Westward 5TWD1 Spiral Point Tap 1/4"-20 UNC 2 Flutes Bright

What the tap is for

The Westward 5TWD1 is a spiral point tap designed to cut 1/4"-20 UNC threads in through-holes. It suits machinists and maintenance technicians who need to produce Class 3B internal threads in steel or similar materials. The H3 thread limit provides a standard fit for general-purpose fastening applications. Bright high-speed steel construction resists wear during repeated use.

Installation and common issues

The plug chamfer allows the tap to start easily in a correctly drilled hole, while the spiral point pushes chips ahead of the flutes to reduce clogging. Two flutes provide adequate chip space for this thread size. Problems usually arise when the drill size is wrong, the workpiece material is too hard for uncoated HSS, or cutting fluid is omitted, leading to premature wear or broken flutes.

Limits of the UNC interface

The 1/4"-20 UNC standard defines a coarse pitch that is not interchangeable with fine-pitch or metric threads. Class 3B tolerance leaves minimal allowance for plating or coating buildup on the finished fastener. Uncoated high-speed steel loses hardness at elevated temperatures, so the tap is unsuitable for high-speed production tapping or hardened alloys without appropriate cooling and speed reduction.