cazalea[Seiko Moderator]
17061
Degrees, Gears & Ratios, Part 1
Sep 12, 2022,18:10 PM
Degree is a very complex word in English, with many meanings:
- a unit of measuring temperatures, as in 40° C
- a unit of measuring rotation, such as "a right angle is 90°"
- a measure of technical difficulty of skill in an athletic competition, such as gymnastics or high diving
- a certificate given for completion of a course of study
- distance between people who know one another, as in "there is one degree of separation between myself and the new King, because I know Richard and Richard knows the recently-crowned King Charles.
Today I propose to take a look at the degrees required on a watch dial.
I'm using my perpetual because it has multiple subdials and complicated
divisions.
Here you can see I have divided the dial into 12 segments (hours) with green lines.
Each line is 30° of rotation from the previous line (30x12=360 or a full circle) and each line represents 5/60th of an hour.
I overlaid some more lines and it became too complex to explain, so in the right-hand example below I subtracted the dial itself so we can just concentrate on the lines and circles.
SMALLEST purple circle is divided into 12 months (360/12=30°) and 24 half-hours (360/24=15°). This circle is smaller than the distance between the green (12th) lines.
LEFT light blue circle is subdivided into 7 days (360/7=51.42° of rotation) and 60 seconds (360/60=6° of rotation). This circle just touches the green lines.
RIGHT light blue circle is divided into 31 days (360/31=11.61° of rotation). This circle also just touches the green lines.
LARGEST red circle at 12 o'clock traces the opening cut into the dial, to display the revolving, twice-a-month moonphase subdial (2 x 29.5=59 so 360/59=6.1° of rotation) and a 30-minute counter for the Chronograph (360/30=12° of rotation). This circle is larger than the distance between the green lines.
The centers of these sub-dial circles are equidistant from the center point of the dial, so they fall on the circumference of the orange circle below.
Notice that I haven't defined the LARGEST dark blue circle. It needs a drawing of its own! The items outside the pink dotted line were left off or buried under something else on the dial. And I got bored with creating the diagram and didn't put in the outermost display -- would you say those are seconds markers?
QUESTIONS
Now I have to ask: which part of the watch manufacturing process has the greatest "degree of difficulty" (in your humble opinion)?
- Designing the overall dial concept / design
- Executing the detailed degrees/rotation/size design of each of the markers on dial and sub-dials
- Making the dial base, then printing, positioning & lume coating the dial markers, windows, etc.
- Making the movement underneath operate correctly and have its arbors sticking up in the right places to rotate the hands
- Making sure the movement frequency (let's say 28,000 vph or 4 per second) is evenly divisible so the chrono hands line up with the marks on the seconds scale
- Can you give an example of any watch you own where the manufacturer FAILED to properly execute these 5 factors?
Thanks for reading, and please come back for Part 2 of Degrees, Gears and Ratios.
Cazalea