man with drill
A hollow drill is a mechanical device that uses hollow cylindrical bits and is used to drill holes in various objects and surfaces. These bits can be made from many different types of strong metals and are available in a wide variety of shapes and sizes. Hollow core bits are used in many industries and for a variety of purposes.
One of the most common types of hollow drill is a paper drill which is made to “drill” holes into stacks of paper. Typical drill bits are poor to use for this application simply because the paper is delicate and they tear rather than drill fine holes. Hollow core bits used in a paper drill are smooth, hollow, and cylindrical with a sharp blade to cut through the paper. This allows paper that has been pushed out of the holes to be easily removed through the drill hole instead of creating a large amount of paper dust. Any number of core drills, typically one to six, but possibly more, can be placed in a row in a hydraulic core drilling press.
Items that need holes, which can be a stack of paper or cardboard, are placed in the desired position under the drill bits. The machine operator will then safely activate the machine to lower the rotating bits and through the objects. Once inserted, the bits return to the vertical position along with the paper that was removed from the holes. As the process repeats, the waste paper is pushed up through the bits and out of the machine into a waste container. A substance such as wax should usually be applied to the bit when it is in use to prevent it from overheating due to friction.
At the opposite end of the spectrum, core bits can also be used to drill holes in hard, dense materials like rock. In this case, the hole in the bit exists for the purpose of pumping liquid, such as water, during drilling to preserve the integrity of the core bit until the desired depth is reached. Normally the purpose of this is to create blast holes for rocks that need to be removed from a large area, but there can be many reasons to drill holes in dense materials.
For science, a hollow drill rod can be used to extract soil sample material for study. The borer is dug out of the ground or ice, for example, and when it’s removed, a scientist can save the sample for study. This is primarily used to study the effects of an area over time, as the sample will represent how the composition of the dirt has changed, possibly even over millions of years.