Using The Drill Press
15th in a series of articles by Barb Siddiqui
As a new or beginning woodworker, it won't take long to realize your work would benefit from the repeatable accuracy of drilling holes with a drill press. Both benchtop and floor models are quite serviceable, and the choice depends more upon how much space is available in your shop, than a preference for one over the other. Large, heavier drill presses usually have a higher horsepower rating, and floor model drill presses can drill holes in the endgrain of long boards more easily.
Drill presses, originally designed for metal work, become efficient woodworking tools with the addition of a plywood or melamine-covered table, and some kind of fence to hold the work against. This arrangement can be as simple as a piece of 3/4" plywood lag-bolted from below the small metal table, and a 2x4 clamped to the plywood (to counteract the torque of the drilling action), or as elaborate as a professionally manufactured table with embedded T-track for hold downs and a sliding fence with micro-adjustments.
Whatever your set up, it is important the workpiece is securely clamped or held down before drilling. Many bits have a tendency to pull the workpiece upward off the table when the operator retracts them from a hole, resulting in the entire board's length being spun in the circular motion of the bit. Clamp each workpiece, or secure it tightly against the fence and downward to the table, by hand.
Before using the drill press, mount a straight piece of steel rod in the chuck and set a small engineer's square on the table in several different positions around it, to assure a drill bit will enter your wood vertically at 90º to the table. Another method to test this is to bend a piece of heavy metal coat hangar into a level 'Z' shape, with one end bent up at 90º, a long straight section, and the other end bent down at 90º. One end is captured by the drill chuck, and the other end set just onto the table. Turning the drill chuck by hand sweeps the bent wire in a broad circle, testing the levelness of your table and its orientation to a drill bit.
One thing you want to avoid when drilling deep holes is heat build up. It is smart to reduce the friction while drilling by occasionally lifting the spinning bit free of the workpiece to allow chip removal, then re-inserting it to cut deeper. Be sure your fingers are well away from the bit. Also, never bury a drill bit below the spiral flutes of its design. They are there to clear away compacted wood chips.
Large holes can be cut with a hole saw in softwoods, or with a fly-cutter, but only on very slow speeds such as 200-400 rpm. If your drill press is not capable of such slow speeds, please avoid using a fly-cutter, as they can be quite dangerous. A router, or even a saber saw, would be preferable.
Setting depth stops can be a problem. Always test the depth of the cut on scrap pieces before committing your good wood. If the measurements and arithmetic cause headaches, there is a shortcut. Before setting the fence distance to align a hole in a workpiece, put a pencil mark on the edge of the wood at the required depth, set the wood beside your drill bit, and lower the bit in open air to meet the pencil line. Lock your depth stop at that point, then set up the fence distance to align for drilling. (But it's still a good idea to test your depth in scrap lumber.)
Brad point bits have distinct spurs on the outer cutting edges of the flutes, and are ideal for drilling wood, but they are not commonly available in the many increments that regular metal drilling bits offer. Spade bits work well, but leave a rougher hole compared to other bits. It is best with any of these, to mark your hole location with a cross-hair marking using a sharp pencil, then indent that point with an awl, so the bit will have a starting point and not wander off -target.
Drill press tables get cut up pretty quickly, and each through-hole you drill needs a backer board to prevent tear-out, so many people cut a replaceable square in the surface of their plywood table. These can be offset rather than centered under the drill chuck, so they can be lifted out and turned to fresh wood on each of four corners, then inverted and used at each of four corners again before being discarded as an expendable item and making another. Any such insert should be of the same thickness, and sit flush with, the table's surface.
Whenever you acquire a new (to you) machine, read and follow the owner's manual. Know how to check it for alignment procedures, lubrication and general maintenance. Be aware of any safety precautions, and then learn by doing.