How to Replace the Lower Spindle Bearing on a Jet Drill Press
Power tools use many bearings to allow various components to rotate. Over time, a ball bearing will wear and begin to fail. A spindle bearing that is failing will usually give warning, often with a squeaking or squealing sound.
Let's get started.
REMOVING THE BEARING
1. Disengage the scale seat.
a. Remove the two screws securing the seat to the body of the drill press.
b. Pivot the seat away from the coil spring assembly.
2. Remove the coil spring assembly.
a. Remove the outer nut securing the coil spring assembly.
b. Press and hold the coil spring assembly against the body of the drill press.
c. Loosen (but do not remove) the inner nut securing the coil spring (approximately 3/8" from the spring plate).
d. Use a large screwdriver to pry the coil spring assembly away from the body of the drill press. Caution: The spring will uncoil rapidly, so be sure to keep your fingers away from the assembly during this step.
e. Once the spring tension has been released, remove the inner nut from the shaft.
f. Remove the coil spring assembly from the shaft.
3. Remove the quill assembly.
a. While holding the quill assembly with one hand, carefully slide the feed shaft assembly out of the drill housing.
b. Lower and remove the quill assembly from the drill press.
4. Remove the chuck.
a. Insert a drift punch into the slot on the side of the quill.
b. Tap the drift punch with a hammer to free the chuck (and arbor) from the spindle.
c. Remove the chuck and arbor assembly.
5. Remove the spindle.
a. Insert a drift punch into the slot on side of the quill (to prevent the spindle from rotating).
b. Place the blade of a screwdriver into one of the notches on the spindle nut.
c. Angle the screwdriver so that the bottom of the blade presses against the side of the notch on the nut.
d. Use a hammer to tap the end of the screwdriver until the spindle nut begins to rotate.
e. Continue tapping the screwdriver with the hammer until the spindle nut is loose enough to rotate with the screwdriver alone.
f. Unthread and remove the spindle nut from the spindle.
g. Use long-nosed pliers to remove the (toothed) lock nut from the spindle.
h. Use long-nosed pliers to remove the flat washer from the spindle.
i. Remove the drift punch from the quill.
j. Use a rubber mallet to tap the end spindle (until the spindle breaks free from the bearing).
k. Remove the spindle from the quill.
6. Remove the lower bearing.
a. Use a blind bearing puller (and slide hammer) to remove the lower bearing from the quill assembly.
b. If the upper spindle bearing (the smaller one) also falls out; simply set the bearing aside for re-installation in later steps.
INSTALLING THE NEW BEARING
7. Install the large bearing.
a. Position the new bearing on the quill assembly.
b. Use a hammer and punch to carefully and evenly tap (and seat) the bearing into the quill. (Align the punch with the outer race of the bearing only; do not tap against the inner bearing race or the bearing shield.)
REASSEMBLING THE UNIT
8. Reinstall the spindle.
a. Install the spindle into the quill assembly (through the new bearing).
b. Tap the end of the spindle with a rubber mallet to seat the spindle in the new bearing.
c. Reinstall the upper bearing (over the spindle; into the upper portion of the quill).
d. Use a hammer and punch to carefully and evenly tap (and seat) the upper bearing into the quill.
e. Install the flat washer.
f. Install the (toothed) lock washer. (The inner notch on this washer must align with the slot on the spindle.)
g. Insert the drift punch into the slot on the quill (to prevent the spindle from rotating).
h. Install and hand-tighten the spindle nut.
i. Use a screwdriver and rubber mallet to tap-tighten the spindle nut against the lock washer.
j. Once tight; tap the spindle nut (as necessary) to align one of the notches on the spindle nut with one of the teeth on the lock washer.
k. Use a small screwdriver to bend the tooth on the lock washer up and into the notch on the spindle nut. This will prevent the spindle nut from loosening.
9. Reinstall the chuck.
a. Remove the drift punch from the quill.
b. Thoroughly wipe away any grease or debris from both the tapered arbor shaft and the inner spindle shaft.
c. Install the arbor shaft (and chuck) into the spindle shaft.
d. Open the drill chuck.
e. Use a rubber mallet to tap the end of the drill chuck and seat the arbor shaft into the spindle.
10. Reinstall the quill.
a. Install the quill assembly into the drill press.
b. Rotate the spindle pulley (on the top of the drill press) until the spindle shaft engages with the pulley assembly.
c. Slide the quill assembly (up) into the drill press until the gearing (on the quill) is visible through the opening for the feed shaft.
d. Carefully install the feed shaft, rotating the assembly (as necessary) to align and engage the gearing.
11. Reinstall the coil spring.
a. Install the coil spring assembly onto the exposed portion of the feed shaft, aligning the center (straight) leg of the spring with the slot on the shaft.
b. Install and tighten the inner nut until there is approximately 3/8" between the nut and the spring plate.
12. Tension the coil spring.
a. Protective gloves are recommended for this step.
b. Grasp and rotate the coil spring assembly counter clockwise to add tension to the coil spring.
c. To reposition your hands, press the coil spring assembly against the body of the drill until the inner spring engages the indexing notch on the housing.
d. Continue tensioning the coil spring until the quill assembly retracts into the drill housing.
e. To test the tension of the spring: tighten the inner nut; extend the quill (using the handle bars); then release the handle bars. The quill should retract (spring) firmly and consistently back into the upper housing. If not; loosen the inner nut and increase tension on the coil spring. Repeat this step until the coil spring is ideally tensioned for your specific application.
f. Once the coil spring is ideally tensioned, tighten the inner nut and re-test the quill. The goal here is to tighten the inner nut sufficiently to prevent the coil spring from pulling away from the housing (and uncoiling); but loose enough to allow the quill assembly to glide (extend and retract) freely. Repeat this step until the inner nut is ideally tensioned for your specific application.
g. Use adjustable pliers to hold the inner nut (to prevent it from rotating further).
h. Install and tighten the outer nut to secure the coil spring.
13. Engage the scale seat.
a. Pivot the scale seat back into position against the body of the drill press and align the mounting holes.
b. Secure the scale seat with the screws.