Rotary Tumbling

Since I began making reels in 2011, I have been using a vibratory tumbler to finish parts. This is effective for aluminum and brass reel parts when used with”plastic pyramids” media. A typical part would get 4 hours of vibration, and then would have a dull finish which was easily brightened by manual work with fine grit wet sandpaper. The main function of tumbling is to uniformly remove sharp corners left on the machined parts.

About a year ago, Reelmaker Anders bought a rotary tumbler and told me that it was an improvement over vibratory tumbling. Rotary tumblers are used by ammunition reloaders and jewelry makers. They differ from rotary rock tumblers in that they run at higher speed and use stainless steel media.

So I have recently bought a rotary tumbler, the “Platinum Series” by Frankford Arsenal.

The barrel is big; it has a 4 inch diameter opening at each end and a volume of 1.5 gallons. It also has a built-in timer. Tumbling is done wet; you nearly fill the barrel with water.

This tumbler is marketed to ammunition reloaders and comes with 5 pounds of media which are stainless pins of .040 inch diameter and 0.27 inch length. I felt that this was not the right thing for reel parts, so I have substituted a “jewelry mix” of 5/32″ balls, 5/32″ ball-cones, and 1/8″ diagonals.

I have been running parts 2 hours and getting the same sharp edge relief that I got from vibration. Further, the parts are bright right out of the tumbler and I can run more parts at one time.

Update 23 Dec 2020: The stainless media is good for bronze and steel parts, but not so for aluminum. It is a matter of density: Solid aluminum 0.10 lbm/in^3, solid bronze 0.27, solid steel 0.28, stainless media 0.18, plastic pyramids 0.03. An aluminum reel spool will “float” on top of the stainless media and not get well polished. It gets worse as you add more water to the mix because that makes the aluminum part even more buoyant. So for aluminum I am using a product from Surf Tumbling Media. It is “Green Plastic Tumbling Media General Purpose – Deburring Pyramid Shape – 1/4 inch”. My tumbling barrel is sufficiently filled with a 2.5 pound bag. Leaves a nice matte finish so the anodized spool is not reflective.

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7 Responses to Rotary Tumbling

  1. D Profota says:


    Thanks for all the information you have provided on your blog.

    Is your jewelry mix a stainless mix? Do you think the same jeweler’s mix would work to polish and deburr 6061 aluminum?



    • dave49 says:

      All 3 shapes that I bought are 304 stainless. I make reel spools from 6061 and am using this tumbler on those, as well as on the brass frame parts.

  2. Greg McGowan says:

    Dave: Where did you purchase the jewelry mix you describe? Thanks for the update. Am building two of your plan reels right now and have found the drawings to be flawless to this point. They have really helped. Met you at Lovells at the Grayrock Bamboo gathering. Greg McGowan

    • dave49 says:

      I made the mix myself from 2.5 lbs balls, 1.5 lbs ball-cones, and 1 lb diagonals. These all came from the Ebay store ToolSupply. This vendor also operates as the web store

      . Go to the category “Tumbling Media” to find 304 stainless material. Some of the other Ebay vendors are selling 302 stainless material. I think that 304 is better; it has better corrosion resistance.

      Update 4 Oct 2014: I now think that the comment that I made about 302 vs. 304 stainless is incorrect. I had 302 confused with 303. Grade 303 has sulfur added to promote machinability, and this compromises corrosion resistance. All 3 grades are “18-8” stainless. As far as I know, 302 and 304 are comparable in corrosion resistance.

  3. Fred Balling says:

    Dave. By way of comparison, my nickel silver elements are run in an industrial vibrator with triangles and pyramids of erodible plastic with I think white rouge embedded. The result is
    a smooth crystalline frost-like surface which I then polish with felt buffs on dremel.

    Next reel up will have aluminum faceplates that I hope to age and anodize to look like the
    old hard rubber (ebonite) of vintage reels. I am guessing that sandblasting beforehand can get me a controlled uneven surface similar to castings or an old leather sole. Might even require etching.
    Do you have any suggestions or recall any accidents that might be applicable?


    • dave49 says:

      Sounds like we have used the same plastic pyramids, but I put them in a small vibratory tumbler that reloaders use. The resulting surface shines up with little effort.
      I don’t know anything about any aging process and so cannot comment there, but I do home anodizing regularly and have posted details in this blog. You might find lye (drain cleaner) in warm water to be an effective etch. I use it to remove an anodize layer if I want to do it over again.
      I have tried dyeing the anodize layer (before sealing) but found it difficult to get a uniform color, other than black. I have been using electrolytic coloring to tone aluminum parts, and have posted the details. I understand that if the coloring process is run long enough (I only run for 5 minutes) then the color becomes almost black. But at that point, the anodize layer pores may be nearly filled with tin and sealing may not be effective.

      • Fred Balling says:

        Thanks for any and all intelligence on this subject. Black is where I am going, sort of semi gloss with some pimpling and pitting as a nod toward the the Ebonite used by the masters back when.
        I love Ebonite, but it is tough to finish and polish, and my collector guru guy tells me the
        buyers consider it to be “plastic” and don’t want to pay the premium. Go figger.

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