WatchTech

A David Walter Double Pendulum Clock
    – Part 10,  A Milestone is Reached - The Equation Movement Finished

Every week we are seeing more of David's work on his new double pendulum clock.

A milestone has been reached, the first movement, the equation movement is now finished.

For those of you who didn't see the earlier installments of this series, you can catch up by looking here:
    - Installment 1 – Introduction and Cutting out the plates
    - Installment 2 – Making the Barrel
    - Installment 3 – The Suspension
    - Installment 4 – Invar Pendulum Parts
    - Installment 5 – Making the Wheels
    - Installment 6 – Completing the Barrels, Cutting some Pinions
    - Installment 7 – The Escape Wheels
    - Installment 8 – The Mean/Solar Movement Main Train
    - Installment 9 – The Equation Wheel


We can hear Davids elation in reaching this milestone.  Let me simply quote his email to me:

“Hi Don,
Sorry only a few pics, I was buried in the making.

At last ! The Equation is complete !

Reaching this point is a milestone in the project, I have the entire
equation work finished.
Part of what felt like it was taking longer than expected is that this
time I undertook the finishing as I progressed which includes polishing
the brasswork, polishing the foot and head of each screw, shaping,
beveling and matting the cocks, as a special for this clock I have
blued the steel springs and fitted steel locating pins with polished
heads to the springs and polished screw heads for the steel springs and
blued screws for the brass cocks.
This time I am finishing as I go, I know I may well have to apply some
final finishing once all is done, but at least I wont have to sit down
at the end and polish 700 + parts and screws one after !

I have also designed a new manner in which the year wheel is indexed
which is less complicated and I feel a little more positive in action.

Not only is the equation work complete but the Thermometer arrived today. 
This clock will have a thermometer inside the case.

Now I need a break, I feel quite worn out at the moment.

Best regards,
David”

No message body

Is it my sherry or my eyes deceiving me?

The one on the left is not perfectly round

The all will appear less wonky.

That is the equation cam, sometimes called the kidney cam due to its shape.


David

...on the equation kidney?

I think it is. I have thought of trying that myself eventually, when I get a chance to make equation works someday.
I see yet another "1st" has already been done by someone else.
Not disappointed- it must have been a good idea if David actually did it. It looks rounded, but is it a large radius,
and having a flat on it to ride the whole circumference of the kidney profile, so the kidney wears evenly?

Curious- what is this new method for indexing a year wheel? I don't quite see it yet, other than a standard detent.
I must be missing something, unless it's not installed yet..

Some of us are paying very close attention to this. Very close, but not commenting on everything, maybe.
I myself am still pouring over every picture as the work comes together, fortunately seeing a lot I understand, and everything inspires.

It really is a wonderful thing you have brought us Don- thank you and David both. To see someone post updates to
a work in progress like this, and of this caliber- is unparalleled.
This message has been edited by Ophiuchus on 2015-08-31 18:27:46

a ruby rod, the end is slightly bull nosed as it must follow the cam at varying radii.

On earlier clocks I had a long lever indexing the year wheel from the left hand side, this worked well but
the long lever had more mass, the new version is much lighter.


David   

David

The real story - how it works

Hi Don,

Explanation;
I have attached a pic of the movt. upright as this is how it appears on
the finished clock and it is somehow easier for me to explain if its the
right way up.

The wheel immediately above the cam wheel at 6 o'clock is the center
wheel, ie revolves once per hour, there is a steel detent fitted to it's
shaft which indexes the 24 tooth wheel to the immediate right once per
hour to make 1 full turn per day.

The 24 hour wheel has a steel pin (visible at 11 o'clock on the wheel)
this pin lifts a short lever on the 2 armed date change lever pivoted to
the lower right of the 24 hour wheel. When the lever is lifted by the
pin the upper arm of this lever (seen at 8 o'clock) swings to the left,
the top arm has a hooked spring which gathers one tooth of the year
wheel carrying the cam and rotates it anti-clockwise. The year wheel has
365 ratchet shaped teeth.

The pivoted cam follower rests against the cam at 9 o'clock and is
fitted with a red sapphire rod, the upper end of the following lever has
a pivoted steel flag. A hard steel shoulder screw passes through a
jewel fitted to the flag holding the flag in place, the lever following
the cam moves the flag in and out during the course of the year.

A click with a long tail seen at 6 O'clock on the equation wheel sited
just above center in the movt. photo (see earlier pics for the
equation wheel in detail) comes into contact once per hour with a sprung
release post seen at 1 o'clock this releases the ratchet, the two
quadrants now spring into action permitting the flag follower to come
into contact with the steel flag. The equation hand will now display
the correct setting for that time of the year.

The hour, minute and equation hands are on the same axis, the equation
hand rotates with the minute hand and indicates the equation of time by
being either ahead, behind or equal the minute hand.
The equation hand will be 18K gold.

David

It's a bit difficult to make out all the details exactly from the picture, as zooming in on pins and such
just gets blurry, but the explanation, coupled with what I can make out, and my knowledge of this type
of equation mechanism from Daniel's books, especially The Art Of Breguet, makes sense.

Thanks Don for bringing us the details of David's very technical setup!

Would love to see an HD video of the equation mechanism self adjusting, and indexing... this is
one of those mechanisms that ought to be really beautiful to watch, but you'd normally never see
it doing it's thing in action. The pictures and explanations are plenty wonderful enough, though.

David, I know the making of watches and clocks is a huge task, and interrupting that work for photos and commentary adds to the effort. I hope it also provides a welcome distraction, or at least adds a sense of satisfaction that you (together, as Don too is laboring) are providing education and pure enjoyment to us here.

Looking forward to more!

Mike