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Union Butterfield 1578(UNC) High-Speed Steel Spiral Point Tap, Screw Thread Insert, Uncoated (Bright) Finish, Round Shank with Square End, H3 Tolerance, 1/4"-20 Thread Size
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About Union Butterfield 1578(UNC) High-Speed Steel Spiral
The Union Butterfield 1578(UNC)/1578(UNF) uncoated, high-speed steel spiral point tap has a relieved-style design, straight flutes, and a round shank with a square end, and is used in a range of materials to tap oversized thread that will receive a helical coil wire screw thread insert (STI). It is available in two different ANSI thread specification standards: UNC (Unified Coarse) and UNF (Unified Fine). The spiral point of this tap (sometimes referred to as a “gun tap”) pushes chips ahead of the tool and the straight flutes reduce clogging. Both characteristics make this tool suitable for threading through holes (extending through the workpiece). Relieved-style design reduces the friction between tap and workpiece for reduced tool wear. A screw thread insert is used to replace stripped, damaged, or weakened internal threads. STI taps are oversized so they can tap threads that will receive a helical coil wire STI of the same nominal size and pitch. The plug chamfer distributes cutting to ease tapping at the beginning of the hole and to maintain correct perpendicular alignment with the workpiece. Right-hand threads are designed to tighten when a head or nut is rotated clockwise (the most common threading direction). High-speed steel (HSS) is a common general-purpose steel for cutting tools, and is compatible with a variety of materials. With no coating or surface treatment, this uncoated tool can be used on a broad range of materials and provide an economical alternative to coated tools. The round shank with square end helps to minimize rotation in the tool holder. This tool can be used in machines, such as drill presses or lathes, or with hand tools such as tap wrenches. In the Union Butterfield 1578(UNC) and 1578(UNF) tap series, all taps have two flutes and plug chamfers. This tap conforms to ANSI standards and can create threads to a depth 1 ½ times its diameter. It is suitable for ANSI 2B and 3B tolerance classes: 2B is an average quality fit
