Question: Ring blank calculator

Chujybear

~ Elite 1000 Member ~
Joined
Nov 3, 2011
Messages
1,079
Location
Haida Gwaii
Hi.
For the jewellers in the house. Potentially a handy calculator.
http://mordent.com/toolsapps/

This calculator purports to figure out your blank length based on gauge, width, and the size you are shooting for.
One thing that is different than the calculation I would usually use is that it adjusts the blank length according to the formula:
If the band is wider than four mm you take the difference, subtract 4,and multiply that number by .5. So (a-4)x0.5. And add that number to the shank.
The way I always heard it was jus across the board +.5 for any ring over four mm.
Neither actually really makes sense to me, because it seems that however wide it is, the middle is still the size that counts... This just seems to be accounting for the extra distance it will have to slip down the sizer.. Which effectively makes it bigger..no? Anybody have insight into this?
I am making a size eleven ring. And measuring it according to the linked calculator, which is adding an extra 1.7 mm to my over all blank length. That seems crazy to me. But if nobody posts an answer, I may be back to St what the results were.
And if anyone's wondering how I've gotten on in life without figuring this out already, it's because I usually do my rings in slate, in the round. But this job needs to be engraved.
Thanks for the help.
 

diandwill

Elite Cafe Member
Joined
Aug 10, 2008
Messages
864
Location
Eastern, Washington State
I have an old Stuller 'Metals' book. It has many wonderful informative pieces that the newer publications don't have. They have a chart for lengths that has adjustments for thickness of the blank. They must also have an adjustment factor for width, but I don't remember...and I'm at home. I'll try to remember to look on Tuesday, if that's not too late.
 

DanM

Elite Cafe Member
Joined
Nov 15, 2006
Messages
203
Location
Minnesota
As far as size goes...depends on where in the world you live. In Europe and elsewhere the ring is sized to the leading edge. In the States and elsewhere the ring is measured to the center of the ring.

ring blank length (mm) = inside diameter (mm) + metal thickness(mm) X 3.14 From The Jeweler's Bench Reference O'Connor 1977
 
Last edited:

Chujybear

~ Elite 1000 Member ~
Joined
Nov 3, 2011
Messages
1,079
Location
Haida Gwaii
Thanks Dan. Lol. That calculation plopped me right exactly in between the two points I've got.
I think I'll go with that, and see how i fair. Less far to go if I have to nudge it one way or the other.
G

I'd like to know anyways , Diane or Will. But I'll hopfully be shipped by Tuesday.
G
 

monk

Moderator
Staff member
::::Pledge Member::::
Joined
Feb 11, 2007
Messages
10,857
Location
washington, pa
As far as size goes...depends on where in the world you live. In Europe and elsewhere the ring is sized to the leading edge. In the States and elsewhere the ring is measured to the center of the ring.

ring blank length (mm) = inside diameter (mm) + metal thickness(mm) X 3.14 From The Jeweler's Bench Reference O'Connor 1977

3.14-- that sounds like our old friend, "pi" takin care of things.
 

oiseau metal arts

Elite Cafe Member
Joined
Jan 18, 2012
Messages
381
Location
TN
I mostly use the milled ring blanks from hoover and strong. keep a few different widths and thicknesses on hand, and stretch or compress them to the finger size needed for whatever is ordered (within close sizing)
don't have to worry about measuring out lengths and converting to ring sizes, or solder seams.
at least for simple engraved bands which is most of the custom ring requests I get.
 

Roger B

Elite Cafe Member
Joined
Mar 17, 2008
Messages
350
Location
Adelaide, South Australia
For those in Oz and the UK - rough estimates will be size P = 6omm. Plus or minus 1.2mm for each size more or less. This has worked well for me for 4mm wide bands.

Roger
 

LVVP

~ Elite 1000 Member ~
Joined
Dec 13, 2006
Messages
1,382
Location
Toronto
It was helpful, thank you very much for the info.

By the way, your website is very friendly and looks very nice.
 

Chujybear

~ Elite 1000 Member ~
Joined
Nov 3, 2011
Messages
1,079
Location
Haida Gwaii
My website?

Calculators not mine if that's what you mean?
But since you mention it.. I did just update my website. Lol
 

Chujybear

~ Elite 1000 Member ~
Joined
Nov 3, 2011
Messages
1,079
Location
Haida Gwaii
So an update on that ring calculator. And the other formulas here.
I did the one the calculator had me a couple mm off the formulas I got here. I figured I would split the difference. Long story short (and it is a long story involving me having to leave the rings with a stranger inside security at the airport), the ring was fully a size to big.
Willing to accept the possibility of operator error. If not. I don't know.
 

Hora

Elite Cafe Member
Joined
Dec 28, 2008
Messages
237
Location
Saudi Arabia
Ring sizing depends on what I am about to do. As a engraver / jeweller I calculate to the job. There are a few possibilities that I work with:

  1. I want to make a ring from plate, bend it and solder it to a ring shape. Here I have to take the thickness of the plate into account with my calculation for the ring size. Needed material is therefor: ring size (actual size of the finger) + 0.5 x Thickness of the plate x Pi (3.14).
    Then it comes to skills like how well I bent the plate into a ring making the seam to weld easy. If I need to work the seam I still have to add some grace length here as well.
  2. I want to work the outside of a ring and need to know to exact outside area / length.
    Here I can take the total diameter of the ring x Pi. This will give the exact length of the outside surface.
  3. I want to resize the ring by cutting a piece out.
    This is actually pretty easy. Every mm of a ring finger size is 1 x Pi in mm. If I want the ring to be 2 mm small or larger: 2 mm x Pi = 6.28 mm to be added or removed. ( I think that mm work in this case faster than inches)
My conclusion is that one formula for ring sizing is a bid thin for me.
I hope that the explanation of my way of working will help.
 

Chujybear

~ Elite 1000 Member ~
Joined
Nov 3, 2011
Messages
1,079
Location
Haida Gwaii
Thanks Hora.
I will try it next time.
This ring I carved the inside before bending. Wound up a full size off, but that was the least of my problems.
I had to get these rings to a wedding that was happening in four days. Courrier said it would take at least seven days to get there (remote area). I was flying out the next day to a different, but also remote area. I knew a guy flying to the wedding, but my connection left the airport hours before his even arrived.
I figured my best bet was to leave it with the information desk. But they wouldn't take it. Lost and found would pull it out of security. Air canada wouldn't hold it.
My saviour. Sunglass Hut. I took a leap of faith in the nice girl there. And, long story short, the wedding wasn't ruined.
 

Latest posts

Sponsors

Top