MK2 Dial - Part 3

As we discussed in the last installments, the MK2 dial is a complex assembly of small individual elements. All made one by one, finished one by one and assembled and fixed one by one. In this installment of the "behind the scenes" we will show you the process of how the dial elements are made and finished, and how the base dial is anodised to our "topaz blue". First: the end result:

The hour markers, or as we call them "batons" as well as all three hands are faceted. The facet is at 4 degrees, a very small angle, but the effect is massive. In person, the facets on the dial and hands not only dance in the light, but also give a strong visual line down the centre of the hand. The keen eyed of you will have noticed another interesting feature- the 2nd "grain" angle within the facet. We call this technique feathering. The grinding finish that we apply on the hands is angled at 45 degrees to mimic the shape of a feather. The inspiration comes from the coastal birds you see on the Sydney's Northern beaches- seagulls, sea eagles, even sulfur crested cockatoos and lorikeets! There is a massive technical challenge in making this decorative pattern. If the facets are off centre by more than 10 microns or so, your eye begins to pick up the lack of symmetry, so it becomes very important that all the jigs, and raw hand dimensions are checked and kept to a tight tolerance Secondly, the angle of the "feathering" creates a complex compound angle that we have to hold the part on, which calls for a very complex jig-making exercise. But without getting ahead of ourselves, we still have to make all the other parts! The numerals, batons, and hands all start in the same way. Raw material of 0.8mm titanium is glued down to a special pallet. The material itself has been stress relieved and flattened in prior operations. Here you can see the progression of the batons and numerals being milled out. The hands are done in a very similar way.  A special high strength glue is used to hold the parts to the pallet, allowing us to profile the outside and inside shapes. The tools we use to cut these parts are so small that the tip of the tool can get lost in the space between the lines of your finger print! A drop of oil on the 0.2mm drill. The batons and the numerals are not simple 2D shapes, they actually have two little "feet" on the backside. These feet fit inside the holes we drill on the base dial. The diameter of the foot is 0.19mm with a tolerance band for the diameter of +0 microns , -10 microns. The thickness of the batons and numerals is also important, If they are too thin they will distort and twist when assembled on the base dial. Quality control - Measuring the thickness of the numeral and baton. Measuring the diameter of the baton pin. Measuring the thickness of the parts we make is quite tricky. The probe tip we use had to be custom made for us in Germany! Standard probe tips available as off the shelf items are too large and would not allow us to get to the small areas between the pins of the numerals and batons. This custom probe tip is one of the many thousands of dollars of custom equipment we had to either make ourselves, or in this case commission from gauge making specialists. After all this care, time, attention and patience we are left with our raw, ready to be finished parts! The next step is feathering. There are a couple of challenges in this process. The first one is how to hold such a small part. This leads to a complex exercise in jig-making. The jigs used to hold our parts take weeks to design and make. They go through many iterations to land on the right approach.  The feathering is done on a machine called a surface grinder. Surface grinding is an extremely accurate method of removing small amounts of material in a very controlled way. It takes years of expertise to master this machine by tradespeople called "toolmakers". James, our in-house toolmaker is an expert and only after nearly 20 years of experience, is he comfortable with this type of work. The type of abrasive wheel used is a critical part of achieving the right finish. In fact we tried numerous different combinations of wheel and coolant to arrive at our own "titanium feathering recipe". Dial Anodising The base dial is now cleaned and prepared for anodising. Funnily enough your fingertips are some of the best cleaning implements available! The textured surface of your fingers allows for dirt to be trapped and taken away from the surfaces you clean. In combination with soap and detergents we manually clean each base dial. It's imperative that the dials are free from any residual oils, so 99.9% Isopropyl alcohol bath in an ultrasonic cleaner is the final cleaning step. Titanium anodisation is an extremely complex electrochemical process, but in essence a Titanium dioxide (Titania, which is a ceramic!) film is grown on the surface of the material. The thickness and the structure of this film layer is responsible for diffracting light, which gives colour. Titanium can be anodised within a well defined spectrum, but achieving bright vibrant colours that are not "dull" is a strongly guarded trade secret. This is a function of the electrical voltage and current applied during the anodisation process, the temperature of the bath, the quality of the bath, the room humidity, how the raw surfaces have been chemically prepared and the overall process cleanliness... basically chemical magic. Unfortunately this is not something we can share. The faceted and feathered parts as well as the numerals are then assembled onto the freshly anodised dial by very lightly pressing the feet of the parts into the holes in the base dial. These dial feet are then laser welded from behind to ensure that they are secured strongly onto the dial. More on that process in a future installment! Next... Pad Printing (to be continued). NOTE: We have received a number of inquires in regards to the pricing of the MK2. It is obvious that the price will depend on the number of watches produced in a batch. Based on your pre-sale interest, we expect that the production run would be 50 watches at price of $6,900 (plus box and strap). Producing fewer watches would result in a higher price; making any more will choke our manufacturing capacity.  If you wish to register your interest, please send us an email to mail@clockmaker.com.au Unfortunately we are not taking deposits or partial payments. Once your watch is ready for delivery, you will be notified with sufficient time to make a full payment. More technical details will be provided next week, but for now: the MK2 is based on a Swiss made Soprod automatic movement, 40mm stainless steel case, on a leather strap. Titanium guilloche dial, markers and hands, as well as complete assembly is done 'in house'. Manufactured in Australia. A completely assembled MK2 "Curl Curl" topaz blue is available for viewing at our Sydney showroom. To check it out and try the watch on, please make an appointment.

