A drill press is a precision tool designed for drilling very accurate holes in various types of hardwoods, softwoods, plywood and other manufactured wood products, metal, plastic and more. The advantage of a drill press over a power drill or a cordless drill is that the solid body construction of the drill press provides a sturdy platform from which to drill. The motor is much larger than a hand-operated drill, and the drilling action is perfectly vertical (when the drill press is tuned properly), allowing the operator to drill precise, even large diameter holes using forstner bits, spade bits or even auger or standard twist bits.
If the drill press isn't properly aligned, the drilling will not be nearly as precise as desired. Tuning up a drill press isn't a monumental task, though; think of most of these steps as standard maintenance that will keep your machine as precise as the day it arrived.
Before getting into some of the mechanical aspects of aligning your drill press, it is advisable to make sure that the base and stand of your drill press are secure. Whether you're using a floor-standing drill press or a table-top model, your unit needs a solid foundation. Be sure that the floor or table onto which the base is situated is flat and level and can easily support the weight of the drill press and any work that may be placed onto the work table.
If possible, mount the base of the drill press to the floor or work table to prevent the possibility of the unit tipping over. Drill presses are very top-heavy, and although they come with a heavy base, an unsecured drill press can be knocked over with enough lateral pressure. Be sure to use a stout lag bolt and anchor with appropriate washers to hold the base securely to the floor or table top.
Verify that the column is mounted securely into the base you just mounted to the floor or table top. Tighten the bolts that attach the column to the base using an open-end wrench or large Allen wrench as necessary. Cautiously but firmly push against the column in every lateral direction to ensure that the base and column are secure. If your unit is mounted on a table top and the table isn't strong enough or sturdy enough to prevent the column from moving, consider installing your drill press on another surface that is more suitable to support the machine properly.
Check the Motor Mount
With the base and column secure, the next step is to verify that the motor head is properly secured to the column. This will vary depending on the type of drill press that you have. Most drill press heads mount directly on top of the column, while a select few raise and lower the drill press head as a master height adjustment.
If your drill press is of the far more common style that the head is mounted on top of the column, tighten the bolts that secure the head to the column. Check to see that the head will not rotate on or rise up off of the column.
Clean and Adjust the Rack and Pinion Gears
Since most drill presses have a head unit that is stationary on top of the column, the drill press table must be raised or lowered to position the work within the range of the quill and chuck. The table is raised and lowered by a locking rack and pinion gear system mounted directly on the column. These gears can become clogged with sawdust and grime over time, preventing the mechanism from operating smoothly to raise and lower the table.
To clean the gears of the rack, lightly spray a cleaning lubricating spray onto the gears, then wipe them down with a lint-free cloth. If the teeth are particularly dirty, clean them with a stiff bristle brush (an old toothbrush works well). Sweep out all of the gunk from the teeth along the entire length of the rack, both above and below the table, then wipe the teeth clean with the cloth.
Loosen the table lock and crank the handle to raise or lower the table along the rack. If the pinion gears in the table mechanism are limited by gunk, you may need to spray cleaner within the mechanism and raise and lower the table a few times to free up the unit. Once the entire unit is functioning properly, spray the rack and pinion with a dry silicone lubricant like Boeshield T-9 to keep the gears functioning smoothly.
Adjust the Table Rotation
Most drill press tables with rack and pinion gear systems also can be rotated out of the way, to any position to the left or right of the column. Check to see that your table can be loosened and rotated around the column. If it is too loose or does not turn freely, adjust the set screw on the collar at the top of the rack gears so that the entire table can turn around the column as needed.
Check the Table for Square
In order to drill holes that are square to the face of the board, the table of your drill press needs to be perpendicular to the motion of the quill. To check the table, position the center of the table directly beneath the drill press chuck and lock the table in place, with the height about eight inches beneath the bottom of the chuck. Insert a large twist drill bit that has no taper (or a perfectly cylindrical machinist's punch) of about 1/2 inch diameter into the chuck and tighten the jaws of the chuck.
Position a combination square on the table and align the vertical side of the square with the side of the drill bit or punch. If you notice any uneven space between the square and the bit (or punch) on either the top or bottom of the alignment, loosen the adjustment lever and tilt the table until it is aligned square to the bit. Tighten the table lock in place, and check the opposite side of the bit with the square to verify that the table is now perfectly square to the quill and chuck. This should ensure that your drilling will be square to the table, as well as any flat wood or other material placed on the table.