Anyone build their own vibratory tumblers?

One facet of my shop I really need to work on is deburring. Using a
small rotary tumbler I bought at a yard sale years ago, but it's a pain
to check work in progress and I'm getting to the point of having to run
several loads due to quantities and size. Pricing vibratory tumblers,
they ain't cheap! The nice molded bowls are very reasonable however, as
replacement items through MSC.
At the most basic level, there's nothing much more than a bowl supported
on springs, with a motor and an eccentric weight.
I've got all this stuff sitting around, but before I start on one I'm
curious if there's more to these than meets the eye. In terms of the
geometry of motor size/weight/rpm and spring size/placement, is there
anything critical, or should a tinkerer be able to do this with a minmum
of trial and error? Has anyone here built a decent capacity vibratory
tumbler?

Jon