# Magnetic Tumbler /polisher



## mredburn (Feb 21, 2010)

Ive been wanting to make one of these for some time now, I finally got around to it. This took up most of my weekend. It basically uses a motor with a sanding disc to rotate magnets under the bowl with stainless steel pins in it. The pins follow the rotation of the magnets bumping up against what ever is inside the tub burnishing and polishing the pieces. I acquired most of the parts off Ebay, except the 8in sanding disc. The Plexiglas pieces and aluminum bracing were leftovers. I sent more on the stainless steel pins and screws than any thing else. This polishes down into the smallest areas, cracks etc, finer than the drum polisher i have been using. The third picture is of my old drum polisher it would take 9 - 4inch drums. The magnets are the neodymium rare earth type. 1.5in in diameter and a 1/2 inch thick. I almost went with 2in dia x 1 in thick but even the 1.5 are over kill. It Will spin the stainless steel pins holding the bowl 2inches over the top of the machine. It has a power switch as well as a timer so that I can turn it off before the time runs out if I need to inspect the pieces. It will cut my time to polish parts in half or better. Since my drum polisher used larger heavier shot for polishing it tended to leave planishing marks if left in to long. It also couldn't get down into the recessed areas at all. the dark pieces on the top are left over plexi glued down to keep the bowl from walking off the machine.   Any questions or comments?    Mike


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## snyiper (Feb 22, 2010)

That is pretty ingenious!!!! Great Job is there a tutorial in the works? I think that is a great way to tumble small or larger parts!!


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## mredburn (Feb 22, 2010)

I realized that this wouldn't be of much use to a lot of the people here when I posted it. However It might be something somebody could use.

A tutorial? Hmmm Its pretty straight forward. 

1- Select a motor, Hvac, Blower motors work well. 1/4 hp is overkill your only spinning a disc there is very little load on the motor. I got mine off Ebay for $9.00 plus shipping. Shaft length should be 3 to 6 inches. longer means a bigger box, shorter is harder to work with when mounting the disc, It can still be done. If your motor is not already fan cooled you will need to attach a 4in 110v fan to the box. 1 is enough. (Ebay) I used a Dayton Axial fan #4c656a

2- Decide how your going to mount the motor. It will depend on the style of motor you have. Mine hangs by the studs. I used 4 pieces of angle. 

3- Decide on box size. Mine is 13 inches cubed. If your motor shaft is longer you will have to make it taller. I used 1/2 inch Plexiglas because I had it left over from building my house. 3/4 plywood will work fine. The box will get wet over time as you use it so some thought on how to make it moister resistant Will be needed. Paint, caulk, etc.

4- The sanding disc, I used one from an 8in delta sander. I ordered mine from http://www.ereplacementparts.com/disc-plate-p-86145.html $25.00 plus shipping
You will need to make an adapter to reduce the sanding disc bore from 5/8th to 1/2 in for the motor shaft size unless you have a 5/8th shaft. It will have to be drilled and tapped for 10/32nd set screws. Or find a sanding disc with a 1/2 shaft bore. You can use a 6in sanding disc. without a problem

5-Magnets, I used 4, 1.5wide x 1/2deep Magnets. 1 in x1/2 would work, I tend to over build. They cost me $20.00 for 4 plus shipping from 'Magnetsforless' on Ebay.

6- 1- On/off toggle switch heavy duty rated, 60 min. timer, power light,optional but it looks professional. A power cord. 4 rubber feet. I used a 4inch drain grill from Lowes to cover the 4in circulating fan. Qty. 2-$2.99e. 1/8 plate 4x6 to hold the Switches etc.

7- I used a Cuisinart bowl off Ebay, Any flat bottom bowl with a lid will work. I used the Cuisinart because it has a handle and a column in the middle of the bowl that helps keep the parts out towards the edge of the bowl where the action is. I made a plug for the center of the bowl out of scrap Plexiglas from the cut outs.

8- Stainless steel pins. They are available through jewelers supply but I can probably get them for you cheaper. They are the most expensive At $50.00 for 8oz. that is more than you need.

9- 1 piece of Plexiglas min. 1/4 thick for the top. 

Build and assemble your box and motor bracing, hang the motor, fit the circulation fan if used, cutting a 4in hole on opposite sides. I used a hole saw but a jig saw will work fine. Fit the fan/ hole covers. Cut out a hole out to put the switch plate assembly in. Mine was 3x5.

Hanging the motor; On mine the top of the sanding disc is 3/4 of an inch below the top of the box. The magnets are strong enough you can hold the bowl 2inches over the top of the box and it still whips the pins around. The magnets ore 1/2 so you have 1/4 in of clearance between the magnets and the top of the box. Check the motor for plumb and adjust.

Making the sanding disc assembly; The magnets are held on the disc by making a plywood or Plexiglas disc the same diameter of the sanding disc. Layout your disc with a drawing program or a compass. The plate to hold the magnets should be 3/8 to 1/2 thick. I used 1/4 but there is a chance the magnets can whip out of the holes.DAMHIKT. YOU need 1 1.5 hole for each magnet and one hole for a screw between each magnet. Use a 5in diameter circle for the center of the magnets and screw holes. Exact measurements and placement are critical for the balance of the disc. Drill your holes in the holding disc using a 1.5 Forstner bit on the drill press. I cannot stress accuracy strong enough on drilling these holes.
To center the holding disc on the sanding disc. I bored a 5/8 hole in the center of the holding disc. pushing the 5/8th adapter up through both plates i drill the screw holes through both plates. I counter bored the top plate and threaded the sanding plate but you can just bolt right through both of them. the Magnets will just snugly fit in the holes and are glued/ epoxied to the sanding plate with a thin layer of glue. I used CA.

