Choosing a Donor Wednesday, Oct 28 2009 

So, what criteria should I use to be the heart and circulatory system for my prototype movement? Luckily I had had thoughts on this while designing a custom train over the previous years and worked out the following..

Firstly I want to use a robust train, large teeth on relatively thick wheels, (there goes the ETA automatics..) with a slow moving balance, large barrel for reliable power supply, and a large balance for resistance to minor disturbances

While using a donor movement I want to use one that has been proven to be reliable and robust in it’s own right, with any inherent flaws already discovered and fixed, or at least compensated for. (call me lazy if you want, but I’m going to have enough problems of my own)

The donor movements have to be readily available for a reasonable price, and be uniform in production. Unfortunately this rules out some brilliant movements by itself, I would love to use the Omega 30mm series, but trying to buy more than one in good enough condition is hard enough.. 5 or so that i expect to use, not likely! This also rules out some nice vintage calibres, early Jaeger, Piguet etc.. Due to cost, hopefully in the future I’ll be in a position to revisit this as a new project ala Kari Voutilainen and his Longines’ if I can find a suitable movement.

The movement components must be similar in dimensions to the movement I plan to make, as this will reduce my re-work time, hopefully by a considerable amount and will also simulate the pressures on components.

The movement components should be of good quality, in both materials and production. In my time at the bench I have seen watches disintegrate from within after one or two years of wear, when they have been made from inferior materials, which have worn out and then increased wear in additional components and so on. On the opposite side I have worked on watches that have been running for 20 years or more without maintenance and require little replacement or repair of parts.

With this criteria, and especially with a restriction on the amount I can invest financially, there is one stand out movement.

The Unitas / ETA 6497/6498, used by a remarkable variety of watchmaking firms, from house branded pocket watches to highly decorated versions in Omegas, Panerais and such.

Used for almost 60 years, while still evolving with new technologies, Nivarox balance spring, Incabloc shock absorption, Glucydur balance, all of these technologies have been added as they have come about, but the basic movement has remained the same. The movement is definitely robust, for the cost is quite impressively kitted out, and has numerous modules manufactured to give it additional functionality.

While I have worked on these movements before I currently do not have one in my posession, so will be waiting to obtain some to continue my project, as well as waiting on some tooling to measure components also (see next post).


Pictures from the Milling Process Thursday, Oct 22 2009 

These are pictures taken while milling my original prototype plate,

I am using a Sherline CNC mill, which while not the most accurate machine in the world, will I hope be suitable for my purposes..

The Initial Plan Friday, Oct 16 2009 

In this post are some of the initial renders of the movement I plan to make, all dimensions are custom, as I plan to make all components (using pre-made jewels, shock settings, hairspring and mainspring.)

Train as Originally Planned

Train as Originally Planned

This movement as designed uses a co-axial extra flat escapment, which will be re-designed to use the normal execution of the co-axial escapement as designed by George Daniels or a standard swiss lever escapement.

The movement as designed also uses a key-wind, key-set mechanism to remove any machining of the mainplate from the sides, due to limitations of my tooling and skills (This may change as i gather more skills).


I also have considered the idea of PVD black plates with blue sapphire jewels, which I quite like the look of.


Even without wheels made, I decided to machine out a prototype mainplate and upper bridges to check my machining ability if nothing else, they don’t look too bad. The dial side bridge/s definitely need rework however as the layout is quite messy, once I have my new measurements I will start from scratch again, while retaining as much as possible of the original design. (except the front plates)

First post, some background on why.. Thursday, Oct 15 2009 

To be perfectly honest it’s probably a silly idea to want to make a watch from start to finish, but I’m a contrary type of person. If it was easy to do then everyone would be doing it, and while I like the easy way as much as the next person, I feel that this could be my “thing” that people know me for.. 

I also keep having ideas for dials and case materials that I would like to try, which if I were to have made by other people would feel detached from, so learning all the skills required is the best way for me to try everything out…

While I would like to do the whole thing from start to finish in one go, from manufacture of all of the wheels, pinions etc. I sounded out Peter Speake-Marin on my basic plan while he was here in Melbourne on his world tour, with the following advice. (in relation to using a pre-made gear train in a newly made layout of plates)

 “If  you want to do it for yourself as a learning curve then make your life as easy as possible the first time and the learning process will be such that you still learn much along the way, finish the first piece in a shorter time, build your level of knowledge and confidence before designing every element in the second watch. “

One of the main reasons for doing this is to build additional skills prior to manufacturing all components, this will also let me see if my train layout will work, as the way i have planned it allows for maximum barrel and balance wheel size and the uses the smallest amount of space possible for the remainder of the train, this uses different lines of force from the original layout of most gear trains, which may have problems by itself. (The most efficient layout would be a completely straight line of force, similar to the Corum “Golden bridge” )

 I will also be changing the design of my movement to use the standard co-axial escapement as designed by Dr George Daniels, as opposed to the extra-flat version (also designed by Dr George Daniels) or for at least the first finished movement i may use a standard Swiss lever escapement.

As I now have to re-set out my movement from the start before returning to my original plan, I can show the progress as I go, unfortunately it also brings it’s own problems.. First off, which gear train to use?  How to convert the train to my design?  and most important… Would it look good?  

To be continued



Peter Speake-Marin

George Daniels


Video of Corum Golden Bridge

Corum Home Page