How to Use Taps & Dies

Screws and bolts are only useful when they have threads. However, you can cross-thread or strip screws and bolts which makes them useless. It is possible to fix or replace the broken or missing threads by using taps and dies. Taps and dies are available in sets, and they are relatively easy to use.

If the threads on a screw or bolt are crossed, you can repair them using a circle die. Find the die that fits perfectly. Screw the die on the threads. You may need to slowly add drops of oil periodically. Turn the die back one turn if it becomes too tight before you continue. Repeat this as necessary until you finish. To repair threads on an insert or nut, you must find the right size tap. Add some oil to the threads and turn the tap through the nut or insert.

When attempting to create threads on a bar, you need a die that is one size smaller than the bar. Place a few drops of oil on the die and screw it slowly onto the bar, and make sure that you turn the die carefully. The die will create threads on the bar as it rotates. When you need to create threads for an insert, you will need to choose a tap. Take a tap from the set that will fit snuggly into the insert. Before using the tap, place oil on it. Make sure that the tap is perfectly straight and level before you begin screwing it in making sure to keep it straight while you turn it.

In order to restore threads that have been stripped from a screw or a bolt, you need to basically make new threads. Treat the bolt or screw like a bar or an insert without threads. Choose a die that is one size too small or an extremely snug tap. Drop oil on the screw or bolt, and line up the die or tap carefully. Keep the tool straight and twist the die or tap carefully. The threads will be off if the tools are not kept straight and even.