Bearing Modification for Lortone tumbler models 33b, 45c, and the discontinued 3-1.5b
by Nick Muto
The issue being the plastic “bearings” that these models come with. As the tumbler is
continually operated and the bearings are repeatedly oiled, they become gunked up and the bearings must be replaced or cleaned or the barrel will slow down or may not even turn at all. Even worse this puts more tension on the motor and can cause excessive heat and can even prematurely ruin the motor.
This modification eliminates the cheap plastic bearing and replaces it with a flanged steel bearing. The benefit is the longevity of the the bearing, constant smooth operation and minimal oil usage.
This is an excellent modification, and fairly easy for anyone to do, but I am not responsible or liable if something doesn’t work correctly or, for example you overdrill a hole and ruin the tumbler. This is a permanent modification, and the original bearings will no longer work upon completion. Take your time, pay attention and use proper safety equipment when using tools. If you get confused in disassembly, take pictures of parts and screws to show you how everything went together.
Parts Needed: Four 8x16x5mm Flanged Shielded Chrome Steel Bearings, Four #8 32×1/2″ machine screws and Four #8 32 machine nuts.
Tools Needed: Drill, a 4in1 screwdriver or other phillips and flat head screwdriver, 11/32 and 1/8 drill bits, small crescent wrench, needle nose pliers, #2 metric Allen Wrench, step bit capable of making a 5/8 hole, and 3in1 oil for bearing lubrication.
Disassembly and modification:
- Unplug the tumbler and prep an area to work.
- Remove top and bottom motor covers with phillips screwdriver and set aside.
- Remove belt by working it off the pulley, inspect and set aside.
- Using the Allen Wrench, loosen and remove large pulley from tumbler and set aside.
- Remove C clips at the four ends of rollers using a screw driver or needle nose pliers.
- Remove roller shafts and old plastic bearings.
- Set aside the clips and rollers and put away or discard the original plastic bearings.
- Using a drill and 1/8 drill bit, drill out just the heads of rivets on the top side of the tumbler and use needle nose pliers on underside of rivets to remove.
- After drilling out the two rivets on top side, switch to the 11/32 bit and drill through housing and motor mount holes for screws that will be used during reassembly.
- Repeat this step on bottom side of tumbler.
- After all 4 rivets are removed and new holes are drilled, pull the motor mounted piece away from main body of tumbler and set aside.
- Keep the motor mount piece assembled as there is no reason to remove the motor or fan pulley.
- Using the drill and Step bit slowly enlarge the four bearing holes until you have reached the 5/8 mark or if you are unsure, slowly drill and continue to check and see if the bearing will pop in.
- When the proper 5/8 hole has been achieved, the bearing will just fit in and the flange will keep it from going any further.
- After making sure bearings will properly fit, take a minute to wipe down and clean up tumbler housing and check for any metal burs from drilling.
- Take the four bearings and apply a couple of drops of oil in between the outer and inner parts of the bearing.
- Move the bearings around with your fingers to get oil distributed. wipe excess oil from bearings with a rag.
Reassembly of tumbler:
- Reinstall roller shafts using new bearings and C clips.
- The large body of the bearings will be on the inside of the tumbler body where the barrel normally sits and the flange side of the bearing will be on the outside of the housing where the C clip goes.
- The roller shafts and bearings install the same as it was before disassembly, you are just using the new bearings now instead.
- Reinstall large pulley onto roller shaft and temporarily tighten.
- Place motor mount back into tumbler assembly and install the new screws and nuts into the newly drilled holes and tighten snug.
- Reinstall the belt onto the bearings, loosen the large pulley and adjust it with fan pulley to make a straight line.
- When happy with alignment, tighten large pulley snug with Allen Wrench.
- Re-check your work making sure all screws are tightened down and all parts are installed correctly.
- With the top and bottom covers still off, plug in the tumbler and let it run for a minute to make sure everything is working as it should.
- Unplug tumbler.
- Reinstall top and bottom motor covers and tighten into place.
- Load your tumbler as you normally would and tumble away!