened steel, stainless steel, and aluminum. The plug chamfer with 4 to 4.5 chamfered threads allows the tap to start easily in a pre-drilled hole and is appropriate for through-hole conditions where the tap can pass fully through the workpiece. It is not designed for blind-hole applications where a bottoming chamfer would be required.

Key Features

• Thread forming design displaces material rather than cutting, producing stronger threads and eliminating chips
• Cobalt high-speed steel construction resists heat and wear during high-speed tapping
• H5 thread limit for close-tolerance 1/4-20 UNC thread production
• Plug chamfer with 4 to 4.5 chamfered threads for reliable through-hole starting
• Right-hand thread direction, compatible with standard drill press and CNC tapping cycles
• Bright finish with no coolant-through feature; suitable for use with external cutting fluid application

Compatibility

Designed for through-hole threading of 1/4-20 UNC right-hand threads in alloy steel, carbon steel, die steel, hardened steel, stainless steel, and aluminum workpieces. Material application codes P and N apply per OSG classification.

Installation Notes

Thread forming taps require a specific forming tap drill size, which is larger than the drill size used for cut taps at the same thread designation - confirm the correct drill diameter before use. Secure the workpiece fully before tapping and apply a suitable tapping fluid or cutting oil to the tap and hole to reduce friction and extend tool life. Use a calibrated torque arm or CNC tapping cycle with a floating holder to avoid tap breakage. Inspect the tap for wear or chipping before each use; a worn form tap can gall or seize in the hole.