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It’s a Stretch

Expanding your skills to achieve a perfect fit

By Lee Krombholz 

Sometimes in business, the fates align.

A few months ago, I noticed an uptick in interest in “stretchy” jewelry—pieces made with springs that allow them to stretch but then retract to their original shapes—and I was thinking about trying to make something in this style. Around the same time, one of my good clients happened to stop in and express her frustration over not being able to wear the custom engagement ring I had made for her 15 years prior. She had developed arthritis in her hand, and when she was no longer able to fit the ring over her knuckle, she stopped wearing it.

She wasn’t interested in changing the look of her ring, which featured a wide tapered band. While I could have used the existing ring and created a custom adjustable shank for her to get around the three-size difference between her knuckle and her actual finger size, the stretchy jewelry trend got me thinking in a different direction.

Stretchy bracelets and rings offer some advantages over traditional jewelry, including bypassing knuckles and hands for a better fit. Also, the comfort of these non-rigid items makes them very soft and comfortable to wear. And although originally these stretch styles started out being construct-ed with elastic as the stretch component, they have since developed into more sophisticated fine jewelry. Stretchy jewelry no longer needs to look stretchy.

I suggested the idea to my client, showing her a beautiful spring-loaded stretchy diamond bracelet that we’ve carried for a couple of seasons. A longtime client who has trust in me, she was game even though it would mean compromising on the design of the ring. Her original ring was two-tone with white and yellow gold. Given the complexity of making all of the parts and the precision that would be needed, we decided to make the entire ring in 14k yellow gold.

Once we settled on the final design of the ring, it was time to start the experiment.

Material Sourcing

While CAD design makes stretchy jewelry very feasible, there are challenges to making a piece like this. The first of which was finding long sections of stainless steel spring with just the right amount of tension.

Luckily, we live in the age of Google. A quick search for springs provided me with a handful of custom spring manufacturers. However, these “spring people” needed specifics on what I wanted made, and saying that I want springs so that I can make stretchy jewelry is not all that helpful. Fortunately for me, I was able to use the research of another jeweler as my starting point. I carefully stretched open the stretchy diamond bracelet I had used as an example for my client and was able to measure the wire thickness and overall diameter of the spring inside. Although this wire was being used in a bracelet versus a ring, I took an educated guess that my piece would need the same size wire.

The next step in my pursuit began with a conversation with John Newman of Southern Stamping and Spring (south ernspring.com). I knew that I needed a stainless-steel spring to avoid rusting and discoloration. The bracelet I was using as a sample had a spring with an outside diameter of approximately 0.05 inch and a wire size of about 0.01 inch. But then another question was posed: How many coils per inch? Based on the short section of the bracelet’s spring that I could expose, I estimated this at 72 revolutions per inch. With this, we were finally off to the races!

In working with a custom spring manufacturer, the minimum order left me with 60 feet of stainless-steel springs—enough to make stretchy jewelry for a lifetime. Or so I thought. By the end of this project, I wound up using almost 10 feet of the material because of the multiple experiments conducted.

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Pulling It All Together

Once I had my supply of springs, into CAD I went.

Using the client’s finger size, the spring’s outside diameter, the layout of the diamonds, and a maximum height of the design off of the finger, I created a basic design for the ring. CAD helped me to create a sectioned design that allowed for the diamonds’ depths and clearance for the two springs. I also included a dedicated space in the underside of the ring that would fit the springs perfectly. I printed a wax model of the design in one piece to show my client.

She liked the concept, and once she signed off on it, I started on the next phase of making the ring, which wound up being filled with its own unique series of learning curves.

Making the sectioned design and sprued parts ready for casting was not hard in CAD. It also was vital in getting these sections to have the right-side angles that allowed them to fit together perfectly and that, when combined, would make the right finger size.

After printing and casting the segments, I secured the still-sprued parts on shellac plates and set the client’s diamonds from her original ring. I like keeping small parts sprued as long as I can to make the pieces easier and more solid to set and finish since the sprue helps stabilize the pieces and offers me something more to hold onto when polishing. After completing these steps, I sawed the pieces apart and finished them to just shy of a final polish.

It quickly became obvious to me that some of the biggest challenges were in store with the final assembly stage. It was difficult to hold the spring in a slightly sprung state and complete the final connection. Here is the process that I developed after hours of frustration.

I determined that I needed to feed an internal wire into the ends of the springs to make the connections strong. Using a small diameter low-volt beam on my laser welder to avoid affecting the temper of the spring, I welded one end of each of the two springs to a 3 mm long piece of white gold wire. (I chose white gold so that the wire would better blend in with the spring.) Getting these laser settings right to avoid melting the thin spring wire while getting a good weld took some practice.

Next, I welded these wire-filled ends of the springs to the inside of the ring. This created a solid bond that allowed me to pull the other end of the springs against it in order to achieve the right level of tension. After stringing the segments of the ring onto the springs, I was ready to make the final connection.

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I knew that I needed to have the completed ring under a slight amount of tension, and how to make this connection took some thought. During the testing process, I tried the ring on my finger to get the feeling of it. The connection I created was my best guess for the right amount of tension, but it would need to be field-tested to know for sure.

To cut the spring and keep it in a sprung condition while I made the final connection, I used a small piece of solder to hold it in place. Already having worked out the correct laser setting, I was able to weld the remaining ends of the springs to the white gold wires quickly and securely.

Because this was my first attempt at a piece of stretchy jewelry, I performed a series of tests to make sure it would hold up to daily wear before delivering the ring to my client. During this process, I stretched (and even over-stretched) the ring to make sure my connection held and the tension was right. I ended up taking the ring apart and reconnecting it a few times before I was happy with this. At times, it was difficult to get the same amount of tension in both springs in the ring. Other times, there might be some gapping in the spring. It was also possible to have too much tension on the spring, which would begin to stretch out as it lost much of its tension. After much trial and error, a perfect final fit was achieved.

Because I had started working on this project during the holiday season, it wound up taking me about six months to complete. When I finally presented the ring to my client, she was very pleased with the design. She wears the ring daily with enthusiastic satisfaction. She even takes it off a number of times a day to show her friends how it works. And when I had a chance to clean and inspect it a few days ago, it appeared to be holding up perfectly.

This was a great learning experience, and I would not hesitate to take on another such stretch project. However, if I were to attempt another similar type of ring in the future, I would build in internal caps to cover the interior ring segments, making the springs less visible and the inside of the ring more attractive.

I hope this article encourages other jewelry designers to create jewelry using this concept. The benefits of this springy approach are plentiful, and while the learning curve is somewhat steep, having this article as a head start will hopefully make this process go a lot quicker for you.

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