There is hardly a product produced that does not contain one or more holes.The location finish and size of these holes may be critical as in the case of a component for missile or they may be critical as in the case of a component for a missile or they may be holes like those punched in a temnplate for the purpose of hanging it on the wall when not in use. Holes are produced and finished in a number of ways.They are drilled, reamed, bored, punched,ground,flame cut etc... Drilling is by far the most common method. Adrill is a device for ensuring that a hole to be drilled,reamed or tapped in a workpiece will be machined in the proper location. The term jig is used only for devices employed while drilling,reaming or tapping holes.It is not fastened to the machines on which it is used. If the operation includes machining operations like milling,planing,turning,grinding etc. the term fixture is used.