Westward Alloy Steel Tap 45N158 The Westward 45N158 is a sturdy alloy steel tap designed to thread internal components of various materials precisely. Smooth chip removal is made possible by its straight flute design, and long-lasting use in general machining and maintenance duties is guaranteed by its robust construction. Professionals who require consistent threading performance will find it suitable since it is precise and dependable. Material / Alloy Steel Thread Size / 1/4-20 UNC