Union Butterfield 1585(UNF) High-Speed Steel Spiral Point Tap

The Union Butterfield 1585(UNC)/1585(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 to create right-hand threads in a range of materials. 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 €œgun tap€) pushes chips ahead of the tool and the straight flutes reduce clogging. Both characteristics make it suitable for threading through holes (extending through the workpiece). Relieved-style design reduces the friction between tap and workpiece for longer tool life.

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 Union Butterfield 1585(UNC) and 1585(UNF) tap series, taps with 1/4€ to 5/16€ nominal diameters are available in two or three flutes, and those with 3/8€ to 3/4€ nominal diameters have three flutes. They are available with a variety of chamfers. These taps conform to ANSI standards and can create threads to a depth 2 ½ times their diameter. They are suitable for the ANSI 3B tolerance class: 3B produces close-tolerance fasteners that resist loosening, as in aerospace applications.

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.