KomeStone K1 Pro Brushless Rock Tumbler Kit for Adults, Quiet 2.5 Lb

I first have to say I purchased this unit on sale it appeared good quality and robust. I had never really used a rock tumbler since I was very young. Then it was a novelty item given to me by my parents. Living on the beach with a variety of rocks all over the place I went to work collecting and had this unit working for a couple months at a time never stopping except to change grits. To my dismay the motor stopped. I contacted the seller. Gave them the situation, within a week I had a replacement motor. They were fast to respond for the initial contact (24 hours). After sending a video I was back up and running in a week. I sure can't complain. Thank you. As to the quality of the unit. It is simple and staight forwad to use. The tumbler is robust and it never leaks. There are instructions with the unit. I have bought other brands, had issues with leaks and failures after weeks. Another brand even melted. I am very satisfied with the quality of this unit and their customer service.

I was so happy after buying one of these machines and using it for a month, that I bought another. Unfortunately, the second machine came with a bad AC adapter, but I contacted KomeStone's customer service department, and Lily was able to help me out right away. I received the replacement adapter just a few days later, and the second machine has been running great ever since. The first attached image shows a batch of rocks that has been through the whole process, mostly including rocks that were included with the tumbler. The second photo shows a batch of rocks, which I found myself, that are at the end of the second of the four tumbling stages. I'm reserving them while I process some more stone through the first two stages. KomeStone and others recommend making sure that the tumbler is kept 1/2 to 2/3 full during each of the stages for best results. Since the stones get smaller with each stage, it's likely that even if you started with the tumbler almost 2/3 full at the beginning of the first stage, by the time you get to the end of the second stage those same stones are unlikely to fill the tumbler the requisite 1/2 full (or 1/2 empty, if you see it that way). So you'll always be running more stones at the earlier stages than at the later stages. You're also likely to find that some of your stones have cracks in them after one of the stages that makes it a good idea to either rerun them through the first stage to really smooth out the larger features, or just enjoy them as they are, without further processing. Keep in mind that you will need to buy more grit to process additional loads, but it's relatively inexpensive. You'll need to buy more ceramic filler, too. After two months, the filler in my initial jar has shrunk to the size of grains of rice. I recommend pressing firmly all the way around the top of the barrel, once you've put the metal cap on, but before you screw it down, just to make sure that its seated as squarely as possible. That can help prevent unfortunate leaks. Also, if you're sensitive to noise, you can save yourself a headache by buying a 5-gallon plastic bucket and inverting it over the top of the tumbler while it's running. Just one bucket per tumbler meant a significant noise reduction, although I found that two is even better; so much so that I can keep the tumblers in the room with my computer and have a videoconference without any problem. And you can always use the buckets when you go out to collect more material for tumbling. One more thing. Tumbling is a process that requires patience. I run each stage at the maximum recommended length, where the four stages take a total of 31 days, and it's even longer when you factor in the multiple early stage loads it will take to a properly filled final stage. If you don't have that much patience, it won't be terrible. I ran my first batch all the way through from stage one to stage four, even though the latter stages were less than 1/2 full. And the results still look pretty good. It's not like I'm wanting to sell them or anything.

I was so exited to get my rock tumbler, started the first cycle and went to open the barrel and the lock nut welded itself shut and I cannot open it. Now my rocks are stuck in it and I have to cut the barrel open. 😞 Update.... the company sent me a new tumbler as a replacement and the new one works perfectly. Thank you for the quick response and replacement.

Seeing a LOT of complaints from the past two months about motors failing. Guess what? Mine stopped working today, have only had it since December. It ran strong for those two months, then today after I took off a batch of tumbles, when I went to put a new batch in, it doesn't tumble. Display lights up but the motor is cooked. I Emailed their "24/7" customer support" so I'm hoping I actually get a reply. Sounds like Komestone needs to provide better, durable motors if it wants to stay in business, because this is clearly a chronic issue, and this is supposed to be the "upgraded, Professional" model. UPDATE 02/26/2026 - I initially didn't get a reply from Komestone support when I Emailed them, but I suspect it got filtered and never made it to anyone. I used the "request a free gift" QR code and through that I got a fast reply from customer service, where I was able to explain my situation. The rep was very friendly and helpful and arranged a brand new K1 Pro to be shipped to me at no cost, since it was within the warranty period but outside of Amazon's return window. I got the new unit today and confirmed everything is working, so I've revised my review to five stars since the company is making an honest effort to uphold their warranty. Hopefully this new one will last longer. UPDATE #2 03/09/2026: The replacement unit died on me after one full tumbling cycle and a few days on the next. The motor STRUGGLES with any kind of load on the tumbler, even an empty barrel, and only starts spinning the barrel for a few seconds at best before it locks up. The "cutting-edge" motors they are using in this unit are trash. I moved the loaded barrel over to a different brand tumbler base that is rated for a lighter load and it's tumbling it just fine. This is ridiculous. UPDATE #3: The saga continues. KomeStone support sent me new motors which appear to be from a newer production run, so here's hoping they don't suffer the same fates as the previous ones.

The Tumbler works great! Keep the tumbler clean to make sure it operates well after use as the grit and dust will cause issues The belt will wear and tear after a few tumble which is normal. The great thing part is the customer service of Komestone. They will provide you with 5 free belts!!