Dave - if we are going to get into the engineering perspective,
let’s talk about how far the steel moves to burnish the piece. In a
vibratory tumbler, the steel never really tumbles, it slides over the
work. In a rotary tumbler, it actually drops onto the work pieces.
Compare to a hammer planishing - it isn’t going to do much at 1/16"
compared to an inch. If you want to slide stuff, do it with ceramic
beads, it’s cheaper by far than steel.
Further, on the maintenance and care - yes I must oil the pillow
block bearings occasionally. My barrel is steel, doesn’t leak, and in
twelve plus years, my belts have not broken nor do they appear worn.
I have however had two vibratory tumblers fail completely at the
Christmas rush. If my rotary failed, at the worst possible time, I
would buy a new belt at the auto store and be back in business the
same day. The vibratory tumblers require total replacement.
Here’s something you may not have tried. When mass finishing to a
high polish, first run your jewelry in steel for 30 minutes, then in
the abrasive media for the normal cycle, and finish in the steel
again in your rotary tumbler. The work hardening done in the rotary
tumbler changes the crystalline structure of the precious metal
surface so that the smoothing of the abrasive media is more even and
the final burnishing is top rate. For a perfect shine, run more step
in a vibratory tumbler with dry media charged with simichrome for 24
hours. It results in a better finish than you can achieve by hand.
I don’t know how your vibratory tumblers failed but I’ll share this
as it may help someone. My vibratory tumbler quit and I thought I was
going to have to replace it. When I really looked into it, I
discovered that the bolt/nut securing the eccentric weight had
vibrated off. Fast, easy repair and cheaper than I could have hoped.
Amery -The name of the book is “Tumble Finishing for Handmade
Jewelry” - Mass Finishing on a Small Scale. Available from most
jewelry suppliers.
Vince -The rotary tumblers that I have used are Lortone for the
smaller size like QT6. They use a rubber barrel with a metal lid. The
lid is a nuisance to get off, but was always secure. The rating is
based on its initial design for tumbling rocks. For a small shop, or
a shop with little jewelry pieces that works fine. They are the
simplest of machines - a motor, a pulley with a belt drive and two
rotating bars that the barrel sits on and turns. You can see that
model on the lortone website. I got that initial rotary at a used
tool shop in lower downtown Denver before it became a place of fancy
restaurants and expensive lofts. I think I paid $25 and it had two
barrels. The QT6 is available pretty much everywhere for about
$150US.
Since much of my work is larger than would move easily in that
smallish barrel, I got a bigger rotary in 1998. It has a steel drum
with a rubber liner. It holds absolutely gobs of steel, is heavy when
loaded, and does an absolutely awesome job. I can run 20 to 30
anticlastic bracelets at a time in it. I don’t think the model I have
is made anymore, but it closely resembles model C20 in the commercial
tumbler section of www.lortone.com . I run mine with about 30 pounds
of stainless steel. I should probably wear steel toe shoes when I’m
moving it around. This one runs $580 from Lortone.
Most of the time I could do with a medium sized rotary, but I really
don’t want more equipment and sometimes I really run a lot of big
stuff and need the large drum.
Maybe you can get a better price by looking around.
I have two Dillion Precision, they sell reloading equipment, but have
great vibrating tumblers. I 1 Thumblers Tumbler on hand also, the
medium tells me which one and how much for each material.