Ring sizing to 16?

I just recently started making men’s rings and I have a request for
a size 16 ring. My ring shank gauge only goes to 12 and my ring
mandrel to 13. Measuring the sizes on the ring gauge I see a size 14
is 75 mm and the length increases by 3 mm for each ring size. So I’m
assuming a size 16 ring shank will be 81 mm. Correct?

Rick Copeland – Silversmith
Colorado Springs, Colorado

Rick, how did you determine that you needed a size 16? If you can
measure the finger to a size 16, you should also be able to also
measure the ring. Put the loop that you used to measure the finger
on your ring mandrel and see where it fits. File a nick in the
mandrel here, and you have a match to work to. I wouldn’t be to
worried about your mandrel with the additional mark, as you are not
likely to run into many fingers of that size. The biggest ring I
ever did was about ( I used the above method and could only guess at
the actual size) a size 19. I had to use the small end of a big
tapered mandrel that I have, my ring mandrel were not big enough.
The guy had the biggest hands I have ever seen, and he was only
about 5’10" and 180 lbs or so. Just monster hands.

If you don’t have a loop that size, use a nylon cable tie. Make
sure it is the kind that forms a near smooth interior as it is
closed. Chose one that is about the same width as the ring shank
you want. Start it very loose, and slowly reduce the size to fit
the finger. When you have it at the correct size. cut off the tail
so the size doesn’t get changed by mistake. Just remember you have
to hit the correct size when closing the loop, as you can not make
it bigger once you start. Now find a taper that is big enough and
you are in business.


Not exactly!

Size 16 refers to a size used in Europe. A size 16 ring corresponds
to a 16 mm inside diameter of the ring.

I usually use the formula Pi * (Dia + 2*Thickness of the band)

Using this formula, you will get a band length in the rage 50 mm -60
mm depending on the material thickness.

Good Luck

Imad Abouljoud

Rick, how did you determine that you needed a size 16? 


The order was phoned in by a shop that sells my work. I asked them
twice if they were sure it was size 16.

My 30-year old ring mandrel only goes to size 13 with the handle
being size 14 (my ring size). Since it will be an inlayed ring with
the shank soldered on to the sides of the inlayed piece I can form
the ring shank a couple sizes small then spread it out to hold the
inlayed piece snugly for soldering.

Thanks for the tip on the cable tie. I need to throw a couple in my
jewelry display case. I was checking Rio’s catalog and all their
mandrels go to size 16. I guess our fingers have gotten fatter in
the last 30 years. They also have a jumbo mandrel that goes from
size 16 to 24 for large rings, bezels, and earring hoops. It might
be a wise investment for me as my client says she has a lot of big
biker types looking for men’s rings.

Rick Copeland – Silversmith rick.copeland@Covad.net
home.covad.net/~rcopeland Colorado Springs, Colorado

 Not exactly! Size 16 refers to a size used in Europe. A size 16
ring corresponds to a 16 mm inside diameter of the ring. 

Only, at least according to my sizing sources, in Germany. There
are more than one european standards for ring sizes. Standard metric
sizes (used in 46rance, and i assume some other countries too) are
usually given as the circumference, not the diameter. That means a
size sixteen ring would be something like 5 millimeters across. A
nice jump ring, but not a finger ring. More common are size numbers
like a size 52, which is close to a U.S. size six…

size 16 is indeed also a standard American size ring, albeit a large
one. If you’re stuck with a mandrel that only reads to size 13, it may
help to know that each U.S. size increment is a difference of about
2.5 millimeters in circumference, so start with your blank for a size
13 length, and add 7.5 millimeters to that blank length to get a size

Ring mandrels can be purchased in two usual size ranges. The best
mandrels I’ve found in the U.S., are the U.S. made ones by the Jarvi
company. You can tell them apart (in catalog photos as well as for
"real"), because the handle portion is usually actually knurled for
better grip. The standard Jarvi mandrels go up to size 16 as the
largest size, and then they also offer a “large size mandrel, which
is a considerably shorter but thicker one, that goes from size 16 (I
think. would have to go look to be sure) to about a size 22, if I
recall right.) Many of the tools suppliers carry these, including
Rio, Swest, 46rei and Borel, and others. I seem to remember a price
of about 15 dollars or so. Unlike some of the foreign made mandrels
(often made in India or the like), the Jarvi mandrels are much more
consistent in sizing accuracy from one to another, and are properly
hardened and tempered. Good tools. The last one I bought also
included a little adhesive label with the standard ring shank gauge
printed thereon, since unlike some of the foreign made ones the Jarvi
ring mandrels don’t have that gauge stamped into the mandrel. The
Jarvi mandrels are also available as grooved, and their grooved
mandrel has a slightly shallower, but less deeply cut groove than
the foreign made one. And they also make some specialty versions.
You can buy one quite useful shape that’s the 'rounded square”, or
"cushion" shaped, as well as a sort of egg shaped mandrel. both
these are intended as ring mandrels, not bezel mandrels. Very
useful, though these special shapes are, sadly, not marked in ring

Hope that helps.
Peter Rowe

The step ring mandrel came with a sticker with the lengths for each
ring size up to size 16.  The scale is about 2 mm shorter then the
template I've been using for years.  Is there a published standard
on ring sizes anywhere? 

Chances are your previous guage assumed a usual shank thickness,
while your sticker is likely based on just the circumference of the
ring mandrel at the marked size. To get an actual length for a ring
shank, you have to add an adjustment for the thickness of the stock
used which is normally about 3 times the thickness of the stock (for
flat stock). Lots of the books have charts which may list the actual
diameter of the various sizes. Bruce Knuth’s “Jewelers Resource” has
a good chart comparing many different international ring size
standards to the U.S. sizes. But it only goes up to a U.S. size


Rick, I use the great tables (pages 734 and 735) in Oppi Untracht’s
book 'Jewelry: concepts and technology" and have had great success
with those formulas. They give you the exact size of your ring blank
for USA sizes based on B&S gauge metal thickness. There’s also an
excellent chart with American, British, and European standard ring
sizes, showing the inside diameter in both inches and millimeters.
Between those two charts, you really can’t go wrong.

Good luck!
Karen Goeller