Union Butterfield 1585NR(UNC) High-Speed Steel Spiral Point Tap, Non-Relieved Style, Uncoated (Bright) Finish, Round Shank with Square End, Plug Chamfer, 2 Flute, H3 Tolerance, 1/4"-20 Thread Size

The Union Butterfield 1585NR(UNC)/1585NR(UNF) uncoated, high-speed steel spiral point tap has a non-relieved 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). The non-relieved design of this series has concentric threads without pitch diameter relief. It is recommended for applications requiring close gauging fits and in older equipment that is not sufficiently rigid to accomodate the relieved-style series of spiral pointed taps.

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 1585NR(UNC) and 1585NR(UNF) tap series, taps with 1/4€ to 5/16€ nominal diameters are available with two or three flutes, and those with 3/8€ to 3/4€ nominal diameters all have three flutes. The 1585NR(UNC) taps are available with a variety of chamfers; 1585NR(UNF) taps all have plug chamfers. This tap conforms to ANSI standards and can create threads to a depth 2 ½ times its diameter. It is suitable for ANSI 2B and 3B tolerance classes: 2B is an average quality fit for commercial and industrial fasteners; 3B produces close-tolerance fasteners used for greater resistance to stripping, 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.