by John

My model carronade has quite a few very small metal (mostly brass) components.  They are fiddly and a bit difficult to hold while finishing (filing and sanding and polishing).

So I bought a tumbler which is designed for polishing metal jewelry and gemstones, and gave it a go.


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It cost just under $300, including a kilo of stainless steel bits, and some polishing compound.  It is designed to run for weeks at a time when polishing rocks, but I find that 30-90 minutes is enough for my brass parts.




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The drum will hold 4lbs of parts.  Shown here are the stainless steel polishing bits.  The drum revolves quite slowly, about 30rpm.  Water is added so that the drum is just under 1/2 full.


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The before


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after 30 minutes.  It could use another 30-60 minutes of tumbling.  Not all of these bits are for the carronade.


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This is the sight for the carronade.  Complex and tiny and has sharp edges.  Ideal for the tumbler.  The CNC program diagram on the screen.

I am still experimenting with the tumbler.  So far I have used only the stainless steel shapes to do the polishing.  I will try some abrasive compounds soon.  Garnet dust seems to be the commonest abrasive.


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More bits for the tumbler


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A preview.  Almost finished.