The Dormer E547 uncoated, high-speed steel pipe tap has straight flutes and a round shank with a square end, and is used to create British Standard Pipe Parallel (BSPP) right-hand threads in a range of materials. British Standard Pipe Parallel, also called the BSP G Series, is a standard thread configuration for parallel, or straight, pipe threads. The straight flutes of this tap are suitable for threading through holes (extending through the workpiece) and blind or bottoming holes (with only one opening).
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 provides 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 Dormer E547 series, taps with nominal diameters of 1/8” to 1” have four flutes, taps with nominal diameters of 1-1/4” to 2-1/2“ have six flutes, and taps with a nominal diameter of 3” have eight flutes. In this series all taps come with a variety of chamfers. This tool conforms to ISO 2284 standards and can create threads to a depth one-and-a-half times its diameter. It is suitable for normal pipe thread tolerance.
Taps produce internal threads in previously formed holes and can be used in machines (such as drill presses) or with hand tools. Common types of taps include hand taps, spiral point taps, spiral flute taps, thread forming taps, and pipe taps. Hand taps (straight-flute taps) collect chips in the straight flutes of the tool; spiral point taps push chips through holes ahead of the tool; and spiral flute taps pull chips back from the tip of the tool, up and out the hole. Thread forming taps, also known as cold forming taps, press rather than cut to create threads in a drilled hole, and no chips are created. Pipe taps create threads in pipes and pipe fittings. Each thread type designates a thread profile and each type is identified with an abbreviation. In the U.S. and Canada, the Unified Thread Standard is the dominant thread type, including UNC (Unified Coarse), UNF (Unified Fine), and NPT (National Pipe Taper) threads, among others.
Dormer Pramet manufactures cutting tools under the following brands: Precision Twist Drill, Dormer, Union Butterfield and Pramet. The company has locations around the world, and provides tools adhering to ANSI, NAS, and DIN standards.