Tap and die tools are tools used to cut and make new threads on screws, bolts and nuts. The strength of a screw depends primarily on the composition of its metal and the threading on its body. While the metal determines the strength of the whole unit, its threading determines the strength of its fastening which is the primary purpose of the screw.
The threading strength is determined by the lead, pitch, start and diameter of the threading, which can be adjusted and modified using tap and die tools. While these two usually go together, they have different applications. The tap is used to create threading on the female half of the pair which is the nut in a process called tapping. These can also be used on other supplies that require threading such as the case of pipe taps. On the other hand, the die is used to create threading on the male half of the pair which can be the screw or the bolt in a process called threading. Machinists commonly use these tools in their metal work, although some hobbyists may also require such tools for specialized threading needs. Tap and die tools can also be used to modify or enhance threading that is already in place in a process called chasing.
The tap is to create threading on the inner side of the circle. This produces “female” threading in nuts, pipes and other supplies. There are three basic types of taps used in tapping. The first is the taper tap. This type of tap is typically used to start the tapping process or dig into material that is very hard to cut. These taps have a greater angle for its taper and a greater number of tapered threads. This allows it to cut slowly and gradually. The second type of tap is the intermediate tap or plug tap. These taps are the most common type and are used to align threading throughout the tapping process. They may also be used to start the process just like the taper taps. The third basic tap is the bottom tap. These are usually used to finish the job or bottom out the threading. These have a low number of tapered threads and cannot start the tapping process on their own. A die, on the other hand, creates threading on the outer side of the circle, usually along a cylinder such as the length of the screw or bolt. These are secured with a chamfer and can be adjusted as the length of the screw or bolt moves in order to accommodate changes in diameter. Tap and die tools are usually sold together in tap and die sets, with varying taps and dies to accommodate different threading needs.
There are two ways to create threading on metals. First is with the use of machines. These machines include bench, pillar and radial drilling machines, as well as lathes and milling machines. Machine threading is usually found in big machine factories where there is a constant need for large quantities of screws, bolts and nuts. This method is generally more efficient but may also be very costly when improperly done, resulting in large numbers of threaded products that have to be redone. The second option is the thread metals with the use of hand tapping, of threading by hand with the use of tools. This process usually involves the use of fixtures onto which the metal is secured with the tapping tools are used to create the threading. This process is very tedious and energy-intensive and can only be found when there is a need for unusual specifications for the threading, such as in model-building hobbyists and the like.
Tap and die tools have come a long way since they were first used to create threading for wooden screws. These days, tap and die tool sets such as the Metric Tap and Die set feature machine taps that can endure high speed and high volume jobs while still maintaining their efficiency. Most taps are now made from carbide for higher quality tapping. These carbide cutting tools offer a great combination of strength and heat resistance that makes them ideal for machine shops and factories. Tap and die tools have their niche in metal work and can greatly enhance the effectiveness and longevity of fasteners such as bolt, screws and nuts.