Drilling machines, or drill presses, are workshop staples.
You can find different types of drill presses and they come in different sizes. All of them comprise three basic components: the base, column, drill head, and spindle. The remainder of the components may vary slightly, depending on the type of drill press and its intended application.
Below, I will explain the different drill parts and their functions in detail.
10 Main Parts of a Drill Press Explained
The drill press base is generally cast iron since this heavy metal offers stability to the tool, even during heavy operation. Depending on the press’s design and size, this base is mounted on a workbench, a pedestal, or floor. Floor-mounted machines tend to be heavier and are designed for larger workpieces that are generally cumbersome. Bench-mounted machines, in contrast, tend to be smaller and are typically used for smaller workpieces.
The base effectively dampens (or eliminates) vibration during operation when bolted to the floor, thus enhancing the drill press’s accuracy.
2. Column (or Pillar)
The column is mounted on the base in a vertical position. This component is accurately machined since it supports the table on which the workpiece would rest during operation. This table (referred to later) can be moved up or down to suit the work at hand.
The column is the drill press’s backbone, holding all the components together. This component must be sturdy and accurate since the accuracy of any work done using the drill press depends on this largely.
On one side, the drill head houses the sleeve and feed handle, while the electric motor is housed on the opposite side. This configuration forms a counterbalance, optimizing the drill’s weight distribution.
The drill head’s size and shape differ depending on the type of drill. Either the head or the table is always able to move vertically along the column. This adjustability allows for drilling workpieces of various shapes and sizes.
On a radial drilling machine, the drill head can move horizontally to and from the column, guided on a radial arm. This allows for drilling at various distances from the base, rendering the drill press more versatile.
In some drill presses, the head houses equipment to supply cooling liquid to the workpiece. Appropriate use of cooling liquid ensures a high-quality finished product.
The drill spindle is mounted at the top of the column. It fits into the sleeve and holds the chuck, which in turn holds the drill bit. The motor turns the spindle at a controlled speed, which then turns the chuck and cutting tool.
5. Sleeve (or Quill)
The drill sleeve is a hollow steel shaft designed to hold the chuck’s tapered shaft. The sleeve is moved vertically during operation, thus moving the drill bit to and from the workpiece.
The electrical motor is mounted at the top of the column, along with the spindle. This motor drives the drill shaft through power received from the drive belt.
The motor’s size and specifications vary according to the drill press’s size. Large, floor-mounted drill presses are used for larger jobs and typically involve heavier work. To accommodate this, the motor should be larger and more robust. Conversely, smaller, bench-mounted drill presses require smaller motors since the projects involved are generally smaller.
That said, both small and large drill presses can be used for nearly any material, ranging from hard metals and steel to wood and plastic.
Typically, the motor would have a variable speed drive, which can be adjusted using a dial on the drill press. This allows the operator to set the drill speed to suit the workpiece’s size and material. The appropriate drill speed varies depending on the material drilled.
7. Drive Belt & Pulley
The motor supplies power to the drive belt, which is, in turn, connected to the pulley on the spindle. As the drive belt rotates, the spindle rotates, culminating in the drill bit spinning at high speed that enables it to penetrate into the workpiece.
Usually stepped pulleys are used to amplify the speed ratio. This belt could be a flat belt or a V-belt, depending on the machine’s configuration.
V-belts wedge into a pulley’s grooves much tighter than a flat belt and are thus less likely to cause or transmit vibrations. This is why V-belts are used on a sensitive drill press, requiring very low vibrations.
V-belts tend to be more expensive than flat belts. For this reason, flat belts are typically used in drill presses that aren’t used for sensitive work.
8. Drill Chuck
The drill chuck holds the drilling tool, which is usually a drill bit. This component comprises a sleeve, key, body, and jaws.
The drill chucks usually come with self-centering 3 jaws and may have a chuck key. To get this to work, use the key to loosen the chuck. This will open the jaws, allowing you to insert the metal or wood drill bit. Now, use the key again to tighten the chuck, closing the jaws. Inside the chuck body, a slanted nut revolves around the jaws as you turn the key. This movement causes the jaws to move outwards in a diagonal direction, thus gripping the drill bit.
The chuck key has a slight gear reduction when paired with the chuck body. This gear reduction offers greater leverage and a torque gain. In essence, this means that the chuck jaws exert more pressure on the drill bit than you exert on the key, thus gripping it more tightly than you can accomplish by hand.
Keyless chucks are also available. Here, you would tighten the chuck by hand. Generally, this offers no torque gain, and thus this variety doesn’t grip the drill bit as tightly.
9. Feed Lever (or Hand Wheel)
The feed handle controls the drill bit’s vertical movement, thus determining how fast and how much pressure the drill encounters the workpiece.
Some drill presses don’t have a feed handle and may have an automatic feed or are programmable to lower the drill bit automatically at a set rate or pressure.
The table is connected to the column and is usually moved up or down to suit the work at hand. On some large drilling machines, the table may be fixed and the drill head may be moved up and down. If you have a benchtop drill press, you will unlock the work table lock, move it up or down according to the workpiece height and lock the table in place.
On some machines, this table can be tilted up to 90֯ in any direction, thus accommodating holes drilled at an angle. On most drill presses, the table can be removed to accommodate larger workpieces.
During operation, the table remains stationary, with the workpiece securely clamped to it. The drill bit is moved down into the workpiece, typically using the feed lever. This mode of operation ensures accurate work, along with the safety of the operator and any bystanders.