There are two types of edge finder: single end edge finders and double end edge finders (combination edge finders and centre finders).
Single end edge finders
Single end edge finders consist of an edge finder only. They are used to locate a workpiece in relation to the centreline of a spindle.
Single end edge finders are most commonly used with parts that have straight edges or straight-edged grooves or slots.
Double end edge finders
Double end edge finders, or combination edge finders and centre finders, incorporate two tools in one. Whilst they can be used in the same way as single end edge finders, the conical end of the combination edge finder functions as a centre finder.
This means that the the tool can also be used to locate centre punch marks or holes in a part relative to the spindle of the machine.