Author Topic: Magnetic Tumbler, Polishing home brew unit  (Read 15955 times)

Offline PTsideshow

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Magnetic Tumbler, Polishing home brew unit
« on: February 12, 2010, 04:50:24 PM »
Might come in handy for people doing non ferrous small parts on the forum.
Here is 5 pages of plans and instructions for a shop made magnetic tumbler

It should be a easy project for members here.
This is a video of a different one a lot cruder, notice what he is using for a disk to hold the magnetics.
a video of a different style home brew finisher

The following are in case anybody needs a spot to get the other parts. The evaporative cooler motor is based on the use under the water filled bowl filled with spinning stainless steel tumbler pins. The pins are magnetic to make them easier to separate from the jewelry or other non ferrous items.

a neat place for parts, she was very pleased with the help and service
A lapidary/grinding sanding polishing equipment maker dealer.

If you can't find a bowl or container here is a place that will have something.
great place to deal with I have been a customer for 25 years

The pins can be had from most jeweler supply houses
Contenti
Gesswein
Otto Frei
Metalliferous
Grobetusa
RioGrande

They can cost $1,200 and up  from supplier, or $120.00 or less depending on what you feel like making up.
 :dremel:
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Offline snub

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #1 on: May 26, 2010, 01:09:04 AM »
Thankyou for posting this, you have definately piqued my interest.  I built a homemade vibratory tumbler but found out that you need to vibrate the media for 24 hours just to get it " broke in", but the parts need to vibrate for 24 to 48 hours to get a decent finish. No way I am leaving a motor running for 2 days...unattended. Don't need to burn my shop down.

So this magnetic tumbler (according to one of the websites you linked to ), will do the same job in 30 minutes.

I read the 5 page 'how to' and watched the video. They both say that the magnets need to alternate in the circle, from north pole to south pole, or positive to negative, but neither one tells you how to determine the poles of the magnets.

Also, I snatched this from the 'how to'...Not sure  what he means. There are only 2 dimensions on a circular object, width and height. But he adds " 30 or more". Me confused.



He also neglected to add the "pins' to his parts list. The first link you gave showed 2 diameters of pins, at 1/2 pound for $29.95. What would be a good amount to start with for 'experimenting'?

Offline No1_sonuk

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #2 on: May 26, 2010, 07:57:04 AM »
Also, I snatched this from the 'how to'...Not sure  what he means. There are only 2 dimensions on a circular object, width and height. But he adds " 30 or more". Me confused.

That says 30 or more MGO, which (I think) is a definition of the magnets' strength.

Offline Bernd

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #3 on: May 26, 2010, 11:24:49 AM »
I read the 5 page 'how to' and watched the video. They both say that the magnets need to alternate in the circle, from north pole to south pole, or positive to negative, but neither one tells you how to determine the poles of the magnets.

To find the poles of a magnet you would use a compass. Usally the compass has two colors on the needle. First determine what color is used to point north. Take note of that color. Next slowly bring the compass and the magnet close to each other. See which color is attracked to what end of the magnet. If the color is the color you determined that was north it will indicate the north pole on the magnet.

NOTE: Somebody tell me if I wrote this correctly for easy understanding please.

Quote
Also, I snatched this from the 'how to'...Not sure  what he means. There are only 2 dimensions on a circular object, width and height. But he adds " 30 or more". Me confused.

I think magnets are quote in "GAUSS" for strength. Again somebody correct me if I'm wrong. I did a quick search on the web using MGO and didn't get anything remotley related to magnets.

Hopes this has helped some.

Bernd
« Last Edit: May 26, 2010, 11:44:46 AM by Bernd »
You can't fix "STUPID".

Offline mklotz

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #4 on: May 26, 2010, 11:34:17 AM »
Magnet strength is usually rated in units of Gauss, but MGO can be used as well..
 
MGO stands for MegaGauss Oersteds and can be expressed in a "grade" number that represents the end of an equation that takes into account coercitivity, flux, retentivity, and all the magnetic-related goodies.  It is the maximum energy product of a magnet, and it doesn't really tell the true strength of the magnet.  What it does tell is the quality of the materials the magnet is made out of.  So it is a good indicator or the strength of a magnet.

Google "MGO magnet strength" for more information.
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Offline ScroungerLee

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #5 on: May 26, 2010, 08:02:08 PM »
Funny, one of those jewelry links sells magnetic tumblers for as little as $179.  Small though.

http://www.gesswein.com/catalog/catalog.cfm?catalog=1&cat=9&sub=3&subsub=13

Lee

Offline PTsideshow

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #6 on: May 27, 2010, 08:56:00 PM »
They have summed up the items you asked about, pretty well. Yes some times you do need to have them run what seems for ever.  Again depending on the media you are using in the vibrator or roller tumblers, and the amount of and type of material you are trying to remove.
I have used a electric drive concrete mixer with pea gravel and some larger assorted stones, as the media on some heavily painted cruded steel items. At the time nobody was living in the house behind me, and SWMBO was in Fla visiting her Outlaws.
You could hear it with the doors closed but just that there was something running inside! :bugeye:

If the vibrating times worry you just run it while you are in attendance in the shop. It will take longer but it still is better than doing each one by hand!  :doh:
"The internet just a figment, of my imagination!' 
 
