Rock tumbler motor replacements and repairs: what we've learned so far.

December 26, 2023

We will continue to add to this blog post, but here's what we've tried for repairing the tumblers we have.

(We receive a small commission if you purchase through some the links below at no cost to you.)

National Geographic professional tumbler

National Geographic Rock Tumbler

National Geographic belts are easy to replace.

A good source for belts is Amazon. Specifically, these:

National Geographic Rock Tumbler Replacement Belts

National Geographic tumbler motors are easy to replace.

Just flip the tumbler over and peel off the little round sticky screw covers. Keep a rag handy to wipe away gray dust. Use a phillips head screwdriver to remove the screws. Pull off the bottom to peek inside.

How to replace Nat Geo: https://youtu.be/QIrNpuBIqUQ?si=b1BT94Dg2gLmNKzw

Source of new Nat Geo motor info: https://reddit.com/r/RockTumbling/s/GdScsynV9F

These are so easy to replace, but you still feel like you're a rock star. Why have we replaced so many? Because we have many. I love these tumblers and their warranty. When a tumbler burns out under warranty, they either send a motor or a replacement tumbler. Then I'm not going to trash the old frame if they send a full replacement.

Motor purchase (we have bought three so far and they are great, just slightly slower than original motors): https://www.ebay.com/itm/275090138548

Lortone QT12/66

Lortone belts are easy to replace:

The tumbler stopped turning with both barrels, then stopped with one barrel. When I had no barrels on it, the rollers would spin, so the motor was working, but when I put a finger on the roller, it would stop moving while the engine purred on. So I removed the cover with a 9 mm ratchet wrench and felt the belt. It was loose. Lortone QT12 motor loose belt

Then I used an 8 mm ratchet wrench to adjust the two bolts to the right to tighten the belt. By shifting them right and tightening, the belt had enough tension to continue operating.

8mm ratchet wrench to fix lortone QT motor issue

This kept the barrels turning for a couple of months before the belt got too loose again. So I ordered a new belt from KingsleyNorth.com (it was sold out from my preferred vendor, rockshed.com).

With the new belt in hand, I loosened the screws again and brought the motor to the left to create slack to remove the old belt and put the new one on. Then it's just a matter of moving the motor right again and tightening the screws to make sure there is enough tension on the belt. Both barrels are rolling happily now.