The Union Butterfield 1500OV(UNC) uncoated, high-speed steel hand threading tap has straight flutes that are .005”oversized, a plug chamfer, and a round shank with a square end, and is used in a range of materials to create right-hand threads that will be plated or heat-treated after tapping. It is available in ANSI UNC (Unified Coarse) thread standard sizes. The straight flutes are suitable for threading through holes (extending through the workpiece) and blind or bottoming holes (with only one opening). Oversized taps are used to create threads that are slightly undersized to allow for material added by plating or heat-treating after tapping. The plug chamfer eases tapping at the beginning of the hole and helps maintain correct perpendicular alignment with the workpiece for increased tool life.
Right-hand threads are designed to tighten when the 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 makes it suitable for hand or power-driven applications. 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 1500OV(UNC)series, all taps have four flutes and plug chamfers. This tap conforms to ANSI standards and can create threads to a depth 1 ½ times its diameter.
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.
Precision Dormer manufactures cutting tools under the following brands: Precision Twist, Dormer, and Union Butterfield. The company has locations around the world, and provides tools adhering to ANSI, NAS, and DIN standards.