What Is a Tap & Die Set Used For?

A tap is a threaded tool used to thread or re-thread a female screw/bolt hole (nut type) in metals and other solid substances capable of holding a thread (some plastics). A die is the companion threading tool used to thread or re-thread a male screw/bolt that has been damaged or stripped. A damaged hole in metal is commonly called a stripped hole. Cutting a hole with a tap is called tapping. Threading a metal rod is called threading or chasing the rod. Hand taps and dies are intended for manual use.

Using A Tap

Taps are operated by inserting the tap into a T-wrench and then placing the tap in the hole. If the tap is re-threading a stripped hole care should be taken to use the right size and type of tap. Existing threading at the top of the hole should be accessed rather than cut across. Reverse or move the tap counter-clockwise to find the entry point and then move the tap forward and reverse to slowly cut the new thread. By reversing, the new thread is affirmed and debris is cleaned out of the flutes and the new area to be cut isn't crowded.

Cleaning

The hole may need to be cleaned during the tapping process by blowing the hole out with an air gun to remove metal filings. This should also be done when the hole is fully tapped. The biggest problem with hand tapping is keeping the tool aligned perfectly to your surface. If your surface is portable, a stabilizing jig or conical tapping guide can be made to ensure a straight cut.

Using A Die

Dies are mounted into a die holder. This rod-like holder has a central area where dies are tightened into place. Dies, like taps, are used by twisting on the rod in a forward and reverse motion, a working on of the new thread. Often the object or rod being threaded is held in a vise for stability. Depending on the type of tap and die and the type of object being threaded, lubricants are used to facilitate the cutting process.

Function

Dies are used to thread pipes, metal rods, plastic rods and sometimes wood rods. They are a generally inexpensive way to create bolt-like shafts in custom applications when the correct length is not available. They are also useful in making on-the-site repairs as the hand-held tap and dies are small and portable. This is particularly helpful when the object being re-threaded is mounted or fixed in location or is otherwise difficult to access. Taps are often used in automotive type applications when bolt holes have been stripped or when bolts sheer off.

Benefits

A hand tap and die set is a good addition to a well-stocked toolbox for any individual who likes to do home, car, motorcycle or boat repairs. Using the tools are not difficult but they do require patience and careful alignment to work properly. If you invest in a tap and die set then you should consider small wire brushes and thread-cleaning files to clean threads.