Laminate Trimmer: Grinding or Squealing Sound

When a bearing wears out, it will produce a grinding, growling, moaning or a low rumbling sound and will usually cause a vibration in the unit. To check and replace bearings, remove the base from the laminate trimmer. Remove the motor cover and release the tension on the brushes by pulling the brush springs to the side and removing the brushes.

Note: some models may have caps on the side, holding the brushes in, which can be removed with a screwdriver to remove the brushes. Make a reference mark on the upper and lower motor housing for reassembly purposes. Separate the upper and lower half of the motor housing by removing the screws, then tap free with a rubber mallet. Remove the collet from the shaft and then use a rag, or glove, to tightly hold on to one end of the armature shaft as you use an impact wrench to remove the chuck. Use a rubber mallet to tap the armature free of the housing.

For units with a bearing mounted inside the housing (instead of on the armature shaft) use retaining ring pliers to remove the retaining ring that holds the bearing in place inside the housing. Next, use a socket that only makes contact with the outer race of the bearing and tap it free from the housing. Next, flip the housing over and insert the new bearing in place. Use a socket that only makes contact with the outer race of the bearing, to avoid any damage to the bearing and tap the bearing in place.

Reinstall the retaining ring. Install the armature back in the housing and tap in place, using a rubber mallet. To replace the bottom bearing, you can leave the armature in the housing. Use a bearing puller to remove the bearing. Apply a small amount of grease to the shaft and then install the bearing on the shaft. Place a socket on the bearing that only makes contact with the inner race, to avoid damage to the bearing. Tap the bearing in place. Reinstall the chuck with the impact wrench as you hold on to the opposite end. Reinstall the collet. Rejoin the two halves of the motor housing, making sure to line up the reference marks. Reinstall the brushes and reapply the tension on the brushes. Reattach the motor cover and then the base.

The carbon brushes supply electricity to the armature by riding on the commutator. Badly worn brushes can cause squealing sounds and excessive sparking. To check the condition of the carbon brushes, remove the motor cap and pull the tension springs to the side. Remove the brushes. Brushes measuring 1/8 of an inch, or less, are worn and require replacement. Install new carbon brushes and reapply the tension springs. Reinstall the motor cap. Some models will have brush caps on the side of the unit for easy access. Unscrew these caps with a screwdriver and remove the brushes. Replace brushes, if needed, and reinstall the caps.

The fan stops the motor from overheating. If the fan is loose on the shaft, it can cause grinding or squealing sounds and will usually be accompanied by a vibration. This repair procedure will vary on all models, but will be similar. To examine the fan, and replace it if it is loose, broken or damaged, remove the base and the motor cap from the laminate trimmer. Remove the carbon brushes.

Some models have caps on the side, holding the brushes in place for easy access, which can be removed with a screwdriver. Make a reference mark on the upper and lower motor housing for reinstallation purposes. Remove the screws securing the two halves of the motor housing together and tap free with a rubber mallet. Remove the collet from the shaft. Using a rag, or a glove, hold on to one end of the armature shaft as you use an impact wrench to remove the chuck. Use a rubber mallet, tap the armature free of the housing. Examine the fan for looseness and breakage. Remove the wave washer. Use a bearing puller to remove the bearing from the armature shaft. Remove the retaining clip and pull the fan off of the shaft.

Install a new fan on the shaft and reinstall the clip to secure it in place on the shaft. Install the bearing with a press or put the shaft in a bench vice with the soft jaws attached to avoid damage to the armature. Use a socket big enough that only makes contact with the inner race of the bearing and tap it in place with a hammer. Reinstall the wave washer and then insert the armature into the housing and use a rubber mallet to tap in place. Reinstall the chuck with the impact hammer. Rejoin the two halves of the motor housing, lining up the reference marks. Reinstall the brushes and reattach the motor cover and the base.