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Raise the Dead!
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and I'm working on the first two!
glen

Offline snub

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #7 on: May 29, 2010, 01:11:27 AM »
Thankyou all for your replies and input.  I had never heard of a magnetic tumbler before PTsideshow posted this thread, so I am curious as to how this works. So, the small magnetic "pins" are swirled about by the magnets, causing them to abrade or polish the pieces of non magnetic pieces in the bowl. I would love to experiment with this this as I have lots of motors and magnets. But before I shell out money for these pins I am thinking I could use some steel 'shot' instead. I was thinking of shot used for shot blasting, or even shot used in shot gun shells. Just an idea since I could probably buy it locally.

After doing some Googleing I found that shot for shot peening is available in a lot of different sizes and  'textures', from smooth to coarse. But only available in 50 pound bags.

One other "what if" that came to mind.....What if I wanted to polish a lot of magnetic pieces, and I used a non magnetic media, such as ceramic balls. Theoretically, the magnetic pieces would swirl about in the media which would not move.


I'm only guessing, so I will build a small version and report back with my findings. Please don't hold your breath waiting for my results, my 'things to do ' list is 6543457 pages long.

Offline PTsideshow

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #8 on: May 29, 2010, 11:54:29 PM »

This is a photo of the stainless steel media used with the soap solution.

This is some 2mm shot that Harbor Freight sells on occasion, to bad they aren't in Canada yet.

I have been told that people have used slingshot ammo, that they buy in bulk for small vibrating tumblers to clean up heavy cruded stuff. I think that the .177 cal BB's would be a better choice as they would tend to get into more areas.

Now you have to understand, the use of pins, or elongated pieces is for a reason, They will move in other motions and directions. The local Jewelry supply sells this assortment as they claim it gives the best finish for the time used. Rather than roll as the shot or BB's or sling shot ammo or the shot gun pellets might just clump up into a large piles.

You want it to tumble to achieve, the action that will clean/polish the material in the bowl. The use of water with a little dish soap/degreaser soap is to remove the scum that comes off the items being tumbled. I have only done small jewelry type items, in a small magnetic tumbler. The same pins and soap can be used in a vibrator also. I have done small parts, nuts and bolts in walnut shells to good results. I run the unit while I'm in the shop. Since I'm not in a hurry I have more time than anything else. But it doesn't take long most times.
"The internet just a figment, of my imagination!' 
 
 There are only 3 things I can't do!"
Raise the Dead!
        Walk on water!
                 Fix a broken heart!
and I'm working on the first two!
glen

Offline snub

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #9 on: May 30, 2010, 01:52:00 AM »

Quote
Now you have to understand, the use of pins, or elongated pieces is for a reason, They will move in other motions and directions.

Thanks for that new info. I did some searching also, and found this:




At the bottom of this page it says the balls don't move. Looks like I will have to shell out some dough for the proper pins. No problem, I love spending money. In case anyone else is following this thread, I just ordered some 1" by 1/2" magnets from an E -Pay vendor ( Magnet4us ). $16.00 for 4 magnets including shipping. Can't beat that with a stick!.

I'm off in search of some cheap 'pins'.

Offline snub

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #10 on: June 08, 2010, 12:43:18 AM »


To find the poles of a magnet you would use a compass. Usally the compass has two colors on the needle. First determine what color is used to point north. Take note of that color. Next slowly bring the compass and the magnet close to each other. See which color is attracked to what end of the magnet. If the color is the color you determined that was north it will indicate the north pole on the magnet.

NOTE: Somebody tell me if I wrote this correctly for easy understanding please.



I got my magnets today and bought a compass. Your method is absolutely correct. Thankyou.

Offline snub

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #11 on: June 21, 2010, 12:11:40 AM »
I've got my magnets and my 'pins', have begun assembly and was searching around for  a bowl.  At the Rio Grande site I found this,and I wen't ........ Hmmmmmm. I wonder what that's about.






" Optional bowl converts your magnetic finisher to effectively use non-magnetic media."


So,I'm guessing, if the media is non magnetic, the spinning magnets must cause the orange disc/tube to spin.It almost looks like it has 'vanes' at the bottom of the disc. Anyone have any idea how this works? I'd love to experiment with it.

Offline David Morrow

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Re: Magnetic Tumbler, Polishing home brew unit
« Reply #12 on: November 06, 2010, 03:17:20 PM »
They both say that the magnets need to alternate in the circle, from north pole to south pole, or positive to negative, but neither one tells you how to determine the poles of the magnets.


You don't need a compass. Magnets will attract to each other North to South. If they repel, they are N to N or S to S.

Start with one magnet and mark either side as "A". Stick another magnet to that end. Pull them apart and and mark the attracting side of that second magnet as "B". Keep using the original first magnet to repeat the process for your remaining magnets. Mount half of the magnets with side "A" facing up and half with side "B" facing up. Half will be North up and half will be South up. Easy peasy.