DIY Rock Tumbler Made From Scraps

Earlier this week I had to do some plumbing and I bought some extra supplies that in the end, I didn't need, so I decided to make a tool I have not had for a long time and that is a rock tumbler. I tried to make it as simple and robust as possible, so I used some old cutting boards that I found in the attic, which are quite thick and strong and a perfect material for making housing for electronics. The only thing that is not commonly available are the gears that I picked from my scraped 3d prints box, I planned on using them in another project but in the end, they just got thrown in the random stuff box. I also found some small furniture wheels from an old failed project.

Upfront I'm sorry for any grammatical errors and poor quality photos as this is my first instructable project.

TOOLS

1. A Dremel or a drill, with various drill bit sizes

2. A jigsaw or a table saw

3. Tap and die set, you will need the Taping bits only

4. Soldering iron

5. Screwdriver set

6. Sanding paper

7. Sanding attachments for Dremel are highly suggested to shorten the time needed for sanding.

SUPPLIES

1. Two 11cm PVC plumbing endcaps

2. One 11cm PVC plumbing connector

3. One 8mm threaded steel rod(They can be bought at most hardware stores)

4. Old Mobile phone charger

5. Electric motor with gearbox( i found they work the best with heavier loads in the drum)

6. 4 small furniture wheels

7. 8 M4 screws

8. Some wood screws

9. Two old cutting boards

10. 2 M8 nuts

11. 2 Gears ( can also be made from wood, but may take some time and precision. I suggest buying some if you don't have the tools to make them)

12. Electrical wire

13. Solder

14. Switch

15. One M3 screw

16. 10 and 13 combined wrench

17. Hot glue gun

Mark the center on both end caps and drill thru them, Tap them afterward with the tap and die set. I suggest using a smaller drill bit first then step up the size. The hole diameter was around 8mm, so make the threadings while the hole is around 7mm in diameter, as doing it after will have no effect. In this pic, I used Dremel as I had that on hand.

Press one of the endcaps into one of the ends of the connector, and remove the rubber seal on the other end. Removing the rubber seal is a must as most plumbing connectors are rated up to 8 bars, making removing the main cap almost impossible. ( Believe me, I accidentally plugged the wrong end and ended up using a press to unplug the end cap) NOTE: It might take some force to plug the end with the rubber seal

Tap one of the gears so it can be screwed right onto the 8mm threaded steel rod. Cut the rod to the right length( it was around 22cm in my case) using the Dremel and some cutting discs. Tap the other gear so an M3 screw can pass right thru it.

Thread the rod thru both end caps and capsule body, try making it as even as possible on the sides.

Screw on the gear with 8mm thread on the sealed end cap, fix the gear to the end cap with an M8 nut. (this is the capsule part which should be hermetically sealed and will not be removed later)

To finish the capsule assembly put the end cap without rubber seal on the opposite side and fix it with an M8 screw( Be aware this is the main hatch of the capsule so don't make it too tight as you might have some warping issues in the future, and it has to be easily removable)

Mark the cutting lines on both boards. (make sure both of the boards are similar in size) Cut just the tail on one of them and cut the other one in 4 parts, out of which make two shorter for the thickness of the board to make it easier to assemble. Make a slot for the switch. Sand every wood part to remove any splinters and sharp edges that may occur during the cutting.

Mark the desired roller position and its mounting holes. Drill the board with a 3mm wood drill bit, and tap the holes with an M4 bit. (The hole has to be smaller so the tapping bit can cut threads into the wood)

Screw on the rollers using M4 screws. And test if they align with the capsule. Screw the lower portion made from 4 cutout planks together. Be aware of the switch notch orientation as it will decide how much wiring you need to get through the housing.

Screw the gear with an M3 screw to the gearbox shaft and make there is as little play as possible. Make a simple circuit with the switch, motor, and old phone charger it should look something like shown in the photo. Solder everything together I suggest using thinner more flexible wire as it leaves a much smaller trace on the final product.

Glue the gearbox to the housing in such a manner that gears collide with each other as shown in the photo. Pull the switch thru the pre-made notch and glue it. You can paint the capsule and add wood lacquer to the housing to make it look nicer, also an easy upgrade is making a shaft holder for the capsule from the leftover cutting board tail.

You can tumble all kinds of stuff in this little guy, ranging from glass to make sea glass to add a finish to your blades. As it's small in size and uses normal el plugs, you can bring it with you almost anywhere. To use the tumbler open the capsule on the side that has no gear and rubber seal, put your desired abrasive medium in it and the item you want polished/sanded, put the capsule onto the housing in such a manner so gears intersect with each other, and fire it up. Watch it work. It may not have the best looks but never judge a book by its cover.