How to Tune Up a Drill Press

Tuner works on drill press

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A drill press requires some occasional maintenance to ensure that it continues to run smoothly and drill precisely. If you don't take care of your machine, it can eventually develop damaging rust on the table, run-out and wobble with the quill and spindle (which drives the chuck of the drill press), and more. By checking a few key areas periodically, you can keep your unit running smoothly and drilling precisely.

Tools and Supplies You Will Need

  • Wrenches
  • Replacement electrical cord or switch (if needed)
  • Replacement drive belt and pulley (if needed)
  • Allen wrenches
  • Rust-resistant metal protectant
  • Rags

How to Tune the Drive System

Most drill presses use a belt and pulley system for transferring power between the motor and the quill. The entire system is housed in a compartment within the head of the drill press.

  1. Check the power cord: Before removing the head cover, unplug the power cord from the electrical outlet, and check the condition of the power cord. Make sure that there are no cracks in the insulation of the cord, and check to see that it is solidly connected to both the plug on the end of the cord and into the motor housing on the back of the drill press. If any damage is present, consider having the cord replaced.
  2. Check the switch: While you're at it, check the condition of the switch on the front of the drill press. There should be no excessive play within the switch, and it should consistently and easily turn the motor on and off. As with the cord, if it is damaged, the switch should be replaced.
  3. Check the belt: With the electrical cord unplugged, open the head cover on top of the drill press. Begin by visually inspecting the condition of the belt between the two pulleys. If the belt is worn or is displaying cracking or fraying, replace it with a new belt.
  4. Inspect the pulleys: Next, rotate the belt slightly on the pulleys and inspect each of the pulleys fore and aft for any damage or cracks. As with the belt, if a pulley is damaged, it is better to replace it than to continue to use a damaged part.
    There are two predominant styles of drill presses: those with multiple pulleys fore and aft (for controlling the speed of the chuck), and those with a single pulley on the motor and quill shaft that employ a variable speed control. In the case of the former, to adjust the speed at which you drill, you'll place the belt on different corresponding sets of pulleys. When you use a larger motor pulley with a smaller quill pulley, the drill chuck spins faster. Conversely, using a smaller motor pulley and a larger drive pulley results in a slower RPM rate for the chuck. Most units of this type will have a chart within the head cover that shows the RPM rate for each corresponding set of pulleys.
    If your unit is a multi-pulley system, you should find a small set-screw on both the drive pulley and the quill pulley. Tighten each set screw with an Allen wrench to ensure that the pulleys are securely fastened.

How to Tune the Quill Assembly

Once you know that the pulleys and belt are in good working order, move on to the quill.

  1. Remove the chuck and set it aside for the moment.
  2. Grab onto the exposed lower end of the quill and move it laterally in any direction, checking for play between the quill and the quill tube of the drill press housing. A loose quill will cause some wobble of the chuck when the drill press is operating, which can cause imprecision. This is especially problematic when using very clean drill bits such as a forstner bit or a sharp-pointed bit such as a spade or auger bit.
  3. If you find that your quill has some wobble, you should be able to tighten the mounting bolt that secures the quill tube into the motor housing with a wrench to reduce or even eliminate the wobble. Then check the quill again for looseness before reinstalling the chuck.

How to Clean the Table

Most drill presses come with a solid table, often made from cast iron. While such a table provides a very solid platform on which to work, it is also very susceptible to rust. You can clean the table much like you would a cast iron saw table, then protect it using a rust-resistant protectant, such as Boeshield T-9. If you allow the rust to remain on the table, it can affect the ability to finish many fine hardwoods and even sanded plywood. By keeping it clean, not only will your table last longer, but your projects will avoid damage from a rusted table.