Once you have the disc made, and the motor hung check clearances and do the final assembly. I would make at least one side and the top removable to be able to work in side the box, thats what I did. The circulating fan doesn't need to run after the main motor is shut off. You will need to attach small pieces on the top around the bowl to keep it from walking off the box from vibrations. 

Cleansing solutions for the tumbler. You can use any burnishing solution from places like THunderbird supply or RIO Grand supply, they make a special solution or powder you can mix or you can use COCA Cola. or what ever brand you have of cola. Pour in about 1/2 (4 ounces of Pins) cover about 1/2in with solution put in you pieces and let it do its thing. I use a micro mesh coffee filter to pour the pins/pieces/solution in to keep the pins form going down the drain. A magnet in a plastic bag to pull the pins off the pieces is handy. Pass the magnet in the bag around the polished pieces and then pull the bag off dropping the pins back in the bowl. 

Thats about it. Good luck and contact me is you have any questions.
MIke


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## turbowagon (Feb 22, 2010)

Cool project.  When you get a chance, post some pics of the polished objects that come out of it.


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## mredburn (Feb 22, 2010)

I will post some before and after pictures this afternoon/evening.   Mike


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## Russianwolf (Feb 22, 2010)

Hey Mike,
   I get what this is for and as I've got my kiln now, I will be looking into these in the future too. But I have to ask, why couldn't you just use the smaller shot in the drum unit? I mean its the shot that's doing the work as long as the container  can hold in the shot and lubricant. Right?


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## mredburn (Feb 22, 2010)

The pins are .5mm x 5mm long they polish by impacting the pieces on the ends of the pins not the sides as the spin around in the bowl. IN the tumbler they would simply rolll around on the sides like a sleeve bearing. The shot used in the rubber/rock tumbler are ovals. football shapes, etc. some are shapeed like Saturn. that way as the roll along the side they bounce around all over the place burnishing the pieces as the do so.  By the way  the cost of a Manufactured unit at this size starts at 800.00 dollars and the american made ones are about 1100.00. cup sized ones are about 500.00


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## mredburn (Feb 22, 2010)

Here is a picture of the pins and the shot for comparison. As you can see they are much smaller than the shot used in the rolling drums.  One of the advantages of the drums however is in prep of just cast pieces using 1/4 in ceramic pyramids. the pyramids remove small surface defects but if left in to long can remove details as well. The pyramids leave a frosty satin surface.


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## mredburn (Feb 22, 2010)

Here is a shot of a piece of cast textured plate the left side had tape over it showing the frosted satin color the right shows where the pins polished the surface. about 30 min worth.


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## inam (Feb 16, 2015)

Hello Mike. Can I use this technique for polishing metal parts?


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## inam (Feb 16, 2015)

I mean mild steel parts.


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## Ed McDonnell (Feb 16, 2015)

I guess you have to buy the right kind of stainless steel or you wouldn't get much movement from the magnets.  I wonder how long that plastic container will last?  Did it show much wear?

Ed


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## Fish30114 (Feb 16, 2015)

I'm not sure what you are polishing, but stainless steel pins for tumbling fired cartridge cases in shooting sports is the Go To method for bright shiny brass and clean cases--even the primer pockets. The most used method is a Thumblers Tumbler--approx. $200 IIRC, and you use a solution of room temp water, a couple drops of Dawn or Joy dishwashing soap, and a teaspoon of "LemiShine, this gets the PH right.

I don't  know what metal parts ya'll are trying to polish, but this method works awesomely on brass cartridge cases. These guys are great to get the stuff for getting going with stainless tumbling: Stainless Steel Reloading Supplies | Tumblers, Separators, Media, Brass & More!


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## mredburn (Feb 16, 2015)

Yes it works well on metal parts. You need to make sure you have enough liquid over the parts and I add Borax  to the soap and water. It makes it silky and produces a higher polish.


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## Charlie_W (Feb 16, 2015)

Very cool! It is great to see folks " need?......make it"! 

Several questions.....
What material is the "disk" on which the magnets are mounted? Does this matter?

Also, what rpm is this disc spinning? Would a dc variable speed motor work? Would varying the speed be of benefit in the polishing?

Thanks!

Now,........just to get it UL approved! :biggrin: you will need 8 warning labels on the power cord!


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## mredburn (Feb 16, 2015)

I have 4 reloading type vibratory tumblers as well as the 9 drum tumbler of all of them this does it much faster. I polish my silver parts. Im still using the same plastic bowl as in the pictures. Its running right now.  
The disk is an aluminum one from a Delta disc sander in my second or third post I had a description and link of where i got it from.  Rpms are 1725  variable speed and reversing help. The small pins get down in the fine details that brushes and wheels wont get to.


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## mredburn (Feb 16, 2015)

I dont know if it will work on steel parts they would probably just spin with the pins.  The pins are 3mm long and .5mm in diameter.


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## Charlie_W (Feb 17, 2015)

Mike, 
Thanks for the clarification of my previous questions.
Now, another question. I am, perhaps mistaken, under the impression that magnets would not pull towards stainless steel. Is this different with this type of magnet or are there different types of stainless?


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## mredburn (Feb 17, 2015)

Not all stainless is non magnetic.  It depends on the makeup. These are made specifically for what I use them for. They are available from jewelry resources.  Riogrande.com is one of them.


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