Planer: Grinding or Squealing Sound

A bearing is a device that is used to enable rotational, or linear, movement and reduces friction and handles stress at the same. Bearings will wear out over time and with use. When this occurs, the bearing will produce a growling, grinding, or a humming noise and is usually accompanied by a vibration. Repair procedures will vary from model to model.
To access the bearings on the armature, remove the side panel and gearbox cover. Take out the retaining clips on the sprockets and then remove the chain and sprockets. Remove the bolt on the belt tensioning bracket to release the tension and remove the belt. Not all planers have a tensioner, so removing the belt can be tricky. You may have to gently pry it off with a screwdriver as you walk it off the pulleys. Remove any cable hold-downs, followed by the support bolts for the motor housing. Lift the motor up and detach any ground wires under it and then place the motor assembly on a bench. Remove the brush caps and brushes and then the switch from the housing. Take a photo of the wire attachments for easier reassembly.
Now, detach the wires. Remove the switch housing from the motor housing and then feed the wires out of the housing. Take the screws off of the back cover of the motor. Remove the retaining ring behind the pulley on the opposite end and tap the pulley with a rubber mallet to separate the armature from the housing. Pull the cover from the armature with the spring washer and spin the bearings to determine which one is bad. Bearings should spin freely, with no noise. A worn bearing will spin rough and may make a noise.
Pulleys attach in many different ways. Most pulleys will have a nut holding it in place. If yours does not, examine your planer’s pulley for a set screw holding it on the shaft. If your particular model has neither, then the pulley is pressed on and you will have to use a puller to remove it.
Next, use a bearing puller to remove the bearings. If clearances are tight, then use a separator to remove any bearings and tap on the shaft with a mallet, or brass hammer, only to avoid damaging the armature shaft and to free the bearing from the shaft.
Install new bearings into the shaft by using a socket that only makes contact with the bearings inner race to avoid damaging the bearing. Tap the socket with a hammer to seat the bearing in place. Reinstall the pulley. For pressed on pulleys, you can heat the pulley up to expand it for easier installation, then tap it into place. Install the spring washer back onto the armature shaft, with the cover and slide the armature back into the motor housing and tighten the cover. Install the retaining ring back behind the pulley. Feed all the wires into the switch housing and reattach the wires to the switch, referring to the photo you took earlier.
Now, secure the switch back to the housing and reattach the ground wires under the motor housing. Install the motor back onto the planner. Reinstall the power cord hold-downs and install any spacers onto the shafts. Place the sprockets inside the chain and position the sprockets and chain assembly back onto the shafts, aligning the keyways. The hubs on the sprockets face the planer. Install on one feed roller, followed by the second and then slide the assembly all of the way back.
Position the belt on the smaller pulley first, then the larger one. Pull the tensioner back and tighten the bolt to hold the belt tensioner in place. Models without a belt tension can be tricky when installing belts. Carefully maneuver the belt through the clearance, possibly using a screwdriver. Be very careful not to cause damage to the threads on the adjustment rods, or damage the belt itself. When the belt is in position, start feeding it onto the smaller pulley first, then place the end of the screwdriver on the larger pulley nut – only for leverage. Now, gently pry the belt along the larger pulley. Once it is on the pulley a little way, turn the pulley by hand at the same time as you push on the belt to walk it onto the pulleys. Reinstall the gearbox cover and side covers.

A worn-out drive belt will cause a squealing sound because it is stretched and sliding on the pulleys. To check the condition of the belt, remove the side cover. Check the belt for tension. If it is loose, and your model has a belt tensioner, then try and tighten the belt first, before replacing. Examine the belt for uneven wear along the sides, cracks, frays or anything else out of the ordinary.
To replace the belt, loosen the tensioner to remove and reinstall with a new belt and retighten. For models without a belt tensioner, removing the belt can be difficult. Gently pry the belt off of the pulleys with a screwdriver. Avoid using the height adjustment rods for leverage as this can cause damage to the threads on them. Once the belt has been started off of the pulley, you can walk it off by rotating the pulleys and pulling the belt off. You can also just cut it off.
Install the new belt by starting it on the smaller pulley first, then the bigger one. Once again, you might find it easier to use a screwdriver for leverage to get it started on the bigger pulley. Place the tip of the screwdriver on the pulley’s nut for leverage. Never use the adjusting rods for leverage as this will damage the threads. Once the belt has been started a little way on the pulley, continue to walk it on. Finally, reattach the cover.

The carbon brushes ride on the commutator, supplying electricity to the armature. Over time, these brushes will wear out. When they do, they can spark excessively, over heat and cause a grinding sound. To inspect the carbon brushes, remove the brush caps on either side of the motor and pull out the brushes. If the brushes are less than 1/8 of an inch, they require replacement. Look for anything else out of the ordinary, such as chips, cracks, breakage or uneven wear and replace if any of these conditions appear. Install the new brushes into the housing and reinstall the caps to secure the brushes.

