How to Correctly Set-up a Drill Press - Part II

using a drill press
DRILL PRESS ADJUSTMENTS

Most drill presses are thoroughly tested, inspected and accurately aligned before leaving the factory. However, moving parts will wear, and the abrasive action of dust and dirt adds to this wear. Rough handling during transportation also can throw the machine out of alignment. Eventually, adjustment and realignment are necessary in any machine to maintain accuracy -- regardless of the care with which the tool is manufactured.

Quill Adjustments. The quill travels in a bored hole in the head casting. These parts will remain accurate indefinitely if kept clean and lubricated according to instructions.

The spindle is raised or lowered by the hand lever. The quill can be locked at any desired point in its travel by tightening the quill locking screw. This is an especially desirable feature for operations such as sanding. Any play that might develop between the head and quill after considerable use can be taken up by partially tightening the quill locking screw.

For operations such as sanding, where the quill is clamped in place, always keep the quill as high as the work will permit so that any side thrust will be transmitted directly to the head casting.

Belt Tension. The belt should be just tight enough to prevent slipping. Excessive tension will reduce the life of the belt, pulleys and bearings. Correct tension is obtained when the belt can be flexed about 1 in. out of line midway between the pulleys, using finger pressure. To adjust belt tension, follow the manufacturer's instructions found in the owner's manual. Generally, this is accomplished by moving the motor bracket to the required position.

If the drill press is equipped with a 1,725 rpm motor, the typical spindle speeds are approximately 250 to 3,000 rpm. The highest speed of 3,000 rpm is obtained when one belt is positioned on the smallest pulley of the spindle and the largest pulley of the center pulley, while the other belt is placed on the smallest pulley of the center and the largest motor pulley.

Similarly, to obtain the slowest speed of 250 rpm, place the first belt over the largest spindle pulley and connect it to the smallest center pulley; run the second belt over the largest center pulley and the smallest motor pulley. When you change the belt position to change speed, always disconnect the machine from its power source.

Benchtop drill press
Inserting Drills. The standard geared or keyed chuck is opened and closed with the chuck key provided. It also can be worked by hand, although the final grip tension must be applied with a wrench. Be sure the drill's shank is centered between the chuck's jaws and is properly secured in the chuck before the power is turned on. Do not apply further pressure with pliers or wrenches after you have hand-tightened the chuck with the chuck key.

Always remove the key immediately after you use it. Otherwise, the key will fly loose when the drill motor is started and may cause serious injury. Self-ejecting chuck keys are available.

Centering the Table. In average drilling operations, the hole in the center of the table should be directly under the drill so that the drill, after going through the work, will enter the hole in the table. When through drilling is being done, the quill always should be brought down first without the work in place to make sure that the drill enters the table opening.

Check to see if the head is set perpendicular to the table by placing a drill bit in the chuck. Then place a combination square on the table, if not square, readjust the table until the drill bit is perpendicular to the table.

Adjusting the Spindle Return Spring. For the purpose of automatically returning the spindle upward after a hole has been drilled, a coil spring enclosed in a metal case is fitted to the side of most drill presses. (Check your owner's manual for the exact details.) Generally, this spring is adjusted at the factory and usually requires no further adjustment. If, however, the spindle fails to return to a normal position, or if the return is too rapid, the tension should be adjusted. This is done by loosening the lock-nuts that hold the case in place. They should not be completely removed, but simply backed off about 1/4 in., enough so that the case can be pulled out to clear the bosses on the head. As the case is pulled out, it must be held tightly to prevent the spring from unwinding. The case is turned clockwise to loosen the spring; counterclockwise to tighten it. When the quill is up, two full turns from a non-tension position should give the proper tension. Before tensioning the spring, it is well to slack it off entirely. It should be noted that the exact method of adjusting the spindle return spring varies with different models and makes of drill presses. Consult the owner's manual supplied with your machine for specific details.




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