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Finishing Inside Rings


#1

Hi All,

After several years of customer requests, we are finally ready to
start production on our first set of ring designs. I was wondering
if any of you would mind sharing your favorite tools/abrasives or
techniques for finishing the inside surfaces? I am inclined toward
using flex shaft tools but if someone has a really good suggestion
for something that mounts on the buffer, I’m certainly open to that
as well.

Thanks in advance!

Mike Dibble
Black Horse Design
www.black-horse-design.com


#2

Hello Mike:

Depending on how smooth you get the waxes on the inside diameter
will of course dictate what coarseness if emery paper to start with.
I like a split mandrel with Emery paper if I’m doing several castings
at a time on my buffer. Most of the time I only cast a couple at a
time and I use those “3M Aluminum Oxide” sanding bands followed by
Tripoli and white rouge.

Mike Mathews


#3

Mike,

My suggestion for inside of rings is a couple of split mandrels for
the flex shaft and a number of wooden dowel rods wrapped with varied
grits of sandpaper. I use paper from 180 grit down to 4/0. Tape the
sandpaper to the dowel and then secure the ends with either tape or
rubber bands. You can cut strips of sandpaper to wrap around the
mandrels or recycle the less used sandpaper you remove from the dowel
as it becomes worn. Start with a heavy grit paper wrapped around the
split mandrel for quick removal then use the next grit down on the
dowel sanding as you would with a hand file. Continue switching from
flex shaft to dowel, moving down to the next grit on each apparatus
until you have a surface that will accept a tripoli finish (with
silver or gold this will probably be a 400 to 600 grit paper, for
platinum you’ll need to keep going til you’ve reached a 4/0 or 1200
grit finish). By doing this attentively you will never remove too
much, or too little material from the inside of the ring. If,
however, you only use rotary tools you will probably notice that when
you do your final buffing you have lines that run right around the
entirety of the ring. This is caused because it’s hard to tell if
you’ve really taken out all the scratches made by the heaviest grit
paper. But by sanding perpendicularly between grits you will always
be able to tell when you’ve removed the proper amount of metal.

Larry
psychotically obsessed with perfect finishes


#4

If you’re dealing with cast, perhaps rough or textured interior
surfaces such as one gets with waxes that have been hollowed out,
perhaps with a small ball burr or the like, then that surface
finishes very well with the magnetic pin type tumblers. barring
that, sandblast or beadblast also works very well.

For the actual interior surfaces of ring shanks, which normally get
sanded and polished, a couple products for the flex shaft come to
mind. First, are the 3M diamond band sanders. These are sleeves that
fit over a rubber ended expanding mandrel, with the type of 3M
diamond abrasive that looks like lots of multiple little dots.
Available in a wide range of grits. It use first a quite coarse one,
200 something grit, I think, and then a 600 grit one after that. The
bands, if used with a bit of lube (bur life works fine), last a long
time, and remove metal significantly faster than other sanding drums
or tools I’ve tried.20

If you’re working silver or gold, then the fine surface from that
fine sanding band will polish up just fine with standard buffing
motor tools (felt fingers, etc.) If you’re working in platinum, it
may save you yet more time to sand it finer yet, and I recently
discovered an imported sanding drum that amounts to fine sandpaper
wound on a mandrel. Sounds conventional enough, but these are pre
mounted, permanently, on their mandrel rather than the usual
cartridge rolls… Made in Japan, and they use a significantly
thinner and finer paper abrasive than conventional abrasive rolls,
so they run very smooth and true. Last a good long time too. As with
normal cartridge rolls, you peel back the paper as it wears. But the
really neat thing about them is in addition to more usual grits for
cartridge rolls, you can get these things in even very very fine
grits. I use the 400, 600 and 800 grits in particular. The 800 leaves
a surface that you can take directly to rouge if you wish, even on
platinum. Stuller carries them (the diamond sanding bands too). I
think Gesswein does too, and others may as well. In time saved and
better results, they’re well worth the somewhat higher cost over
cheaper abrasives.

And the final little tip I’d pass along is regarding putting the
final rouge finish on the insides of ring shanks. Many polishers use
only the felt finger shaped buffs, and these work well enough. But
the things are rather easy to contaminate with coarser grit, and
sometimes getting a perfect rouge polish, without faint scratches or
drag marks, can be difficult on some pieces. One solution is to get
one of the small mandrels, similar to the type used for the MK
brushes, but that has a fine tapered threaded spindle on the end.
This tapered spindle comes to a fine point, much finer than what’s
on most buffing machine tapered spindles to start with, so you can
mount very small wheels on it. The one I’ve got has a wood hub, which
then mounts on the main spindle of the buffing motor, but I’ve also
seen them in plastic. Anyway, with these, you then can use the tiny
little loose 1/2 inch muslin buffs that normally get mounted on a
screw mandrel and used in the flex shaft. Use these with rouge on the
main machine, and get to hold the ring properly in both hands while
you buff, while not breathing in all the rouge from the flex shaft
use. With these small buffs, unlike the finger shaped felt buffs, you
can much more easily vary the direction of buffing a bit from side to
side, avoiding drag lines, and the softer muslin won’t give you as
much trouble with scratching or the like. Works like a charm. Most
polishers wouldn’t normally consider the finish from a felt wheel,
even with rouge, to be the final surface on an exterior face of a
ring, finishing the surfaces with muslin or other softer rouge
buffs. But many of these same polishers will struggle to get a good
finish on the interior of a ring, not quite realizing that the tools
are there to use the same muslin buff sequence on the inside of the
ring as well.

Hope that helps.
Peter Rowe


#5

Mike,

Well, it depends a lot on what the inside of your rings will look
like. If they are solid, a simple split wooden mandrel with a slip
of 400 grit paper will make a beautifully smooth surface that can
then be polished with a felt inside ring buff. If the rings are
hollow, I usually use my flex shaft with a medium round ball burr.
That makes the hollow part a smooth matte finish and I then finish
the rest as stated above. You might also experiment with putting a
burr into a stationary chuck and move the ring around to shape and
smooth the hollow part…much the same way as carving stone. It
gives better control of the piece and would speed up the process.

Cheers from Don at The Charles Belle Studio in SOFL where we are
awaiting hurricane Frances and where simple elegance IS fine jewelry!
@coralnut2


#6

Just wanted to say thanks so much for all the tips and suggestions
offered for finishing inside ring shanks! I’ll be trying some of
those suggestions on our cuff bracelets as well. Seems like we’re
always looking for something to make life easier.

Thanks again, Orchid rocks! But then, you guys already knew that
didn’t you? :wink:

Mike Dibble
Black Horse Design
www.black-horse-design.com