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  1. #1
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    Default Need advice about how to grind and polish inside of metal pieces

    Hello all, I'm hoping to get some advice about how to grind and polish the insides of metal slides that I use to make dog collars.metal slides.png
    The collar webbing is lined in satin, so the insides of the metal pieces have to be perfectly smooth. Most of my slides are either solid brass or nickel-plated brass. For eight years, I have used a dremel to grind the inside and then an extra fine file to hand polish the inside. This is incredibly tedious and hard on my hands. More recently, I have run a metal cable cord through the pieces in place of the extra fine file. This is better, but still not ideal. Is there a machine or a better dremel head that will allow me to get a perfectly smooth satin finish on the inside without having to hand file? I've tried grinding stones, rubber, silicon, felt, leather. Nothing gets it as smooth as hand filing. Is there a dremel bit that will achieve the same finish? I will say that I have used the wire brush dremel heads, and they do polish quite well, but they don't last long at all (not even a day's worth of filing) and the wire pieces fly off and get everywhere, including in my skin.

    Also, are there any vibratory bowls that would be able to smooth and polish the insides of the pieces? And if so, would they take off the nickel finish on the solid brass pieces? Any suggestions would be much appreciated!

    Amanda

  2. #2
    BobL is online now Member: Blue and white apron brigade
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    Welcome to the MW forums.

    How many have you got to do?
    If you have Heaps then a rock tumbler/polisher would probably do it for the brass although it would probably eventually take the nickel finish of those with such a coating. You'd have to experiment - there may be grits and fillers that will leave most of the nickel there.

    SHMBO uses a lotto-tumbler vibratory polisher for her stuff (glass and rocks). Depending on how much you are prepared to invest on fillers and various grits etc they can come out highly polished.

    Id look to borrowing one to try it out before you buy.

    Please keep us posted with what you end up up doing as I'm sure others would be interested to see what you come up.

  3. #3
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    I do have heaps, as they're for my business. I'll have to find someone local with a vibratory bowl to see if they'll let me experiment. I'm just worried about the nickel finishing. It would be so fantastic to just drop these in a bowl and let them go for several hours. The hand filing is killing me. I wouldn't even mind dremeling them if I could just find the right head to do the trick.

  4. #4
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    Quote Originally Posted by agtrav View Post
    Is there a machine or a better dremel head that will allow me to get a perfectly smooth satin finish on the inside without having to hand file?
    Hi Amanda,
    There is: https://www.ebay.com.au/i/152562481453?chn=ps
    No need to buy genuine Dremel ones though. There are no-name versions that work well and are much cheaper. They come in different shapes and grits. You may need a few grits to get your desired finish. The wire wheels are nasty things.
    Chris

  5. #5
    BobL is online now Member: Blue and white apron brigade
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    You do realise this is an Aussie forum ? You might be better off approaching a US based Lapidary forum to see if you can find local that will let you try this out on a vibratory tumbler. You are unlikely to stuff up a tumbler machine itself so at most you might have to offer to spring for a replacement tumbler.

    I'd off to experiment with SWMBOs tumbler but she probably wouldn't let me as she treats hers like a baby.

  6. #6
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    Thanks, Chris. I've used the rubber bits before, a bunch of different grits and sizes. They wear down too quickly with the amount of pressure I put on them. Thanks though!

  7. #7
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    Oh wow! I did not realize this was an Aussie forum. That's okay though; it's all the same equipment. I value anyone's suggestions. And I sell a lot of dog collars to Australia too )

    I'll look into jewelry/rock tumblers. I was looking at industrial ones today, but I don't think they're right for my needs. Thanks!

  8. #8
    BobL is online now Member: Blue and white apron brigade
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    Quote Originally Posted by agtrav View Post
    Oh wow! I did not realize this was an Aussie forum. That's okay though; it's all the same equipment. I value anyone's suggestions. And I sell a lot of dog collars to Australia too )

    I'll look into jewelry/rock tumblers. I was looking at industrial ones today, but I don't think they're right for my needs. Thanks!
    I don't reckon you want a rotary tumbler but a vibratory tumbler as they are heaps faster and work much better on off shapes.

  9. #9
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    Have a look here https://www.aussiesapphire.com.au/in...oducts_id=3677 and this company will have the equipment https://www.riogrande.com/

  10. #10
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    Quote Originally Posted by agtrav View Post
    I've used the rubber bits before, a bunch of different grits and sizes. They wear down too quickly with the amount of pressure I put on them.
    Are there burrs on the metal when you start the polishing process? If so, you need to grind the burrs off first with something more aggressive like a Dremel grinding stone. Those abrasive impregnated rubber bits should last ages on brass. You should only need light pressure to polish brass.

    Also, a tumbler is going to remove the nickel plating from the buckles, as they don't discriminate.
    Chris

  11. #11
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    I was working with larger stuff than you are, but anything that will remove metal to smooth and polish the article will remove nickel plating. The normal approach would be to polish before plating rather than after as the plating would generally be a maximum 0.001 inch thick, and it appears that the surface roughness is way more than that. Hence my suggestion would be to buy only brass units, polish them to the standard you require, then have what you need nickel plated. The surface then would be as smooth as the brass surface was before plating.

    We used to use Dremel or equivalent units for mirror polishing into very tight spaces but discovered that their felts etc either wore out very quickly or sheared off. As a cheaper more durable alternative, we used self adhesive felt pad shapes (the ones that you buy to stick under furniture to stop the feet scratching polished floors) stuck back to back and mounted on the Dremel felt spindle. We would just stick the two self adhesive sides together and mount them roughly centred on the spindle then give them a short run against so 60 grit garnet or similar paper to get them fairly true and balanced. Then you need some coarse and fine rouge to use as an abrasive for the polishing. Make up a few wheels at a time and dedicate particular wheels to particular compounds and avoid cross contamination, particularly getting coarser compounds on the wheels used for finer compounds.
    I used to be an engineer, I'm not an engineer any more, but on the really good days I can remember when I was.

  12. #12
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    Default Thank you!

    Quote Originally Posted by China View Post
    Have a look here https://www.aussiesapphire.com.au/in...oducts_id=3677 and this company will have the equipment https://www.riogrande.com/
    Oh wow, thanks for the Rio Grande link! They have a lot of dremel bits I haven't tried!

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