The gear case is located behind the chain and sprockets. The gear case is driven by the cutter head shaft and drives the sprocket and chain assemblies for the feed rollers. A grinding noise from the gear case will be obvious when heard. To inspect the gear box, remove the side panel and gear box cover. Detach the clips holding the sprockets and gear assemblies in place and then remove the chain and sprockets. Remove the gear box from the planer, inspecting it for damage. Spin the gears and examine very carefully – you are looking for broken, cracked, chipped and missing teeth. Also check for roughness when spinning. Install a new gear box, if you have determined this is the cause. Reinstall the chain and sprocket assemblies back into the feed roller shafts and secure the retaining ring. Reattach the gear box cover and side cover.

If the planer’s blades are dull, it can cause a grinding or squealing sound. To replace worn out blades, remove the blade hood. Take out all the screws securing the blade. Most planers come with a T-handle tool to remove the screws. The handle has two magnets on either end to pick up two screws at a time – lift them out of the planer. The design also allows you to pick up the blade as well, preventing the risk of injury. While removing the screws, keep pressure on the bar because it is spring loaded. Once all of the screws are removed, lift the bar out using the magnets in the handle then do the same with the knife. Now, remove the springs.
Clean out the inside of any dirt and debris so that the new knife and bar will lay flat. Then, reinstall the springs. Some blades are double-sided, so you can just flip them around to the harp side, or install new ones. Reinstall the bar and make sure it is positioned on the nipples to hold it in place. Insert the screws on each end first – to keep the springs down – then install the rest of the screws. Tighten the screws hand tight at first, then go around a second time and tighten with the T-handle tool. You will have to do this for each blade on the cutter head. Once complete reinstall the hood.

Pulleys are attached to shafts and are used to transfer power between shafts via belts. If you start noticing a grinding or squealing sound, it could be a worn out pulley. Examine the pulley by removing the side cover off of the planer and then take out the belt. Some models will have a tensioner you can loosen and slide to remove the belt. For models without a tensioner, it can be quite difficult and tricky to remove the belt. You may have to slightly pry it off with a screwdriver, to get it started, and then walk it off. Never use the adjustment height rods as leverage as it will damage the threads.
With the belt off, wiggle the pulley for play and replace, if you notice any. Spin the pulley and listen for any abnormal noises. Remove the nut securing the pulley, followed by the pulley and keyway. Install the new pulley, with the keyway lined up, and tighten the nut. Reinstall the belt. Clearances are tight between the pulleys with the adjusting rods and the housing of the planer. It can be very tricky maneuvering the belt through these clearances to the pulleys.
Once you have successfully maneuvered the belt in place, install the belt on the smaller pulley first, then the larger pulley. You may need a screwdriver to slightly pry it over. Place the screwdriver on the pulley nut, only for leverage to avoid any damage. Once the belt is all the way around the pulley, you can walk the belt on by turning the pulleys and pushing on the belt. Reinstall the side covers.

Bushings are metal linings for a round hole, which an axle revolves. They are very similar to bearings; over time, they will wear out and cause a grinding or squealing sound. The bushings are located on either side of the feed roller shafts. The following repair procedure will vary on all models, but will be similar.
To replace worn bushings, remove the side covers and the gearbox cover. Remove the retaining rings from the sprockets and pull off the sprockets and chain assembly as a unit. Do not loosen any keyways, if they are separate. Remove any spacers on the rollers and then raise the cutter head to the top and lay the planer over on its side. Remove the retaining brackets that secures the rollers to the planer – be careful not to cut yourself on the cutter head as you work around it. Located behind the rollers bushings are springs that keeps the pressure on the feed rollers. Remove the rollers slowly to avoid the springs from popping out and getting lost. Remove the bushings and inspect them for wear, such as scoring or any other signs of damage which will appear on the rollers surface. With the bushings on the roller, you can check them for any signs of play.
Replace any bushings showing signs of wear or damage. If the rollers shaft is damaged bad enough, then replace the rollers as well. The planer’s bushings are wider in one direction than the other. The wider part of the bushing should be up and down, to allow the bushing to fit tightly inside the planer.
Reinstall the brackets that secures the feed rollers in place. One of the brackets may have elongated holes – this bracket attaches to the opposite end of the chain and sprockets. Keep pressure on the roller pushed against the end when you’re tightening down the first bracket. Make sure the second bracket is tight against the bushing and that there is zero play. Install the spacer back on the roller and then insert the sprockets inside the chain. The hubs on the sprockets face inward. Install on one feed roller, followed by the second inside the chain. The hubs on the sprockets face inward. Install on one feed roller, then the second, making sure to align the keyways. Now, slide it back all of the way. Reinstall the retaining rings on the sprockets, the gearbox cover and the side covers.