Hammer Drill: Bad Vibration
When a hammer drill has bad vibration it can make the accuracy of your work difficult. In many cases, the parts that cause this issue are the carbon brush, handle, housing, bearings, gears, and spindle. Once you have located the part that is causing the problem, read on for expert repair advice and instructions on fixing your tool yourself. Refer to your owner's manual for tips specific to your model.
The following repair procedure will vary as all models are different. To replace a bearing that has worn out, remove the handle then proceed to open the drill case by removing the screws holding it together. With the case open, remove the spindle/chuck assembly and the lift the field up and remove the armature out of the field. You may have to remove the carbon brushes before taking out the armature. Now, you can check all of the bearings by spinning them by hand and listening for an abnormal sound. If the bearing does not spin, then it is seized.
To replace...
The following repair procedure will vary as all models are different. To replace a bearing that has worn out, remove the handle then proceed to open the drill case by removing the screws holding it together. With the case open, remove the spindle/chuck assembly and the lift the field up and remove the armature out of the field. You may have to remove the carbon brushes before taking out the armature. Now, you can check all of the bearings by spinning them by hand and listening for an abnormal sound. If the bearing does not spin, then it is seized.
To replace a bearing on the armature, use a bearing separator. Once you install your separator on the bearing, place the separator on top of a bench vice open far enough that it will not make contact with anything but the separator. Tap on the shaft with a punch and a hammer, until the bearing is free. For this step, you also can use a bearing puller to remove the bearing. To install a new bearing, place a socket on the inner race of the bearing, to avoid damage to the bearing, and tap it in place with a hammer. Reinstall the armature into the field and then the carbon brushes and spindle/chuck assembly back in the drill housing. Secure the case back together and reattach the handle.
The following repair procedure will vary between models. To replace a bearing on the spindle assembly, remove the cam plate, leaf spring, change plate, steel ball, gear, and the retaining ring. Use a bearing separator, or a puller, to remove the bearing from the spindle. Install the new bearing on the spindle by using a socket that only makes contact with the inner race of the bearing to avoid damage to the bearing. Tap in place with a hammer. Reinstall the retaining ring, gear, steel ball, change plate, leaf spring, and cam plate. Reinstall the spindle assembly into the drill case and reassemble the case back together. Reattach the handle back on the hammer drill.
Some models may have a secondary shaft, with gears, that you can remove at the same time with the spindle/chuck assembly. To replace gears on this shaft, remove it from the drill case and remove the bearings with a separator or puller. Remove any retaining rings and then the gear or gears with the keyway. Install the new gears on the shaft with the keyway, ensuring the keyway stays in place. Reinstall any retaining rings and the bearings. When installing the bearings, use a socket that makes contact with the bearing inner race to avoid damage. Tap in place with a hammer then reinstall the secondary shaft into the drill case.
If the worm gear on the end of the armature is worn, or broken, it is usually part of the armature itself, therefore requires the replacement of the armature. Lift the field up and remove the armature out of the field, using a bearing puller or separator to pull out the bearings (if the new armature assembly does not come with bearings). Install the bearings in the armature by using a socked, placed on the inner race of the bearing and tap it in place with a hammer. Reinstall the armature in the field and reassemble the case. Reattach the handle.
Continue to remove the chuck. Remove the front gear cover and/or separate the two halves of the drill case, depending on your model. Remove the spindle and separate the cam plate, leaf spring, change plate, steel ball, gear with keyway and retaining ring. Remove the bearing from the spindle with a bearing separator...
Continue to remove the chuck. Remove the front gear cover and/or separate the two halves of the drill case, depending on your model. Remove the spindle and separate the cam plate, leaf spring, change plate, steel ball, gear with keyway and retaining ring. Remove the bearing from the spindle with a bearing separator or puller. Take out the compression spring and install on the new spindle. Install the bearing on the new spindle by placing a socket on the inner race of the bearing to avoid any damage to the new bearing. Tap in place with a hammer.
Reinstall the retaining ring, gear, steel ball, change plate, leaf spring and cam plate. Reinstall the spindle assembly on the drill case and fasten the case back together and/or reattach the front gear cover. Secure all fasteners and thread the drill chuck back on the spindle. Open the chuck and insert the allen wrench. Clamp the chuck down on the allen wrench then turn it to hand tighten the chuck. Reinstall the chuck screw and tighten it, remembering it is reverse thread. Reattach the handle.