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A taper tap to cut a thread on the inside surface of a hole. From a blacksmith in Eynsham, Oxfordshire.
A tap cuts a thread on the inside surface of a hole. This is a 'taper tap', which has a very gradual cutting action and is often used when the material to be tapped is difficult to work, or when the tap has a very narrow diameter and is liable to break. This example was acquired from the blacksmith's forge in Eynsham, Oxfordshire. This type of tap is used by blacksmiths in the making of wedges or woodworking chisel blades.