Understanding the Working Principle of Drilling Machines

A Drilling Machine, also known as a Drill Press, is used to cut holes into or through metal, wood or any other materials which has the ability to withstand high magnitude drilling forces. The drilling machine uses a drilling tool, termed as Drill Bit, which has sharp cutting edges at its point. The drilling machines are categorized in 4 classes- vertical sensitive, upright, radial, and special function. Some of the drill machines which fall under these classes are Upright or Column drilling machine, Sensitive drilling machine, Gang drilling machine, Radial drilling machine, Multi-spindle drilling machine, Vertical drilling machine, Portable drilling machine & many more.


The components of a drilling machine are:

Base: The base acts as a supporting structure for the machine. It is usually made of heavy gray iron, and has slots to give support to the structures that are too large for the table.

Column: The Column is usually round structured and is made from gray cast iron or ductile iron for larger machines, or steel tubing for drill presses which are smaller in size. It gives support to the table and the top half of the drilling machine.

Table: The table is provided to move the work piece along the column. It can also be swiveled around the column in order to reach the intended working position. A large majority of worktables have slots, holes and other structures as accessories for holding the work. Some tables are also capable of being rotated around the horizontal axis.

Head: The spindle, quill, pulleys and the motor are all housed in the head of the drilling machine. The V-belt is attached to the motor driving the pulley located in the front part of the head. This in turn drives the spindle which causes the drill to operate. The speeds on a stepped V-shaped pulley drive can be altered by changing the position of belt.

Angle plates: To support the action by its edge, angle plates are provided. They consist of holes and slots to help clamp the work piece to the table and also holds it together. They also accurately align the work perpendicularly to the surface of table.

Drill jigs: Drill jigs are used when there is a need for multi-tasking. When several holes are required to be made in one particular place. It also helps in locating the work to the favorable drilling position. The drill jig is also used to guide the drill straight through with the help of drill bushings.

radial drilling machine


When the power supply is given, the spindle which is in conjunction with the motor starts to operate. The Radial arm is adjusted according to the type of operation and height of the work piece. The chuck is connected to the spindle and it holds the drill bit in its jaws. The Drill head is adjusted on to the point of application at work piece and a suitable feed is given. The drill bit then drives into the work piece very easily. When the hand wheel is rotated, the pinion which is attached to the rack also rotates which converts the rotary motion to the linear motion. This driving mechanism is called as Rack and Pinion mechanism.


The fundamental application of a drilling machine is to create holes of different shapes and size on any work piece. A number of drill machines are available in the market to perform various operations. Hand drills are used for screwing and fastening. Hammer drill is used by carpenters to drill and fix the wooden parts. Cordless drills are useful where electrical supply is not available. Milling cum drilling machine is broadly adopted in the industries where there is a requirement of mixing and grinding of solid and liquid substances. Pillar drill machine (also referred as drill press) is used in commercial applications where there is a requirement of bulk production of drilled materials in various size and shape like metal sheets, plastic, wood, glass, etc. The capacity of drill press depends on numerous factors namely- pillar diameter, spindle nose, spindle travel, spindle speed and electronic motor used in the machine.

Written by Yash Shah

This blog written by Mr. Yash Shah is about machine tools including workshop machinery, wood working machines, sheet metal machinery provided by Bhavya Machine Tools, a leading distributors of machine tools in India.