This could possibly be the easiest tumbler ever built. It cost me $0. The 5 gallon bucket, printer (from which I got the roller bars), and the 3 liter bottle came from the trash. The drill was a gift. I'll bet you could do this in about 5 minutes or possibly less. It took me about 10 minutes - but I'm slow! It really does a good job!
Step 1: 5 Gallon Bucket - Almost Any Size Will Do
This is a QUICK and VERY EASY way to make a rock tumbler. It took me less than 10 minutes. I did my best to use the motor from the printer but it was just too fast. I tried to gear it down but all I did was messed things up. I have several motors from microwave ovens that turn the food. I'll give that a try some day but I fear it will be too slow. If any of you have done this, PLEASE let me know. I dont get a chance to get on my computer very often so please, if you leave a comment or ask a question, dont think I'm ignoring you. Also, I didn't check to see if this has already been done. If it has - I'M SORRY. I've been using this for several weeks.
I tumble rocks so, since most containers WILL leak, I used a bucket. I had several 5 gallon buckets so I used one.
If you have ever taken apart a printer/scanner you will have the 2 rods that are needed. One will more than likely have rubber on it. This is what grabs the paper. The sizes vary. You can adjust the height of the holes that you drill for these. The rubber roller bar is the one you attach to your VARIABLE speed drill. Make sure that this bar is AT LEAST level with the other bar. One inch lower (including the width of the rollers) is ideal.
Step 2: Drill Your Holes and Insert the Bars
I know that these are very sorry looking pictures but I did this in a hurry...
I use two containers that are sturdy plastic and have very wide lids. One is 5 1/2 wide and the other is 6 inches wide. I spaced my holes at 4 inches. Be careful... The rubber on my rod is only about 1/4 inch thicker than the bar. I've seen some that have rollers that are about 1 inch thick. Drill your holes accordingly. Start with your roller bar (the one the drill will be attached to) and space your next bar about 1/2 to 1 inch HIGHER than the roller height. My second bar is fixed. It doesn't turn at all. I havent had any problems so far since these are stainless steel rods and super smooth but it wouldn't be a problem to just drill the holes a bit larger.
Step 3: 3 Liter Soda Bottle
I cut this to level the drill (and attached rod) with the 5 gallon bucket.
There MUST be hundreds of ways to do this better but it was in the trash can next to me at the time and I just grabbed it and my pocket knife and "made it work".
Step 4: Finished Product
My pictures were horrible in the first place but they also were "cropped" once uploaded.
Anyway, this is a drawing of the finished product. It does the job for my first step of rock polishing. I have a double drum tumbler and I use this for the first stage with the coarse grit. I bought my tumblers (I have 2 double drum tumblers) from Harbor Freight Tools. I've had them for 3 years and the ONLY problem that I have is that the rubber gasket that covers the bolt plate has worn holes in the center. THAT is why I came up with this, Once the rocks go through the first stage they become more rounded and lose ALL of their rough edges. I believe it was these rough edges that wore out my tumbler gaskets.
One thing to note: This is noisy! I barely hear the rocks tumbling over the sound of the drill. Good luck