Question: How do you layout on pave eternity ring

[ede]

Greetings Cafe members! First off, as my first "official" post, I want to thank everyone for making this site such an an inspiring place to learn and share. It is truly an honor to be in the company of such talented and creative artists across the globe. I hope some day to "give back" to this community in some way.

On to my question:
I am making a practice eternity pave ring and am wondering what methods different stonesetters/engravers use for layout of a ring.

Specifically, my ring is 18.3mm in diameter and stones are 2mm in diameter. I'm allowing .2mm between stones.

So far I've calculated 18.3mm x pi ÷ 2.2 = approximately 26 stones. 360° ÷ 26 stones = approximately 13.8°. So I need to layout stones every 13.8°.

How would one go about laying out 13.8 degrees consistently on a ring? I understand the traditional method is putting some wax on the ring surface with the stones table down and then marking where culet of the stone would be. Although I could do this, I'm looking for an alternative method.

Additionally, I've seen the ring genie, which looks like a beautiful piece of equipment, but at this point am looking for another (read cheaper) method. I've heard of people using lathes to do this with but have no idea how one would go about it.

Any thoughts or suggestions are appreciated.

 

[Gemsetterchris]

Haven't a clue
But you need to figure out the diameter from where the girdles will be sitting at, not the total width.
I'd forget the degrees & figure it out with dividers.

 

[maplesm]

Take a look here for another idea http://www.ganoksin.com/benchtube/video/961/Preparing-to-drill-holes

 

[GTJC460]

I usually layout in a cad program to figure the spacing/adjustment of my dividers. Then print the 2d line drawing to life size. After which I set my dividers using the markings on the paper printout.

 

[Eric Olson]

Divide the ring into quarters or 6ths and put the same number of stones in each section. .

 

[RDP]

Somebody posted this link before it may be helpful to you,

http://www.cgtk.co.uk/metalwork/reference/divider

Richard.

 

[JakeW]

I have done it several ways.
1. Take piece of paper wrap it around the ring until it goes all the way around then mark the paper then unwrap and measure how long it is. That should be your circumference. Then divide by size of stones to figure out how many stones you will need. This is not perfect because the girdle is below your surface of the ring so it does change your circumference also the amoumt of gap you want. Then go around with dividers to make sure it all equally fits. This method works also if you want to equally space 10 stones around a ring. I also have a ring manderel that has 32 equally measured lines that run down the length. That makes it easy. But the best way is to lay it out in CAD. I have also looked in a Hoover and Strong catalog that tells you how many stones in a particular size that go around an eternity band. Hope this helps

 

[oiseau metal arts]

CAD sounds like a lot of work to do something simple.
.... take diameter of the stones you are using, and add 0.2-0.3mm that should give you the center to center spacing.
I took a setting class with Blain Lewis, and he showed using the thickness of a business card spacing between each upside down stone. so... cards measuring somewhere from 0.2-0.35mm thick... just add that in the measurement. this gap between stones during layout compensates for the stones being closer together once set down inside the ring, and will end up set girdle to girdle when finished. if you want extra space between each stone then add a couple 0.xx mm to allow for the spacing you want.

unless you are using a machine to measure out and drill at exact angles then trying to calculate the degrees spacing off of the center of the ring isn't necessary.

doing multiple rows.... mark and drill the center row then measure and mark off the rows to either side. drill.... repeat. (and with 5 rows, 2/3 coverage using .9mm- 1.1mm stones there is A LOT of repeat)

outside of paying someone else to do it, this is the simplest way for me.

anyone know simpler....id sure like to know it too.

 

[Gemsetterchris]

It's quite an effort to get a perfectly accurate layout all the way around, stones are generally not "exactly" the same.
Try & be as near as you can with your mathematics, but you can fudge a small discrepancy with the last couple of stones without it being obvious.

That may sound abit amateurish, but personally I find a little bit of eyeballing works better than trying to too mechanical.

 

[dhall]

Welcome to the Café,

I initially came up with a spacing of 2.3 mm. Gemsetter Chris (who sets stones for a living) brings out the first point about basing your calculations on the depth of the girdle, not the O.D. of the ring. In rough terms the crown height of a 2 mm stone will be around .3 mm. Using your math, with a 17.7 mm root diameter (girdle depth), I came up with 25 stones. Dividing the circumference of your O.D. (18.3 mm) by 25 gave me 2.3 mm. I think if you tried to squeeze 26 stones in this ring, you'd sadly find out the importance of figuring out the girdle depth first.

There is a slight flaw with the 2.3 mm spacing, though, as it is the length of the circumference divided by 25. When you use dividers, you would actually be marking off the chord of an arc, not the arc itself, since the points of the divider ignore the length of the arc. In truth, the dividers should be a whisker less than 2.3 mm. An actual divider spacing of 2.294 mm would precisely step off an arc length of 2.3 mm on an 18.3 mm diameter ring, i.e. 2.294 mm is the chord of a 2.3 mm arc length of an 18.3 mm diameter circle. Figuring out how to set dividers .006 mm less than 2.3 mm is probably the hardest part of this whole exercise. Oiseau's tip about a business card being .2 - .3 mm is a great idea. The thickness of an average sheet of copy/printer paper is .1 mm, just to show how small .006 mm is in relation to an easily grasped jig (a piece of paper!).

