Build & Servicing


OFFSHORE Professional chronographs combine traditional watch making skills with the latest laser cutting and CNC machining to produce completely unique timepieces.  Every component has either been designed and engineered from scratch or selected and modified based solely on the principle that only the best is good enough.  

The workshop is located at The Clock Gallery, 147 Pitshanger Lane, Ealing, West London. W5 1RH. Tel 0754 251 3984.

Darius (above) runs The Clock Gallery and as the name implies, he spends a lot of time servicing and repairing old clocks.  He's also a master watchmaker who learned his profession on the Valjoux 7750 family of movements.  The 7750 is one of the worlds finest watch movements, combining longevity with robustness and accuracy. Key to its strength is that it is built as an integrated chronograph.  


The best watches deserve the best watchmaker and so all OFFSHORE Professionals are built by Darius in his immaculate Ealing workshop. Darius also makes the movement modifications necessary to incorporate the unique day and date arrangement, adjusts timing accuracy to within chronometer standard, and then assembles each watch absolutely perfectly.  


When it comes time to service and re-lubricate your OFFSHORE Professional then just give Darius a call.  

In the background of the top picture is Paul, a Rolex specialist. Between them Darius and Paul can service and repair just about any make of watch, and will even make parts for long discontinued movements.

A basic service and lubrication for your Field Engineer can be done by any competent watchmaker, just check they have experience with the Valjoux 7750 family.  For servicing, plus any additional work such as upgrades and repairs outside the warranty period, then call Darius.  All Field Engineer chronographs can be upgraded to the latest specification including new hands, dials, and the addition of day as well as date windows. The Clock Gallery holds a large inventory of OFFSHORE Professional spares to ensure fast and efficient repairs and servicing for many years to come.

Movement

The Valjoux 7750 chronograph movement fitted to the Field Engineer will run for 5 to 8 years between servicing.  Servicing can be undertaken by any competent watch maker, although of course I recommend you use Darius at the Clock Gallery.  Servicing consists primarily of refilling the reservoirs in the jewels with lubricating oil. If you look closely at the jewels (the light purple coloured rubies in the photographs) you'll see a small dot at their centre. The rubies are manufactured rubies made from crystals of Aluminium Oxide with a trace of Chromium and have a central hollowed out area to hold the lubricating oil. Like the sapphire front and back glass they have a mohrs hardness of 9 and so should quite happily last for several hundred years before showing any signs of wear. 

Failure to service your chronograph will not damage it, but may cause it to run a little slower as the lubricating oil dries out and internal friction increases.  All the main bearings are jewelled with rubies so their friction surfaces are extremely hard wearing and will take many years of completely unlubricated wear.


Over the years you may find the time keeping of any mechanical watch wanders slightly outside its original limits, an effect generally caused by changes in lubricating oil viscosity with temperature and oil manufacturer.  On the 7750 there is a small adjuster that will increase or decrease the balance spring length to compensate for this. It's visible on the picture above as a graded scale with a + and - symbol. Adjustment should only be done by a professional watch repairer as it is altogether too close to the balance spring (the helical spring behind it) to take the chance and try it yourself.


The self winding rotor runs on 5 ball bearings just visible at the very center of the movement.  When it rotates in a clockwise direction it winds up the main spring.  It takes 700 complete clockwise revolutions to wind the main spring from empty to full, typically accomplished with 4 hours of normal wear.  Once fully wound a simple mechanism prevents the main spring from being overtightened.  The self winding rotor spins freely in the anticlockwise direction, and a rapid flick of the watch can create the famous 'Valjoux wobble' where the self winding rotor spins so fast it makes the whole watch imperceptibly wobble.  The Valjoux wobble is a great reminder of the beating machine running on your wrist.  The self winding rotor bearing will last for several hundred years of active wear before the ball bearings come loose, so you can quite happily flick your wrist to feel the wobble whenever you fancy.  As a side, it is fun to flick other peoples mechanical chronographs to feel for the wobble.  If you do feel it then you can let them know their IWC, Omega, Breitling, Panerai etc is built from the same base movement as that running in your Field Engineer.  The one in your Field Engineer though is quite likely to be to a higher standard of execution.


