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[Archive Post] Length of metal required for ring


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From: “Guy Payton”

There is “The Jeweler’s Bench Reference” by Harold O’Connor “The
Complete Metalsmith” by Tim McCreight - a must IMOP

To specifically answer your question:

Formula: inside ring diameter + metal thickness x 3.14

Size 7.5 US = 17.6mm + 1mm (18 ga.) x 3.14 = 58.4mm

That’ll give you the ring blank length.

Hope it helps,

From: “Dave Sebaste”

Hi Sarah, As you can see from the table below, the length of the
blank you need to make a ring of a desired size depends on the
thickness of the metal.

Ring blank lengths in millimeters:

Size		16ga.		18ga.		20ga.
3			48			47.1		46.5
3.5			49.3		48.4		47.7
4			50.6		49.6		49
4.5			51.8		50.9		50.2
5			53.7		52.8		52.1
5.5			54.3		53.4		52.7
6			55.6		54.6		54
6.5			56.8		55.9		55.3
7			58.1		57.1		56.5
7.5			59.3		58.4		57.8
8			60.6		59.7		59
8.5			61.9		60.9		60.3
9			63.1		62.2		61.5
9.5			64.4		63.4		62.8
10			65.6		64.7		64.1
10.5		66.9		65.9		65.3
11			68.1		67.2		66.6
11.5		69.4		68.5		67.8
12			70.7		69.7		69.1
12.5		71.9		71			70.3
13			73.2		72.2		71.6

I’m not sure of the original source of this data. I copied and
pasted from a spreadsheet I acquired somewhere. This is
also available in a variety of books, and I have not cross-referenced
this data for accuracy.

All the best,
Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery

From: “Karen Goeller”

Sarah, There’s an excellent chart in Oppi Untracht’s book (Jewelry:
Concepts and Techniques) to calculate the length of metal required
for a ring blank based on ring size, gauge of metal being used, and
width of the band. That book is the “bible” of jewelrymaking and is
well worth the investment!

Good luck!
Karen Goeller

Charlotte, NC (USA)

From: Jerry & Norma Holt

Sarah, The length of stock required for a particular size varies with
the thickness of the metal. There are tables published in lots of
books. One that I would recommend highly is Alan Revere’s excellent
work “Professional Goldsmithing”. Not only do you get the tables for
ring blanks, but also some really great instruction in the
goldsmith’s art. Jerry in Kodiak


Dear Sara, For charts on cutting ring blanks along with many other
useful charts and formula’s, my favorite book is Professional
Goldsmithing by Alan Revere. I use it so often that the pages are


From: “Bill Seeley”

Metal Techniques for Craftsman by Oppi Untracht has a chart.Page 461
The Theory and Practice of Goldsmithing by Prof., Dr. Erhard Brepohl
Page 501 Note that they give dimensions but not how they relate to
thickness. The length will change according to the thickness of the
shank. Bill

From: kpkelly

Check out “The Jeweler’s Bench Reference” by Harold O’Connor. It’s
68 pgs and has what you’re asking about and more.

From: Pat Topp

HI! Sure, there are available paper test ring sizers. I think I got
mine through Rio Grande. It is a flat paper strip with sizes on it
to check customers ring size which I can just send to the customer so
they don’t have to come to the shop. You could just leave it flat on
your bench and take the measurements from that. Don’t forget about
the gauge of the metal. There is a formula given in many books I
can’t remember which right now. Pat DIACCA Topp

From: “joanna gollberg”

in murray bovin’s book, “jewelry making for schools, tradesmen, and
craftsmen”, there is an excellent visual chart for ring sizing. i’ve
photocopied it and laminated it and keep it in my bench for easy
measuring reference. take that length (in mm), then add on
approximately 1.5 times the width of the metal you are using for the
band. joanna gollberg


  Is there in existence anywhere either in the net or in a book on
some lovely fellow jewellers shelf - 

Professional Goldsmithing BY Alan Revere A Great Book can be had from
his web sight has many other
useful formulas.

From: Peter W.Rowe

   Is there in existence anywhere either in the net or in a book
on some lovely fellow jewellers shelf - a guide that tells you the
length of metal you need to make a certain ring size e.g K?  I
have struggled for a while making thins for people, using wire
around their finger etc etc, but to no avail.  Im sure there must
be a reference somewhere as to the legth you need? Can anyone help? 

You can find charts on some ring mandrels, a very complete set of
charts in Kunths reference book, which is nothing but charts and
reference info, and in any number of other sources, including handy
little charts printed on sheet metal you can stick to your bench
edge, etc. But all you reall need is a calculator with the pi
function, or the patience to type in that figure (3.14159) then do
this: Measure, accurately, with a dial caliper, micrometer, or
digital caliper (easiest, but make sure it’s accurate) the diameter
of the ring size you need by measuring that marking on an accurate
ring mandrel. To that measurement, add the thickness of the metal
you’re using. multiply the result by pi, and you get the length of
the blank needed. This method is more accurate than charts, since it
calculates the blank needed for exactly the thickness of metal you’re
using. It’s easiest using metric measurements. it’s also the easiest
way to figure the length of bezel wire to make a bezel, especially
for round stones. Measure the stone diameter, add the bezel wire
thickness, multiply by pi. There you are. For oval stones, add
the length to the width, divide by two, for the average diameter, and
proceed from there. Oval,s however, vary in circuference sometimes,
if they are not a mathematically correct elipse, so the the method
can be less accurate with ovals.


From: “Michael David Sturlin”

Alan Revere has an excellent chart in his book “Professional
Goldsmithing” which lists accurate measurements for blanks according
to ring size and the thickness of metal being used. This is one book
I highly recommend, a very worthwhile investment. Order it online at or call 415-391-4179 for more

Michael David Sturlin, jewelry artist
Michael Sturlin Studio, Scottsdale Arizona USA