I'll tackle part of your question since I have first-hand knowledge
of it... the grinder --> polisher conversion.
I got a grinder for $29.99 at Costco. Removed the grinding wheel on
1 side and replaced it with a tapered mandrel (available from Rio,
Metalliferous, 47th St. Jewelry Supply, and others). Then purchased
a $19.99 shop vac and an extra air filter for it.
I took an old 3-drawer nightstand and bolted the grinder to the top
of it (perfect height for use while sitting, and each drawer holds
its own set of compound, buffs, and finger protectors, which makes it
even easier to avoid picking up the wrong one!). The cannister of
the shop vac sits behind the table on a cinder block, which raises it
to the perfect height. The shop vac's hose goes to the 5" wide
t-shaped tool that came with it, which I drilled 2 holes into and
bolted to the top of the nightstand just behind and below where the
tapered mandrel is.
Now comes the creative part. I use a cardboard box that is just the
right size as the "cabinet" for my homemade dust collector. This let
me cut out the perfect shape for that 5" hose tool and for the side
to allow the mandrel to pass through. I cut a piece of old window
screen about 1" larger on all sides than the hose tool, to keep
pieces from getting sucked in to the vac. The window screen is
duct-taped securely to the opening in the box. Once I got it all
perfectly configured, I covered the entire box with duct tape,
providing a sturdier surface and one that is easier to clean, then
screwed the box down to the nightstand. If I need to replace the
box, it's pretty simple to do so, but you'd be surprised how sturdy
the configuration is.
The draw from the shop vac is significant and sufficiently powerful
to handle the vast majority of the dust from polishing. (Even when
I'm using a "real" polisher with a "real" dust collector, by the way,
I use a clear face shield which also acts as a dust deflector.) I
clean the screen as it gets clogged by lint and dust, just as you
would with a real dust collector cabinet.
So I figure with a little elbow grease and ingenuity, my entire
polishing setup cost me about $55 - 60 total, and I still have access
to 1 grinder wheel on the polisher. I simply couldn't afford a
professional dust collector cabinet (a couple of hundred!) at the
time I put mine together, and it's worked beautifully for me... so I
don't see any need to change it at this point.
Hope this helps a bit!
Handcrafted and Unique Artisan Jewelry