Case Construction

At Draken, we have always prided ourselves in creating unique, original designs, but first and foremost our watches need to be functional. Easy-to-use bezels, highly legible dials and handsets, and reliable work-horse movements mean that Draken watches will not just be fit for purpose, but excel in outdoor environments.

Our case design has become a signature for the brand, starting with our first watch – the Tugela. Taking inspiration from the Protea flower commonly found on the slopes of the Drakensberg mountains, the case has a tapered shape, meaning that the bottom of the watch is smaller than the top, which flares out at the bezel. This naturally makes the bezel more accessible, allowing for improved grip when being rotated.

Case construction is critically important when it comes to tool watches. Dress watches, and the brands that design them, can get away with designing a sleek, thin case. The intention, after all, is that they should be worn with a suit, or while out sipping coffee on the weekend.

Nothing wrong with that of course, but those watches with wide tolerances and push-in crowns won’t cut the mustard on a 10-day endurance hunt, or a 30m wreck dive. So here are some considerations when it comes to tool watch construction.

The case of the Tugela takes inspiration from the Protea flower

Water resistance

There are two important factors that determine the water resistance of a watch when compared to a cheaper fashion watch. Those are:

  1. A well-sealed case
  2. A sufficiently thick case

The first may seem obvious, but the reality is that not all seals are created equal. What you want to look for (at a minimum) is a screw-down case back, and screw-down crown. On both those seals, there should be at least one decent-sized O-ring gasket. Many watches have gaskets, but the seal doesn’t provide enough tension on the gasket to make it thoroughly watertight.

Next, the case needs to be thick enough that it can withstand the pressure at 100m, 300m, 500m or more. Generally the greater the depth rating, the thicker the case needs to be. This includes the case back, the crystal, and the side walls of the case.

For most daily situations, 100m water resistance will be more than enough. The screw-down case back and crown will ensure moisture during wear and the odd swim, will not enter the case. We’ll talk a bit more about water resistance in a future email.

Chrono pushers

The pusher buttons on chronographs are a common area for water resistance failure for that genre of watch. Often, tool watch companies will add screw seals to these pushers. However, this limits the usability of the watch, forcing the wearer to first unscrew the two pushers before they can use the chronograph function.

In some cases, you would have to remove the watch to unscrew the pushers. To eliminate this issue, we used a triple gasket system, allowing the pushers to still function, even while underwater.

The technical detail of the chrono pushers of the Kruger

 

Rotating bezels

A rotating bezel allows the wearer to perform a number of tasks, be it recording a dive time, tracking a second/third time zone, or as a countdown (egg-timer style) function. When it comes to tool watches, there are numerous ways of implementing the rotating bezel. Some of the implementations we have explored include:

  1. Uni-directional diver bezel (clicking wire and ratchet spring plate)
  2. Bi-directional internal rotating bezel
  3. Bi-directional GMT bezel (detent mechanism)

The most affordable process to implement a diver bezel is by clicking wire. It is essentially a spring wire that bends around the outer side of the mid-case and curves upwards towards the teeth of the bezel, thereby creating the clicking action. The problem with this method is that it tends to allow a considerable amount of back-play, and it doesn’t apply tension to the inside of the bezel uniformly. A ratcheting spring plate is our preferred implementation (Tugela and Kruger), with three curved springs creating tension with the teeth of the ratchet equally. This also ensures minimal back-play and a satisfying and tactile ‘click’ upon rotating.

The locking spring (left) keeps the bezel in place, and the ratcheting spring plate, with its three springs which enables the bezel to turn in one direction.

Internal rotating bezels rely on a gear attached to a crown that rotates the bezel ring. The bezel can be rotated in both directions, as the crown is rotated. They are difficult to get right as the friction of the bezel ring is often dependent on minute tolerances between the dial, movement holder, upper case and /or mid-case.

For the Tugela GMT we implemented a bi-directional detent-style mechanism using a pin, allowing the bezel to rotate 48 clicks in both directions. While this method does add slightly more friction versus a ball bearing, it is more affordable and easier to assemble.

Faraday Cage

Magnetism does present a major problem to mechanical watches. The hairsprings and balance wheels on these movements are highly susceptible to interfering magnetic fields from everyday items like speakers, cell phones, handbag clasps, and electric razors. Even the accuracy of some quartz watches can be affected by magnetism.

To help disperse these fields, some watches utilise a Faraday Cage – a soft iron cage that sits around the movement. We used this construction on the Aoraki to further protect its movement from magnetism, taking the default anti-magnetism of the movement from 4800 A/m to 20,000 A/m.

The Faraday Cage of the Aoraki

Drilled lugs

If you have ever tried to change out a watch’s bracelet for a strap, you’ll understand how impossibly frustrating it can be, especially on a high-quality watch built to tight tolerances. Get the strap changing tool at the wrong spot even by the slightest bit, and you are likely to put a scratch or two on the inner lugs. Say goodbye to that box-fresh polish.

To solve this problem, many watches have lug holes that are drilled all the way through. This enables you to push the spring bars in with a hairpin or similar tool and remove the bracelet or strap. The Aoraki was our first model with drilled lugs.

Another way to make strap changing easier is with the use of quick-release pins. These straps and bracelets have little levers that you push inwards, eliminating the need for tools altogether. We typically employ quick-release spring bars when the case design won’t accommodate drilled lugs.

Crown guards

Our Tugela models feature robust crown guards that take the bevelled edge theme a bit further. The crown guards protect the crown from a glancing impact, similar to some pauldrons seen in mediaeval shoulder armour. They will not protect the crown from a direct impact, however. Having an offset crown can lessen the likelihood and extremity of a direct impact. On our Benguela and Aoraki watches the crown is positioned at/near the 4h position. This also makes the watch more comfortable, reducing that digging into the back of your hand.

The crown guards of the Tugela GMT

With each new model, we are improving and refining our case construction. In the next email we’ll discuss water resistance in a bit more depth, pun not intended 😉

Kia kaha.

Mike

4 comments

  1. Really appreciate this information particularly for those of us new to this world. It really helps differentiate man’s understand why some brands, while less expensive, may not be the best choice from a quality standpoint.

    1. Cheers Clark. Appreciate the feedback.

      1. Hola vivo en España y no sé cómo puedo comprar un draken tugela . Por dónde puedo comprarlo sin tener problemas ?

        1. Hola pedro. Hay dos opciones: watchbandit.com con sede en Alemania o welovemicrobrands.com con sede en Polonia.

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