By Jeff Brown (New Zealand)
All right then
(strategic pause). So here’s the facts that contribute to the dilemma
I do my fair share
of shooting. A considerable amount of this shooting is carried out
utilizing cast bullets. The combination of the residue from burnt powder,
cast bullet lubricant, sizing lube, general dust and grime and repeated
shooting make my cartridge cases very grubby. Dirty cases are not ideal
as, in addition to not looking very pretty, they are difficult to clearly
detect brass fatigue such as splits in the necks or eminent head
separations in and can be the cause of feeding and extracting problems.
Logically then the most obvious solution is to clean the cases. Short of
sitting down for hours on end with a tin of Brasso and a buffing cloth a
case tumbler is the only answer.
Case tumblers are
dinky pieces of equipment that use a mildly abrasive buffing media
(usually crushed walnut shells) to polish away all the foreign material
that builds up on cartridge cases. The tumbler functions by way of
vibrating the media and cases in such a way that both continually rub past
each other with the end result being shiny brass. Most of the major
reloading component manufacturers make a case tumbler of one size or
another but are quite costly and this is where my dilemma begins.
You see….basically I
am frugal with my money. Some would say mean. It comes from being raised
in Dunedin with all that Scottish influence and having a father who
witnessed the Great Depression (what was so great about it?) first hand.
As such I am always looking for alternate methods of acquiring necessary
items other than parting with my hard earned cash.
If I am too mean
(mean = cheap in New Zealand joe b.) to buy a case tumbler the next best
option is to build one.
Enter Craig. My good
shooting friend Craig is a very practically inclined individual who earns
his crust in the construction business. It was he who first planted the
seed with his mark one model tumbler the materials for which consisted of
simply a 2 liter (1/2 gallon) ice cream tub, an electric motor extracted
from an old fan heater and some lacing wire to suspend it all. He attached
the motor to the under side of the tub, fitted an offset bush to the motor
shaft in order to unbalance the unit and create a vibration, filled the
tub with walnut shells and cases, hung the assembly up and set it running.
In view of how incredibly filthy his .45 ACP brass was (he is famous for
it) a mandatory over night soaking in gasoline was undertaken prior to
treating in the tumbler. The result, after many hours of tumbling merrily
in his basement, was better than factory shiny brass the likes of which I
have never seen in his possession. Had I not seen it I would not have
believed such and simple device was capable of such feats.
Actually, the sole
reason for building the tumbler was than the new barrel he was forced to
purchase for his .45 auto which had a much tighter chamber that the old
barrel. The original factory barrel would not only feed extremely dirty
cases but also feed a full stack of spent cases straight from the
magazine! Now THAT is a generous chamber. Of course the new barrel being
tighter in the internal dimensions was not having a bar of Craig’s grimy
With the success of
Craig’s appliance I thought it would be almost rude not to build one of my
Now, at risk of
offending a good friend it is fair to say that Craig’s mark one tumbler
was not the prettiest device ever created. Actually it was quite
agricultural in its construction though, in fairness, like many pieces of
improvised Kiwi farm equipment (e.g: the Taranaki gate) its simplicity did
not detract from the flawless functioning. The 2 major shortcomings that I
could see with the mark one tumbler were lack of an air tight lid to
prevent dust from escaping and the inability to sit the media/case
receptacle flat on the floor/bench due to the motor being mounted on the
I had a vision of a
free standing arrangement with the vibrating mechanism attached in a way
that it was still able to move uninhibited. The plan would be to build a
box large enough to act as a housing it which the operating components
would sit. There would need to be sufficient clearance between the walls
and floor of the body of the appliance that the container holding the
media and cases could vibrate without touching anything rigid that would
dampen the motion.
