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Tip 26: Vibrate Your Powder
I know this seems contrary to everything you’ve read thus far in this “Tips” file. But it has been demonstrated
that inducing some constant and consistent vibration into the powder measure can yield more consistent powder
drop weights. The difference is that these vibrations are controlled and targeted. Here is how it works.
All gunpowders are granular (albeit in wide variety of shapes and sizes). As such there is a lot of air space
between the grains. If you vibrate the powder, it will settle and eliminate some of that air space. Continue
vibrating the powder and you eventually reach a point where the grains are as tightly packed as they can
possibly get. If you can achieve that within the metering chamber of your powder measure, your powder drops
will become very consistent. This is similar in concept to the “Powder Knocker” on the Lyman #55 Powder
Measure (see Tip #7) but is a continuous vibration rather than a few well-timed knocks.
Around 2005, Bob Coval conducted some rather extensive research on settling powder to achieve more
consistent powder drops. His research resulted in the “Coval Device”. It was simply a small DC motor with an
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eccentric weight packaged inside a plastic tube and powered by a 3VDC power supply. It
strapped to the side of your powder measure using a rubber band and had a piece of foam
glued to the side to help stabilize it against the irregular shape of the powder measure. It was
on continuously as long as the power supply was plugged into a wall outlet. I tried one but,
in my opinion, it shook the powder measure too violently and was very noisy. I think the
frequency needed to be higher and the amplitude lower. Plus, it really needed a mounting
method that was better than the included rubber bands, and an On/Off switch. Alas, Bob has
passed, and the Coval Device is no longer available.
Meanwhile, there are many forum postings about using aquarium air pumps, pager motors,
buzzers, alarms, ringers … and even adult toys to induce vibrations directly to the powder
measure. Aquarium pumps seem to be a favorite as they are inexpensive (as little as about
$6.00) and easy to find (most pet stores, Walmart, Amazon, etc.). You can even find battery
powered air pumps. Regardless, you’ll want the smallest one you can find as they are
usually strapped to the side of the powder hopper tube. Ideally, it should be attached as
close to the powder metering chamber as possible (like the Coval Device). But even the
smallest aquarium pumps are too large to mount there.
Everyone has a chuckle about this, but egg vibrators from an adult shop can be an effective
option. They are small enough to mount directly onto the side of the powder measure (like
the Coval Device), placing them as close as possible to the metering chamber. Most have
variable speeds and some even have different vibration patterns, so you can experiment to
determine the optimum setting for your powder measure and the powders you use. And
they cost only a little more than an aquarium pump.
Here is my setup.
