A center punch is a tool, usually made of metal, that was created to aid a carpenter with drilling holes. An individual uses a center punch to make a small impression in the piece of wood, plastic, or metal he or she intends to drill a hole into. The mark the punch makes not only helps the person know where to place the end of the drill bit, it also helps to guide the bit, keeping it from slipping out of place.
This tool looks like a cross between a pen and a screwdriver. It has one narrow, pointed end and a wider, flat end. Punches can have flat or rounded sides. Often they have a combination of the two, getting more rounded as they taper toward the point.
Center punches come in many different sizes. Each size corresponds with a particular drill bit size. To use the center punch, a person places the skinny end of the punch against the material intended for drilling, in the exact spot where the hole should be. Then he or she taps the wider end of the center punch with the hammer to create a small divot.
There is a second type of center punch available that accomplishes the same task as a traditional center punch. It is called an automatic center punch. It looks like it has a series of three tubes making up the body of the tool.
While this punch is not electric, as the name might suggest, it does harness the power of a simple machine: the spring. The device has an adjustable end cap at its wider end, which the user can turn to change the center punch's tension. Depending on how it's adjusted, the punch will assert heavier or lighter pressure.
To use this punch, there is no hammer needed. The user simply has to put the point of the punch where he or she would like the divot to appear, and push down on the wider end of the punch. The spring-loaded action will supply all of the force needed to get the job done.
Center punches are available at most hardware stores. The traditional punch is recommended when it's imperative to get a divot of the exact size of the drill bit. Automatic punches are better for less precise jobs, or for creating marks that are not related to drilling.