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Curved Problems

With our changeover of basic range just around the corner we thought we should highlight how much effort and investment goes into producing the high quality body jewellery we stock. It may come as a surprise but the humble curved barbell and circular barbell throw up the biggest problems for jewellery makers. This blog will show some of the solutions to these problems by jewellery design and the processes and machinery used in curved jewellery production.

Disclaimer: These are not the only methods to produce these items. There are many ways to make everything.

Shape

Circles aren't as simple as they seem. Who doesn't love a bit of radial geometry!
Circles aren’t as simple as they seem. Who doesn’t love a bit of radial geometry!

Body jewellery may look like simple pieces of metal but the exact shapes have been refined over decades to create designs that promote a smooth, healthy heal and lifetime. Sadly not all body jewellery is made equal and a lot of the time lower quality pieces come from aiming to create the cheapest item possible rather than creating the best.

Geometry seems simple on paper but making a finished piece of jewellery from a drawing is made much more difficult due to implant grade Titanium being notoriously difficult to work with.

Curves or Bends?

The key word in curved barbell is “curved”. High quality curves are made to be an arc from end to end. Having the same profile and curve the entire length of a wearable is required so jewellery can move through a piercing without stretching and irritating the piercing channel (as shown in fig 1 and fig 2 below). Lower quality curves are bent in the middle which will put more pressure on the centre of the piercing channel as well as stretch the piercing channel as it passes through (as shown in fig 3 and fig 4 below).

Bends

A “bent” barbell is just that; A barbell which has been bent. The bend can be applied manually or by using machinery such as a hydraulic press. In both methods the barbell is held in a vice or jig (fig 5), a lever is placed over the barbell and then force is applied (fig 6). Ideally some form of go no-go gauge for manual or a pressure gauge for hydraulic would be used to create standardised bend. These methods are fast and low cost but require lots of operator time and there is a high chance of variations in the final pieces.

Curves

As a curved barbell is a full arc and it is generally made from a coil, full ring, part ring or straight bar blank. Whichever blank (a piece of material prepared to be made into something (such as a key) by a further operation) is chosen there is going to be material wastage. This material waste goes onto the final price of the piece so it is already going to cost more than the bent barbell. Coils create the most wastage but can also increase the speed (And therefor cost) of the cutting, drilling and threading stages. Full rings are less expensive in material costs but are more manually intense due to not being able to create batches. Part rings are generally made from coils and full rings or machines such as CNC wire benders can be used. CNC wire benders are very specialised and very expensive pieces of machinery. Curves minimise the material wastage but due to the high cost of CNC wire benders and a specialist skilled operator being required they increase the setup cost significantly. Bar blanks will be pressed into a custom jig to form them in a hydraulic press.

A CNC wire bender in action

A part ring would now be ready for drilling and threading. Coils and full rings will need to be cut down to the correct length first and this will require using specialist jigs to hold them and either a power saw/grinder or a milling machine. If a milling machine is used then it can also be used for the threading section too. All of these machines add cost. A saw/grinder setup would be the cheapest setup cost but has an ongoing cost due to the manual nature of this method. A milling machine would add a large setup cost but has a much lower ongoing manual cost as batches can be setup so the milling machine can keep running on its own.

No two body jewellery companies make their curved barbells to the same radius. As piercers this variation can be useful as no two bodies are the same but does mean stocking multiple brands.

Circulars or Horseshoes?

Just like curves, the keyword in circular barbell is circular A circular barbell will move through the piercing channel smoothly and with minimal resistance (fig 7 and fig 8). A common slang name for circular barbells is horseshoes, but a horseshoe shape isn’t ideal for body jewellery. Horseshoes cause similar issues to bent barbells as they also distort and stretch the piercing channel during movement (fig 9 and fig 10). This distortion can lead to irritated piercings. The extended legs on a horseshoe also bring the attachments closer together which gives a different aesthetic and increases installation difficulty.

Horsehoes

A horseshoe is basically an arc with extended legs on each end. The legs are a symptom of the production method and process order. A horseshoe will be drilled and threaded before it is formed. The forming can be completed in a manner of ways but the most common would be to use a custom jig and a hydraulic press. A barbell would be placed into the jig (fig 11) and then the press would apply force to wrap the bar into a U shape (fig 12). A second stage jig and/or press would be needed to push the legs in towards each other (fig 13). The initial setup cost for this method would be much less but the ongoing manual cost would be high.

Circulars

Hydraulic press 10 ton
A hydraulic press with pressure gauge.

A circular barbell would use some of the same machinery and blank shapes (albeit in a different diameter) as curved barbells. Coils and Full Rings would follow the same process as curves and Part Rings could also be produced using the CNC wire bender or by using a hydraulic press and custom jig.

Threading

Threading creates the biggest problem for high end curved and circular barbells. This is because the threading must be added after the shape has been formed otherwise the thread will be distorted and will not work (fig 14). All of the lower quality curves and circulars can have the threading added first as they have straight sections on the end that doesn’t distort during forming (fig 15). The straight end section uses faster processes, less steps and lower skilled operators so is much cheaper.

Adding a thread inside a small curved item adds an extra level of accuracy. Drilling a straight thread inside a curve doesn’t leave much space for error and can cause a weak point in the jewellery (fig 16). The accuracy required to avoid this can be achieved using machinery and skilled operators but this significantly increases the cost.

Some of the machinery that can be used to thread our circular and curved barbells is cutting edge technology. CNC 5 axis milling machines can be used to batch produce items using specialised jigs, CNC lathes can be used for single item manufacture but both of these methods are high manual intensity for highly specialised skill sets. Cutting edge technology comes at a cost though.

We love the amount of effort and perfectionism that goes into the body jewellery that we sell. Having suppliers that care as much about the jewellery that goes in your body as we do at Rogue really makes us happy. The items we use at Rogue are made to last a lifetime without harming your body, all while looking amazing. We hope that this blog has helped you see that simple looking items can be anything but simple to produce.

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