These standard style taps have straight flutes of a number specified as either standard or optional. Hand taps are for general purpose applications such as production tapping or hand tapping operations. Taper, plug and bottoming styles provide versatility in tough materials, blind and through holes.
Spiral Point Tap
Spiral point taps have the same general physical dimensions as standard hand taps. However, the spiral point tap has the cutting face of the first few threads cut at a predetermined angle relative to the tap’s axis angle to force the evacuation of chips ahead of the cutting action. This feature, plus the excellent shearing action of the flute, make spiral point taps ideal for production tapping of through holes. Typically, this type of tap has a shallower flute passage than conventional taps. This gives the spiral point tap more cross-sectional area, which means great strength, allows higher tapping speeds, and requires less power to drive.
Spiral Fluted Tap
Spiral flute taps feature spiral flute design rather than conventional straight flutes. The spiral fluting feature aids in evacuating chips out of the tapped hole. Spiral flutes are recommended when bridging a gap inside the hole such as a keyway or cross-hole. Commonly available in slow spiral (18-30° helix angle) or fast spiral (45-52° helix angle). Following are recommendations for degree of spiral for various materials:
- High spiral flutes 45° and higher – effective for very ductile materials like aluminum and copper. If used in other materials, they will usually cause the chips to nest because the spiral is too fast and chip area is too small for chip to form correctly.
- Spiral flutes 38° – 42° – recommended for medium to high carbon steels or free machining stainless steels. They form a chip tight enough to easily evacuate. On larger taps, it allows for pitch relief to ease the cutting.
- Spiral flutes 25° – 35° – recommended for free machining, low or leaded steels, free machining bronze or brasses. Spiral flute taps used in brass and tough bronzes normally do not perform well because the small broken chip will not flow up the spiral flute well.
- Spiral flutes 5° – 20° – For tougher materials such as some stainless, titanium or high nickel alloys, a slower spiral is recommended. This allows the chips to be slightly pulled upward but does not weaken the cutting edge as much as higher spirals will.
Interrupted Thread Tap
These taps have an odd number of lands with alternate teeth in the thread helix removed. The removal of every other tooth helps to break the chip and allows a greater supply of lubrication to reach the cutting teeth, reducing the incidence of torn threads. Ideal for tapping non ferrous metals and low carbon steel; as well as use in titanium and high hardness alloys.
Thread Forming Tap (Tru-Flo™)
Thread forming taps are fluteless except as optionally designed with one or more lubrication grooves. The thread form is lobed so there is a finite number of points contacting the work. This tap does not cut, so it is ‘chipless, and consequently will not cause a chip problem. The tool forms the thread by extrusion, thus thread size can be closely maintained. The fluteless design allows high quality threads, faster tapping speeds, higher production, and generates no chips which simplifies tapping of blind bottoming holes (threads can be formed the full depth of the hole).
Combined Drill and Tap (Cost Cutter™)
This high production combined drill and tap tool is specially designed to drill and tap in one pass only. By design, this value-added tool reduces machining operations and subsequent parts handling. The drill end features a split point, and the tool shank and square fit standard tap holders.
ACME Thread App
Acme screw threads were devised to allow rotary and transversing motion on machines; and are also used in jacks, valves, presses and other mechanisms where heavy loads are encountered. Acme taps are characterized by a 29° included angle. Acme taps typically require specialized engineering and design due to the nature and severity of cut required in producing Acme threads.
Tandem ACME Tap
These taps combine the initial roughing cut with the final finishing cut, in one pass, to achieve an acme screw thread. These taps are economical and enhance production levels by saving on the operation of two tools. Since acme thread pitches are generally coarse relative to diameters, these taps are subjected to heavy chip loads. To achieve a high quality acme thread in a cost-effective manner, roughing and finishing operations – in tandem – are recommended
Extension Taps (incl. Nut and Pulley Taps)
Extension taps are made to conventional tap dimensions, except that they have an extended shank to reach inaccessible holes. Thread length, shank diameter, and shank square are made to standard specifications listed in Table 302. Extension taps are available in both hand and spiral point styles, and in small shank style.
The hub portion of pulley parts contain oil cups and set screw holes, most of which cannot be reached with ordinary hand taps. Pulley taps have the same basic thread dimensions as hand taps, but pulley taps differ in that they have a longer shank which is of the same basic major diameter as the threaded portion. When tapping pulley hub holes, the taps are inserted through holes in the rims which are slightly larger than the shanks of the taps. These holes serve as guides or bushings for the taps to assure proper alignment when tapping. Pulley taps can also be used for general tapping in parts where an extra long length is required to reach the holes being tapped.
Nut taps feature a long chamfer which assists in entering the drilled hole, and distributes the cutting action over several teeth. These taps were initially designed for tapping nuts and have a long thread length. The shank diameter is smaller than the tap’s minor diameter to allow the accumulation of several nuts after tapping. Nut taps also feature an extended square length.