Osg 1195101 Straight Flute Tap 1/4-20 Unc Plug Hss

Product Description

The OSG 1195101 is a straight flute tap designed for cutting internal threads in a wide range of ferrous and non-ferrous metals. It produces a 1/4-20 UNC thread form with a right-hand thread direction and carries a 3B class of fit, making it suitable for standard-tolerance threaded assemblies. The plug chamfer configuration — typically 3 to 5 threads of lead — allows it to start threads in through-holes and sufficiently deep blind holes. Constructed from high-speed steel with an oxide coating, this tap provides adequate wear resistance and lubricity for production and maintenance threading operations. It is suited for use by machinists, maintenance technicians, and trade professionals working with hand or machine tapping setups.

This tap is appropriate for threading operations in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. Its 2-flute straight flute geometry is well matched to shorter chipping materials and through-hole applications. With an overall length of 2.5 inches and a thread length of approximately 0.85 inches, it fits standard tap holders and driver chucks used in drill press, CNC, or hand-tapping workflows. The H3 thread limit designation indicates a controlled oversize tolerance suitable for use with standard tapping lubricants and coated fasteners.

Key Features

• 1/4-20 UNC thread form with right-hand thread direction and 3B class of fit
• Plug chamfer provides 3-5 threads of lead for reliable thread starts in through-holes and deep blind holes
• High-speed steel construction offers durability across a broad range of workpiece materials
• Oxide coating improves lubricity and reduces galling during the tapping process
• H3 thread limit for consistent tolerance control in standard-fit assemblies
• 2-flute straight flute design suited for short-chipping materials including cast iron and aluminum

Compatibility

Compatible with material applications including aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. Fits standard 1/4-20 UNC tap holders and T-handle drivers used in hand and machine tapping setups.

Installation Notes

This tap should be installed in a properly sized tap holder or chuck with the workpiece secured before threading begins. Always apply an appropriate cutting fluid or tapping oil matched to the workpiece material to extend tool life and improve thread finish. For machine tapping, verify that spindle speed and feed rate are set appropriately for the material and tap size before engaging the cut. Inspect the tap for wear or chipping before each use and replace if thread form quality degrades.