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Larry Jaques[_4_] Larry Jaques[_4_] is offline
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Default Best O ring Material for drive belt?

On Sat, 03 Sep 2016 12:16:44 -0700, Gunner Asch
wrote:

On Sat, 03 Sep 2016 06:13:49 -0700, Larry Jaques
wrote:

On 3 Sep 2016 04:21:12 GMT, "DoN. Nichols"
wrote:

On 2016-09-02, Gunner Asch wrote:
I have a vibratory cleaner...that uses a "o-ring" type drive belt to
power the bowl. Which material type O ring will last the longest?

I use it to tumble/polish cartridge cases. Originally it came with a
"universal" belt..basically a tube and a splice barrel that one cut to
size, and used the splice piece to join the ends into a circular belt.
I ran out of the belt material a few years ago and havent found any
since then. Ive been cleaning up a bunch of cartridge brass...about
100 lbs so far, using some O-rings I had kicking around..but I had to
stretch them pretty far to get them to fit between the
pulleys...which gave them a very short life span. Since Im going to
have to order a bunch of O rings, which material should I be looking
for? The pulleys are in good shape and are of proper half round
grooves...for about a 3/16" round belt.

Look into your MSC catalog. There is a urethane rubber round
belt material (I've got two sizes, translucent orange and opaque green),
which you buy in rolls. I got them to make belts for a Unimat and a
Jeweler's lathe.) Cut it to the desired length, get a piece of material
with a thickness about the diameter of the material, machine a V-groove
in the edge and clamp in a vise to hold it steady. Hold both ends of
the belt in a flame from a propane torch or the like, then squeeze the
ends together, using the V-groove to keep them alligined, let them cool,
and use a razor blade to trim off the flash which will ooze out.

O.K. They seem to be callled "Fenner drive" belts.


Fenner Drive makes that belt, Don. They also make a segmented belt
which can be used in place of a standard V-belt.


For your 3/16" diameter, try MSC catalog number "35364579".
They are asking $97.62 for a roll of 100 feet. Seems to have gone up
since I got mine. :-(


Hmm, it shows up at $70.39 when I pull up MSC.


Secondly...how much tension would be best for this application? How
much stretch should I allow for, when ordering them? Obviously too
much elongation is bad for the belt...what would be appropriate?

With the above materials, you can make them to your needs, so
you don't have to worry about too much stretch. Obviously, the tension
is a function of the load and the speed. Start out by making it just a
very slight stretch and see if it will handle the load without slipping.
If not, trim out the part where you spliced it and try again --
shortening it perhaps 5% or so.


Sounds like a plan!


With too much speed, they will add their own tension, stretching
towards a full circle. But for cartridge tumbling speeds, I don't think
that you have to worry about that. :-)


At what speed does dem li'l vibrators run, anyway? I've never had one
apart. Do they use a wildly imbalanced shaft, like a lady's vibrator
or a phone?

Pretty much it. The bowl is on springs and the out of balance weight
rides on the bottom of the bowl holder assembly...so when the belt
turns the out of balance weight..it transfers directly to the bottom
of the bowl holder. The bowl is 18" in diameter and 6" deep, with a
cone formed in the center so as it shakes..the media and contents
travels both around the bowl and as it travels..it also dives down
from the outside and comes up next to the cone. I dumped half a 5
gallon bucket of .38 Spec brass in it and filled it to within 2" of
the top with crushed walnut hulls and a double handful of 3/8
triangular ceramic polishing media and turned it on. Almost dumps
media out of the bowl..its quite powerful. There are (2) pulleys on
the motor..so I used the smaller pulley as the large one was eating up
my o rings rather quickly (bigger diameter..more stretch) and on the
large motor pulley..it would bring the media up and out of the bowl.

No idea what rpm it runs at..probably 1750.


Fractional horsepower rating?


Rubber crutch tips on
the 4 legs are supposed to hold it in place..but the crutch tips are
hard as a rock with age and it skips across the table top easily..so I


You can get new crutch tips for $3 at Wally World.


put it on a couple bags of lead shot and let the legs settle in..holds
it well enough. But Ill replace the crutch tips..but the legs are
about 1 1/4" in diameter..so finding those will be a trip...shrug


Nah! http://tinyurl.com/hvo4koj

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