Osg 1741505 Spiral Point Tap 1/2-20 Unf Tin Hss

Product Description

The OSG 1741505 is a spiral point plug tap designed for threading 1/2-20 UNF internal threads in through-hole applications. Built from Vanadium High Speed Steel (HSS-E) and coated with Titanium Nitride (TiN), it delivers consistent thread quality across a wide range of metals. The plug chamfer initiates cutting gradually, reducing entry force. With a 3B class of fit and H3 thread limit, the 1741505 produces threads within tight tolerance bands suited for precision fastener assemblies. This tap is installed by machinists and maintenance mechanics using a tap wrench, drill press, or CNC tapping cycle.

The 1741505 is suited for through-hole tapping operations in both production and maintenance environments. Its material compatibility covers aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, alloy steel, die steel, stainless steel, and hardened steel. The right-hand thread direction and three-flute geometry make it a practical choice for general-purpose UNF threading in job shop and manufacturing settings. Coolant-through is not supported, so flood or mist coolant applied externally is the standard approach when cutting harder materials.

Key Features

• 1/2-20 UNF thread form with 3B class of fit and H3 thread limit for tight tolerance control
• Vanadium High Speed Steel (HSS-E) construction for improved wear resistance over standard HSS
• TiN coating reduces friction and extends tool life in abrasive and high-carbon materials
• Plug chamfer style for through-hole applications with gradual thread engagement
• Three-flute design balances chip evacuation and cutting stability
• Right-hand thread direction, compatible with standard tapping equipment and CNC cycles

Compatibility

Designed for through-hole tapping of 1/2-20 UNF threads in aluminum, cast iron, low-carbon steel, medium-carbon steel, high-carbon steel, alloy steel, die steel, stainless steel, and hardened steel.

Installation Notes

This tap is installed by qualified machinists or maintenance mechanics. Ensure the workpiece is securely fixtured and the tap is properly aligned before beginning the threading operation. Use an appropriately sized tap drill per UNF drill chart recommendations and apply cutting fluid or coolant externally to prevent galling, especially in stainless or hardened steel. Do not force the tap if resistance increases unexpectedly — back off to clear chips and check for tap wear or misalignment.