Parts count in the movement is a little over 110 or around 300, depending on how you count them (5 ball bearings, 3 rings, a rotor bolt, 2 rotor parts and a screw = one self winding rotor).  It's probably close to 400 if you start counting all the dial components, hands, movement holder and fixings.


Magnetism

Although the movement has non magnetic components at all key locations and a Faraday compliant outer case design, as with all mechanical instrumentation, it is possible for the timing to be affected by strong magnetic fields.  The electro magnetic fields (EMF) present in modern day life will not affect it unless the casing is held very close to a strong EMF transmitter for an extended period.   


You can check for magnetism in any mechanical watch by holding a compass up tight to it.  If the compass needle moves a little (a quarter or half way around its dial) then your watch has picked up some magnetism.  The Field Engineer to the right has been deliberately magnetized to test the movement accuracy is not affected.  Demagnetizing is a very simple process using a special machine that most watch repairers will have to hand.  A demagnetizing machine applies a very strong magnetic field to the watch, but then rotates the field in a chaotic way so it has no preferred alignment.


Case

The inner case, also called the movement holder, is made from soft copper and plated in rhodium.  It is visible in the above photograph as the three matt silver outer rings.  Minor shocks to the watch either never reach the movement due to its mechanical isolation or are absorbed through elastic movement of the incabloc mechanisms fitted to all main bearings. Really big shocks are absorbed by the movement holder. Above a certain limit it is simply not possible to absorb impact energy elastically, so a plastic movement is required.  This is plastic in the engineering sense, not something made from plastic (nothing in the movement is made from plastic as it becomes brittle with age).  A big impact will also cause the sub-dial hands to detach as they sit on relatively slim spindles which require full movement strip down to replace if they bend.  The sub dial hands can be reattached, movement holder checked and replaced if necessary, and your chronograph should then start running again perfectly.


The Field Engineer outer case is made from solid 316L stainless steel with sapphire front and back 'glass'.  Over time the stainless steel will pick up small scratches which can either be left or polished out.  You should try and keep the push buttons and base of the crown free from substances that could work their way into the seals, generally anything too guey or fine powders.  This is partly to prevent these substances from slowly working towards the seals where they might create a leak path, but primarily because a dirty watch is a horrible thing to behold.


Parts count in the case is just under 30 including the movement holder locking.




Bracelet

The bracelet links, body and butterfly clasp are made from 316L stainless steel, with the double headed screw pins from 316H. L is low carbon (<0.003%), H is high carbon, with increased carbon giving higher strength but lower toughness.  H is ideal for small components and in particular for screw threads, L is ideal for case and bracelet.  The bracelet needs no maintenance other than the odd clean with a soft toothbrush to get any dirt out. Adjusting the bracelet is by removing links as shown below:



The screw pins that hold the links in place are double ended, with the small screw going into the larger one.  This can make adjustment quite fiddly but it ensures the connection is much less likely to come loose.  Because of this fiddleiness it is recommended that adjustment is done at a local jewellers. Parts count of a bracelet is bloody hundreds of fiddly little bits, many of which are lying in dark corners of my study. (about 250)


Strap

The outer surface of the strap is made from leather and, just like shoe leather, it benefits from a polish every once in a while.  The best polish to use is simple black shoe polish.


Eventually, and just like a good pair of shoes, the strap will become tatty and wear out. Hirsch make the Field Engineer custom straps and I ensured the end fitting is to their standard dimensions so that any of their 22 mm curved end straps can be substituted.


This interchangeability allows you to use different colour Hirsch straps if you feel like a change.  Elsewhere on this website you'll see pictures of Field Engineers with blue and brown Hirsch straps.  Parts count on a strap is 10.



Buckle

Like the case, the buckle is made from solid 316L stainless steel and requires no maintenance.  Adjusting the buckle is done by flipping the trident overpiece up with your thumb, moving to the required strap hole, and then snapping back together.  The unsnapping and resnapping of the overpiece is deliberately firm as this is an operation you'll only ever do once or twice. Parts count is 14.


A mechanical chronograph is an expensive investment, and one it can be very difficult to justify when compared to the much cheaper battery powered quartz, digital or smart phone alternatives.  I want your Field Engineer to last a lifetime and so have done everything possible to make it really live up to the tag line of Quality, Strength and Performance.  

Total number of parts that make up a Field Engineer = about 750.

Quality, Strength, Performance