Subject: Re: Tumbler rpm

From: Hays/Cash <[email-masked]>
Date: Tue, 10 Sep 1996 22:28:15 -0400

What is a target rpm of a tumbler barrel? (say a 55 gal. barrel) And can I
run it on solar power??

--Doug Hays & Penny Cash
  [email-masked]
  http://hayscash.com

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From: [email-masked]
Date: Wed, 11 Sep 1996 10:44:17 -0700

We ran our tumbler with punchings and cutoff bits at 8 rpm, 12 to 15 
was too fast, it got really unstable, and the centrifugal force kept some 
of the medium from doing it's job, caused the slow rocking back and forth 
that finally upset the whole machine...the noise was incredible.
  Two 2x4's just a little shorter than the width inside were bolted in to 
help the stuff all tumble correctly.  The idea is to get the little 
things to impact the big things, rather than just slide along the walls 
together.
  I geared mine with a wheel drive unit from a center pivot irrigation 
system, bolted a 3 inch sprocket to the output, through a motorcycle 
chain to a 9 inch sprocket on the tumbler shaft, worked perfectly.  Had 
to experiment a bit to get the sprocket sizes right.  We used marble size 
gravel for a while, it worked ok, but disintigrated to dust pretty 
rapidly, so we switched to punchings.  Everything will round off sooner 
or later anyway, and the punchings were free, so we'd use them for a 
couple of weeks, depending on use, and trade for new ones.  Our tumbler 
was designed for railing balisters, 40 inches long or so, and fireplace
tools, but also hundreds of curtain rod rings, and small door handles.
It worked, but our neighbors always complained about the noise!  It was 
really awsome!  The slow speed means you don't need expensive bearings at 
the tumbler ends, we just put the main support/driveing shaft through two 
pieces of pipe and drilled an oil hole in the top.  Still working fine 
after 5 years!
  Bob