How do you tame a bucking drill press?
While helping a friend with a project in his shop, I was amazed by the quiet, smooth running of his drill press. It made me realize that the vibrations in my machine may be causing the less-than-perfect results I typically get. How can I improve my drill press performance? It's a standard belt-drive floor model.
—Fred Stein, Atchison, Kansas
You're on the right track, Fred. Reducing vibration will make your drill press last longer and give you more precisely rounded holes. Misaligned pulleys or worn-out belts are the prime suspects, so here's how to deal with both problems.
Unplug the drill press, and pop open the lid that conceals the pulleys. Here, you may find black dust: rubber particles that used to be part of the drive belts. To check for excess wear in the thickness and width of each belt, remove the belts and slowly run them between your thumb and forefinger. If you notice any irregularities, buy replacement belts at your local auto-parts store or from a tool supplier. We don't recommend using a belt dressing. This might also be a good time to replace your standard V-belts with link belts made from interlocking segments. These won't form humps when left curved around pulleys for long periods.
With the belts still removed, plug in the drill, and switch it on to check that the motor runs smoothly and the drive pulley doesn't wobble. Replace the motor if the bearings have worn to the point where the shaft wobbles. Replace the pulley if it has been worn or damaged by a misaligned belt.
The next step is aligning the pulleys so the belts run in a straight horizontal line. In many drill presses, you can adjust the height of only the drive pulley. To do this, raise the motor by loosening the bolts through its base or merely adjust the vertical position of the pulley on the motor shaft, as shown in the photo above.
A straightedge helps you align the height of the drive pulley on the motor with the center pulley, called the idler pulley because it transfers energy from the motor to the drill shaft.