One of my double-barrel rock tumblers is dying a slow and noisy death. I thought the noise was coming from the rollers, so I oiled up the bearings but it was still noisy. Yesterday, I shut it down and did a better examination and it seems the noise is coming from a bearing on the motor shaft. Not a problem, I just oiled that too and the noise quieted down.
This morning, the noise is back. Shut it down again, and the sound may be coming from the electric motor. I got out the canned air and blasted the carbon dust out of the armature housing. Then, I oiled all the bearings again, but this time I flooded them to flush out dust or debris.
By this afternoon the noise was driving me bonkers. I logged on to The Tumbler's Bench and ordered a new motor. They had pairs of sealed motor bearings on sale so I grabbed two pair. This evening I received an email that the parts have already shipped! Now that is quality service.
By this weekend, I will be doing a complete rebuild of this rock tumbler. If I kept the box and the receipt I could have returned it. My experience with rock tumblers has been that you get another faulty one in exchange. But if you buy the parts from a third party and rebuild the machine yourself, it seems to last much longer.
I rebuilt the National Geographic (made in China) single-barrel machine in the same way. I replaced the ball bearings with sealed motor bearings and replaced the motor with a slow-speed, high-torque motor. It has been running smoothly 24/7 for almost a year.
If you want something done right, sometimes you just have to do it yourself.