Making the MK2 dial

Part 2

Last week we left you at the point where the CAM files were uploaded to the mill, the cutting tools loaded, and we were ready for action.  However, before we hit the start button, we need to step back in time for a moment. Making a watch dial out of Grade 5 Titanium is a complex but well defined process. The end result is not a mystery.   However the guilloche 'scribing' in the centre of the dial is something that is rarely done in Titanium. Actually there are only two other watchmakers who have released Titanium guilloche dials in the past.  The challenges are numerous. Guilloche is a scribing process - the tool does not rotate, like a drill or an endmill might. Obtaining a perfect cut is difficult even in soft materials like brass or gold. At the beginning of our project, we really had no idea if making a Titanium guilloche dial was even possible on our mill. Also, not every guilloche pattern produces an eye pleasing dial. The depth of the scribed line, the 'modulation' of the waves, the surface finish of the cut, and especially 'generation of the chip' are just some of the known unknowns.  There was only way to figure it all out: to start doing test runs and test cuts, then to tune the process and learn as you go. The very first step: the making of our own scribing tool.

The tool 'holder' is made from tool steel and the cutting edge of our tool is a detachable tungsten carbide tip. What you are seeing is a bunch of tools, making a tool to hold a tool to make a dial. The tool is made on the same milling machine that makes all the dials (the Kern!), starting from a sketch, design drawings, CAD and CAM files. But there is a twist: while the tool itself is made on a CNC machine, the tungsten carbide cutting tip, the part that actually does all the work, is sharped by hand and lapped on ceramic disc with a diamond slurry. Guilloche tools are definitely not off the shelf items, and this is not something we could order from Switzerland. If you can't make your tool, hand profile the cutter, make your own slurry, and sharpen it, no one else will do it for you. As an even more technical aside: The surface finish and edge sharpness of the tool itself directly correlate, 1 to 1, to the final surface finish of the guilloche. If you can sharpen and polish your tungsten carbide cutting tip to a mirror, then your guilloche will also be a mirror. Lapping the tool on a ceramic disc is the only way to do this. This is actually an incredibly difficult process to automate, and the fine feel and constant visual checks of a talented (human!) operator are the only way to achieve perfection. For example, the slurry on the ceramic disc needs to be constantly monitored- too much slurry, and the hydrodynamic forces take over and you end up "skating" over the lap, too little slurry and you run the risk of chipping the ceramic, or the tungsten carbide! Our toolmaker James is an expert at this process now, and after lapping many many cutting edges it takes about 30 minutes for him to achieve a perfect mirror on the tool. Once we had made the cutting tool, the first step was to cut a simple, straight line in a Titanium blank. If this was possible, and if we could achieve a good surface finish in just a straight line, then it would be highly likely that the next steps would be feasible! Below, you can see the first ever cut, and chip, of Titanium grade 5 made through a scribing process in our workshop, and I think it would be safe to say in all of Australia! With the know how of Titanium scribing safely in our pocket, we could start experimenting with guilloche patterns- to save prematurely wearing out the tool we did many of these tests in brass. Not every guilloche pattern is beautiful, in fact it's quite easy to make rubbish! But once we saw what we are calling "Curl Curl waves", maybe 20 or 30 test coupons in, it became clear that we had found our pattern!

Scraping: ready to cut test patterns in brass

As said before, not every pattern is eye-pleasing. The good patterns are those which are mysterious; patterns where the tool path is 'hidden' and difficult to work out. A pattern which makes the viewer wonder how in the world such pattern is even possible to make!

We settled for a wave pattern, which we immediately named 'Curl Curl waves'. Curl Curl is the closest beach to our workshop; and the name is said to come from an Aboriginal word meaning "river of life".

The moment of truth

The next phase we were ready to move to Titanium. The preparation starts with creation of dial blanks. A round bar stock is sliced in discs 4mm thick and 50mm in diameter on our Makino EDM wire cutting machine. Makin is 'the cutting edge of cutting': each cut provides the higher levels of precision and surface finish. The blanks undergo a heat treatment cycle to relieve the stress in the material. The exact parameters are something we constantly tweak, but in essence that material sits at 600 deg C for the better part of a day, slowly being brought back to room temperature.

Here is the shot of the first scribed line under the microscope. And even more important than the line itself is the chip: it's length, shape and surface finish tell us if our scribing tool is shaped and lapped correctly and whether the speed and depth of the cut are optimized for Titanium. Yay!

Dial manufacturing

The machining of the watch dial starts from the back side. One very special feature of the MK2 dials is that we make integral, or monolithic dial feet. Traditionally, dials are made from thin sheet, and have dial feet that are soldered onto the back. Having integral dial feet is a far superior method of making a dial: the feet are stronger, more rigid, and more accurately located. The trade off is that it's far more difficult to make a dial like this without it warping like a potato chip, and it's quite time consuming since you have to mill off quite a large amount of material.  Broken dial feet are a common problem for watchmakers and there is no practical way to solder back on a broken dial foot. Not with the MK2! Our feet will stay on the dial forever! In this photo you can see the back sides of the dial blanks being processed. Lots of material gets removed! Oil in the machine serves three purposes: to lubricate the cutting tool, to keep the workpiece and tool cool and stable in temperature, and to flush away the removed chips.

We make six dials at the time. The plate which holds Titanium discs is called a 'jig'.  Yes, we design and make our own jigs, in our workshop, specifically for the MK2 dials. Note that this particular jig is called 'number 7'.  When the back side is completed, the dials are now transferred to another jig for top side machining. In this step, we work on one dial at a time by milling away all but the raised section for the guilloche and the recess for the nameplate. The 0.2mm holes that will accept the numerals and hour markers are drilled as well.

After glass bead blasting to get a super smooth, even surface, the dial is then brought to the Kern Micro HD to do the ultraprecise, CNC guilloche of Titanium.

Part 3: Topaz blue, Curl Curl waves. Manufactured in Australia. To be continued...