When is it appropriate to use a taper tap for threading?

Using a taper tap for threading is appropriate when the hole is deep enough because a taper tap has a gradual taper that allows for easier entry into the material, making it beneficial for creating threads in deeper holes. This design helps to ensure that the tap can effectively cut the threads without getting stuck, especially as it progresses deeper into the material.

In situations where the hole is shallow, the taper may not be necessary, and one might opt for a straight tap or a different type of tap that is specifically designed for shallower applications. If starting to thread only, using only a taper tap might not be ideal, as starting can often be accomplished with a different type of tap for precision. Lastly, using a taper tap simply because there is no other tap available does not justify its use; the decision should be based on the specific requirements of the threading task at hand rather than on availability.