Planer: Won't Adjust up and Down or Binds

A broken chain will not be able to turn the sprockets, raising and lowering the cutter head on the lead screws. To inspect the chain, remove the top cover. If it is broken, or has a lot of slack, you will have to install a new one. Remove the entire handle assembly and the cover underneath it. Remove the top side cover from the opposite side. Pull the chain off and then release the tension on the tensioner. Position the new chain around the sprockets.
Now, reapply the tensioner. Reassemble the top cover, the two side top covers and the handle assembly back onto the shaft. A broken chain will not be able to turn the sprockets, raising and lowering the cutter head on the lead screws. To inspect the chain, remove the top cover. If it is broken, or has a lot of slack, you will have to install a new one. Remove the entire handle assembly and the cover underneath it. Remove the top side cover from the opposite side. Pull the chain off and then release the tension on the tensioner. Position the new chain around the sprockets. Now, reapply the tensioner. Reassemble the top cover, the two side top covers and the handle assembly back onto the shaft.

A broken, dirty, dried up or gummed up gear can cause the planer’s adjustments to bind or not adjust at all. Turn the planer on its side and examine all the gears underneath. If there are no gears underneath, then your planer uses a chain and sprocket system instead. Look under “chain” or “sprockets” for repair procedures. If you notice anything else, such as a broken or damaged gears, or if it is in desperate need of a cleaning and re-lubricating, you will have to disassemble in order to fix it.
Remove the top of the planer, followed by the side covers and gear box cover. Take out the retaining clips, holding the sprockets and chain on. Remove the bolt on the belt tensioning bracket to release the tension and remove the belt. For models without a belt tensioner, removing the belt can be tricky. You may have to gently pry it off with a screwdriver as you walk it off the pulleys. Make sure you only place the tip of the screwdriver on the pulleys nut for leverage to avoid damaging other parts. Remove the bolts securing the motor housing to the planer and then the power cable hold-downs. Lift up the motor and detach any ground wires under it. Turn the handle, raising the cutter head to the top, until the handle comes off. Continue to turn the lead screw by hand to the top.
Now, remove the pillar nuts. Mark your pillars before removing them so when you reassemble, you are placing them back into their original spots. Pull out the pillars, followed by the cutter head from the lead screws. Remove the screws holding down the bases of the lead screws and then pull out the lead screws. Mark the lead screws so they can go back into their exact same housing. Take out the nut on the end of the lead screws and pull off the gear. Remove everything else off of the shaft and clean in a parts cleaner, then lubricate them. Reassemble everything back onto the shaft in proper order.
Install the new gear, if you are replacing a broken one. Reinstall the nut to hold everything into position on the shaft. Turn the base over and the two gears on the shaft will come right off. Clean and lubricate these two gears or replace any broken gears by just sliding new ones onto this shaft. Turn the base back over and install the lead screws back into the housing and secure – the longer one is for the handle. Make sure you put the lead screws into their original housing. Tilt the base back over and start assembling the pillars back in their correct marked housing. Hand-tighten the nut, only at the bottom of the pillars.
Install the cutter head back onto the pillars and lead screws, carefully aligning everything up. Turn the lead screws counter clockwise to get the cutter head to come down. Install the handle temporarily, then you can bring the cutter head all of the way to the bottom. Loosen each pillar – one at a time – and then tighten it back up. Once they are tight, give them a quick snug. Remove the handle and reinstall the top shield – now you can reinstall the handle permanently. Place two objects of the exact same dimension all the way through the planer. Make sure the cutter head is flat, on the bottom (no blades). Place the two objects of equal dimensions as far apart from each other, under the cutting head. Slowly bring the cutter head assembly down as you rock the cutter head back and forth, to where it stops moving when it makes contact with one of the objects. When this happens, you will have to make adjustments so the opposite side makes contact at the same time. This will level off the cutter head for straight cuts. Loosen the adjustment nut on the lead screw you need to adjust the height on. Turn the adjustment screw by hand, or a wrench, until the excess gap is gone. Once the gap is gone and the head is level, tighten the adjusting nut to secure it in place.
Double check to make sure the adjustment is correct by following the above steps. You may need to do this a few times to get it perfect. Reinstall the motor, but first make sure to reattach the ground wires under the motor. Reinstall the power cord hold-downs. Install the spacer back onto the roller shaft and then place the sprockets inside the chain. Position the sprockets onto the shafts, aligning the keyways. The hubs on the sprockets face the planer. Install onto one feed roller, and then the second, for easier installation. Once positioned on the shaft, you can now slide all of them back. Reinstall the belt on the pulleys, adjust the tension and tighten the bolt.
For models without a belt tension, this can be a tricky procedure and will require patience. Carefully manoeuvre the belt through the tight clearances between the housing and the threaded rods, possibly using a screwdriver. Be careful not to damage the threads on the adjustment rod or the belt. 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 then, gently pry the belt along the larger pulley. Once the belt is on the pulleys a little way, turn the pulley by hand at the same time as you push the belt to walk it onto the pulleys. Reinstall the gear box cover and side covers.

A crank handle is attached to a the shaft by either a nut or a set screw. To replace a broken handle, remove the nut or set screw and pull the handle off. Install the new crank handle and fasten it in place. 

If a knob is broken, you will not be able to make any adjustments. Knobs are held on to shafts by either a nut and washer or a set screw. To replace a broken handle, remove the nut/washer or set screw. Install the new handle and reinstall the set screw or washer and nut. Some handles might be held in place by a pin that you can tap out. Once the handle is in position, tap the pin back in place.

Some planers have a sprocket and chain assembly that is used for lowering and raising the cutter head. This assembly is located at the top of the planer, inside the cover – opposed to gears and shafts, underneath the base of the planer. To inspect the sprockets for any broken, or damaged, teeth, you will have to gain access to them. Remove the entire handle assembly on one side and the top cover underneath it. Then, remove the side top cover from the opposite side of the planer. Remove the main top planer and release the chain tensioner. Now, remove the chain from around the sprockets, followed by the screw securing the sprockets in place and take out the washer and sprocket. Install the new sprocket, with the washer, and secure it with the screws. Reinstall the chain onto the sprocket and reapply the tension. Reinstall the side covers, top cover and the entire handle assembly.