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Drilling – type of drilling machine
Drilling is the a commonly used way of making round holes. Drilling involves using a round tool which cuts on the end. This is often called a drill bit. It is also possible to make a hole by cutting a ring of metal out of a sheet. This is commonly called trepanning
Drilling is very quick and easy to do and can be done with very simple equipment. But the hole produced is often not very accurate in size, not necessarily straight and does not have a very good finish. Where hole need to be accurate they need to be finished by reaming or boring.
Machines that can be used for drilling
Holes can be drilled using devices as simple as a hand drill or an electric hand drill. These are useful where the workpiece is so big it cannot be moved. This would happen if a hole needed to be drilled in, for example, the milling machine.
Apart from these odd cases it might be thought most drilling problems would be solved by means of a pillar drill. This would certainly be used for the largest number of holes but for accuracy it is not the first choice.
Where holes have to be drilled accurately spaced apart then the first choice has to be the milling machine. This is especially true if it is fitted with DRO’s. If the milling machine is fitted with a quill feed then it is quite useful for run of the mill holes.
Where holes have to be made that have to be concentric with some other round surfaces then the first choice will usually be the lathe. The lathe is also very useful when it is necessary to drill very long holes.