To determine the
dimensions of the box first I had to establish the measurements of the bit
that would do all the work would be. I liked the idea of using an ice
cream tub as they are freely available and disposable. The tub would then
need a base to sit on but not be attached permanently to so the two could
be separated for convenience. The base would bolt to the motor, which
would be the source of the vibrations. Allowing for the width of the
bottle the base would have to be 8 inches square and with 2 inches either
side for free movement the box would need an inside measurement of 1 foot
My other passion
besides shooting is mountain biking and as any off road cyclist will
testify there is never a shortage of ruined bicycle tubes knocking around
in garages of respective owners with little or no practical use; or so you
might think. Flattened out bike tube measures about 1 2/3 inch wide. I
surmised that if 2 pieces of tubing were fastened across the top of the
box housing spaced evenly and with a little slack in them they would make
a great support for the base with motor attached to sit in supporting the
tub holding the cases etc. This would allow the motor unit to shake until
the cows came home completely without any dampening.
machine water pump electric motor was acquired from a local appliance
repair agent for the grand sum of $20. These motors are around 75 watts
and small enough not to be too bulky but powerful enough to get the job
done. In order to make the motor create a vibration a weight in the form
of a 170 grain cast bullet was screwed to one of the blades on the fan
that was attached to the shaft which would generate an unbalancing effect.
The motor was fitted to a 8 inches square base made from ¾ inch MDF
(Medium Density Fiberboard) which in turn had a small edging fitted around
the top to hold the bottle securely during operation. All of this then sat
on 2 pieces of bicycle tubing secured with a small amount of slack across
the top of a box also made from MDF. The tumbler was ready for testing.
Initial tests were
very favorable though I could not get my hands on any walnut shells to use
as buffing media. Another friend uses rice as a substitute for walnut so
off down to the local supermarket I trundled and scanned along the bulk
bins. Rice was $2.90 per kilo but barley was only $1.80 so being my usual
frugal self I purchased a kilogram of the barley. Who’s mean? Dumping the
barley into the tumbler with a goodly dose of Brasso the appliance was set
in action. Two hours later I had the cleanest .32-20 brass ever seen.
Later I was given
some walnut shell that has since replaced the barley.
Unfortunately the success did not continue for as long as I would have
liked. The washing machine pump motor was not of the best quality and
during constant operation became very hot at which time the thermal cutout
would kick in and shut the project down. Also, the position of the weight
on the fan blade whilst creating a desirable vibration did nothing for the
longevity of the motor. The bushes began slogging out and the tumbler
began sounding like a skeleton throwing a fit on a tin roof. LOUD? Phewf.
The solution was to
replace the mark 1 motor with a better quality piece with ball bearings
and be more selective about the placement of the weight.
replacement was located which turned out to be 69 watts and though it was
slightly less powerful it was a vastly superior in quality and did not get
so hot or cut out.
I turned up a 7/8
inch long brass bush on the lathe from some 7/8 inch bar and mounted a
long grub screw in it to act as a lock on the shaft and to hold the weight
to unbalance the motor. Tests with increasing weights were conducted until
the desired performance was met. The final combination was 2 flatten .50
caliber maxi bullets that I shoot in my muzzle loading rifle weighing 362
grains a piece. These are mounted on the shaft only 1/2 inch below the
motor housing and within 7/8 inch of the shaft axis laterally. The new
motor is working perfectly and is enormously quieter than its predecessor.
consider when unbalancing an electric motor in this fashion is that they
are not designed to operate like this. Such motors are tuned by the
manufacturer to run perfectly true. By introducing an off center weight
the motor is put under stresses that it is not designed to handle so the
placement of the weight is quite critical as I discovered on the first
sufficiently large weight should be mounted on a short shaft and off
center only enough to achieve the desired result. Similar vibrations will
be able to be generated by placing a lighter weight on a longer shaft due
to the leverage that the extra length of the shaft creates but this is a
double edged sword as the additional leverage will also stress the motor
bearings/bushes more and shorten its life.
The project has been
a great success and one that has cost next to nothing. Admittedly the
capacity of the machine is limited but I can live with that as I will be
only cleaning small batches of .223 and .32-20 brass with the odd few .303
and 8x57. On this subject Craig’s mark 2 tumbler consists of a 10 liter
paint bucket with his trusty motor fastened to the bottom and works very
well and has much better capacity though over heating appears still to be
Aside from the
obvious saving over buying a commercial model I derived a huge amount of
personal satisfaction from the project. It’s a bit like shooting cast
bullets. Using something I made myself. Still doesn’t make me any less
mean though I guess.
Since completion of
the tumbler a server fan from a defunct computer has been added to the MDF
box. The purpose of the fan is to blow additional air over the electric
motor in operation so as to produce constant cooling. This modification
was at nil cost (surprise, surprise!) and appears to be successful. Jeff
Brown, Email, email@example.com