The Wedding Band Size Story. Does Mandrel Size Matter ?

Nugget
Jun 2, 2021
4 min read

There probably isn’t one thing more confusing and less consistent than the way we figure out a person’s ring size. That problem seems to multiply when we are sizing a person for a wedding band. In a lot of cases, the consumer is unfamiliar with what a wedding band should feel like on their finger. In fact, depending on the person, there may be a measurable difference between a comfortable and a secure fit. Then, we have customers with larger knuckles and some of the inside profiles slide over their knuckle but end up uncomfortably loose once they reach their destination.

It wasn’t always this way. So where and when did this problem begin and what is to blame? Historically, we have to roll back time to the 70’s when the bar for wedding band sales was set very low. The many band manufacturers battled for the business by lowering their prices so much that is wasn’t unusual to lose money when they sold the product. Retailers, demanding transparency, somehow got the manufacturers to sell their goods at a fixed price over metal. This meant that the lighter the band, the less money was made and it was more likely that the product was unprofitable.

Enter the very first Comfort Fit wedding band. The premise was that the band, with some type of contour on the inside profile would be more comfortable. Comfort fit bands needed to be made thicker than regular bands or the edge of the ring is very thin, sharp, and uncomfortable. Thicker was heavier and more product became profitable again. It would have been nice if manufacturers didn’t decide to sell products at a loss in the first place. Once they did, it was impossible to turn the misstep around.

Then somebody realized that for a lot of folks, the comfort fit ring wasn’t that comfortable. Sure they slide right over your knuckle without a good soap-up, but once they were on, well a lot of us don’t like wobbly rings that constantly shift and angle. Enter the comfort fit two, which does make sense, in effect, cutting off the edge metal but leaving a much longer landing pad to sit straight on the finger. This type of comfort fit is further softened during the manual polishing when the inside edge (where the bevel meets the inside of the band) is lightly broken.

So how does this impact getting a person’s ring size correct? Technically, ring size is determined by measuring the I.D. (inside diameter) of the product. In image one, we size a cross-section of a 6mm comfort fit band. In this case, the comfort fit is the second type I described with a longer landing pad.

Figure 1-Inside diameter (I.D.) of a ring. In this case, a perfect size 9 is .745 thousands of an inch (or just about ¾ of an inch). The measurement for size is taken at the narrowest point.

What kind of Mandrel are you?

All the rings demonstrated in Figure 2 are the same size but they also represent the three different ways that the inside of a band may be shaped. While this works in a machine shop, it doesn’t translate well to the retail counter. When you place these three different products on a mandrel, you can see why.

Theoretically, because the narrowest I.D. measurement on all these bands is the same, they should fit the same, but they do not. That depends on what a person perceives to be comfortable.

So now you’re probably thinking, “No wonder I have such a hard time getting the correct size products from my suppliers on a consistent basis.” It won’t make you feel better when you find out it gets even worse…

Because we run a machine shop within our facility, we measured our mandrels and found that they were inaccurate and inconsistent. We purchased 10 mandrels from the same exact company and asked them to do what they needed to do too get us the best, highest end mandrels that they could find. We needed almost exact measurements. When we received and compared them, using the most sophisticated measuring instruments, look at the variances we found:

Figure 3: In our 10 mandrel comparison our results were all over the place. In the small chart to the right you can see the range of variance when compared to the actual standard (technical measurement).

It shouldn’t surprise you to know that the various sets of ring sizes on the market are even more inconsistent than the mandrels. Wedding band and jewelry supply companies supply these under the guise of solving a problem when they are just adding layers of complication. We don’t need more bad and inconsistent attempts at locating a moving target.

In most industries, someone in engineering solves the problem and the industry embraces it. Something that is fair, easily adaptable with as limited expense as possible. Fat chance that this can ever happen in the jewelry industry.

So the next time you hear someone use the phrase comfort fit remember that it was only comfortable until the idea gained weight.