Month: January 2019

History of drill machines and its evaluation The invention of drill machine dates back to the Egyptians and Harappans era with the earliest invention of bow drills. With various sources of power like the water wheels, windmills and human effort expanded over many decades came the electric motor during the late nineteenth century. Among the power machineries and motors, the drilling tools were one of them. With the headway of technology the application of drill machine started commercially, industrially and also domestically. It proved great with its versatility and convenience in the metal processing, manufacturing and construction units. Not only of industrial operation, these drilling machines are also equipped with features to serve the medical world, space missions and industries involved in wood working, metal working and masonry. Besides boring holes in the work pieces, the application of drill machine ranges to assignments like countersinking, reaming, tapping, spot facing, counter boring and much more. The drilling machineries come in an array...

Though drilling machine is designed to make straight and accurate holes, it is used for many other operations. Major operations that are carried out on a drilling machine are explained below: (a)Drilling :-  The operation of drilling consists of producing a hole in an object by forcing a rotating drill against it. The same result is carried out in some machines by holding the drill stationary and rotating the work as on the lathe.   (b)Boring :-  It is the operation of enlarging a hole that has already been drilled or bored with a single point tool. It also rectifies the error of drilling, if any. (c)Counter Boring :- It is the operation of enlarging one end of a drilled hole. The enlarged hole is connected to the original one and it is flat at the bottom. It is done to set bolt head and nuts below the surface. (d)Spot Facing :- To finish off a small surface around a drilled hole is known as...