If you're familiar/comfortable with CAD, it'll give you the answer in a just a few moments, probably about the same time it'd take you to figure out the geometry/math with a calculator, if CAD isn't your go-to tool. Whatever is comfortable and gives you the correct answer is the right tool. Jake's tip about wrapping paper around the ring is great because it automatically compensates for varying thickness, and can it can lead to a very simple and elegant way to divide a length into equally-spaced segments, without the use of a calculator or doing any math! You'd draw another line, starting at one end of the circumference length, at a slight angle away from the length, i.e. a "V", and the second leg may be as long as needed to satisfy the next instruction. Step off the desired number of segments on this second line, using equally spaced segments. The actual measurement of the segments doesn't matter, they just must be equal in length. At the end of the last segment on the second line, draw a line to the end of the circumference length. Draw lines parallel to this line from each of the stepped-off segments on the second line, and you will have divided the circumference line equally into the desired number of segments. Wrap the paper around the ring again, and center-punch the marks. Thank Euclid for this one.

Best regards,
Doug

 

[Gemsetterchris]

That`s enough to put you off bothering

Just to add, you`ll probably find your 2mm stones vary from 1.96-2.04mm, then after all the faffing about with marking out..you need to be accurate drilling/opening holes without moving off center.
The other thing is..everyone is presuming that you`ll figure the depth so the tables are flush..personally i`d say that`s too deep for 2mm stones.


best of luck

 

[Keirkof]

You heard most of the important things in the previous posts, maybe let me add my own 2 cents worth...

- Inspect your stones visually before you start. Eliminate any damaged ones, also any that are too included or too dark or white to get satisfactory results.

- Invest in a stone sieve. There are 6 cm diameter ones from € 150 (less than $ 200). I started working with one of these from an indian company called 'Moon' that I bought in Antwerp. It had one plate that was off size, but I worked around its shortcomings without too much trouble before buying myself a better one (at double the price). That way, you'll know in advance how much the stones vary in size and can adjust your calculations and measurements accordingly.

- I also 'do the math' for a ring to get an idea how many stones fit under ideal circumstances. No matter how you measure, you should never end up with a plan for more stones than you calculate based on the outer circumference. Consider it a failsafe.

- As for the distance between the stones, I usually 'eyeball' them. I stick 4-5 stones table down on the ring using beeswax, checking the spacing visually under the scope. Then I hold my dividers next to each stone to set the distance on the dividers. After that, draw a center line and punch one reference point to start from. Then walk your dividers all around the ring (don't push down hard at this stage, you're only testing) and see where you end up. Enjoy the warm fuzzy feeling when you arrive at exactly the number you calculated or one less than that. If you have more stones than you calculated, start again from the top and check what went wrong.

- An important skill in order to 'nudge' the holes so you arrive exactly back to your reference punch position, is to know how to 'squeeze' the dividers open or shut in order to slightly widen or tighten the gap. Widening is safe, tightening is something you only should do if you're sure you had plenty of gap to begin with. Use your thumb and index finger to hold the little bar on top of the dividers, with one leg of the divider down in the metal. Gently 'pull' your index finger while providing counter pressure with your thumb to widen the dividers ever so slightly before putting down the other leg. To squeeze the dividers tight, push with your thumb and 'pull' with your index. You'll soon learn to use this trick either to adjust the spacing slightly for every hole, or you can adjust one in every three etc. Once you have your 'lightly scribed dots' on the whole circumference right, make one last pass pushing them down clearly so you will drill at the right spots.

- Start slow and deliberate, practice will bring speed later on.

- Enjoy!

 

[Jan Hendrik]

I like to use the KISS method (keep it simple stupid). Mark a centre line with dividers from the edge of the ring. Then set your dividers on the stone diameter plus o,1 to 0,2mm. Start marking out and with luck your marks will work out perfectly. If it does not, then simply make a micro adjustment on your dividers and re-mark with slightly longer marks to differentiate between the first set of marks and the new ones. This is the method I have been using for years. Complex mathematics almost always turns out to be more work and the results are usually not satisfactory.

 

[ede]

Wow, what an outpouring of advice I've received in just 24 hours--Thank-you! I will have to re-read everyone's posts to digest everything. Lots of great techniques/methods were presented and it just goes to show that there are many roads that lead to the pavéd streets of Rome!

 

[Gemsetterchris]

If you already have stones you want to use, pick out 2 or 3 of the biggest diameter & use those for the measuring.
Another way would be to do your girdle depth diameter x pi divided by number of stones to find the diameter you need.

The credit card trick is a good idea for spacing on some sizes, but not for that micro stuff..which incidentally I hate on rings (as fancy as they look they are asking for trouble)...save it for pendants & earrings or whatever.

Your going to learn a lot from this project.

 

[GTJC460]

Using my method, I can figure out the layout in less than 90 seconds. But I also have my computer on all the time, have the software, and have at least 10000+ hours of using the program. So you could say that it's become second nature to use the same as a calculator.

 

[Marrinan]

Please read the section of proportional dividers - dividing a circle into equal parts. You will find this in the tips section or do a search for proportional dividers. No eyeballing is allowed in skilled trades. As my old English cabinetmaker master told me "it's bloody flippin butchery plain butchery-do the damn thing again like a tradesmen worth his meat and salt" Use the tools you were taught to use and use them right"- George Poole-Master Joiner