Movement and jewel

[henry2703]

Hi guys.... i came across the below in an article...

"Jewel bearings were used widely for mechanical (escapement) watches, where their low and predictable friction improved watch accuracy. A typical mark of watch quality was a note such as "17 jewels". More jewel bearings often meant better precision. Some makers added non-functional or unnecessary jewels to give the impression of accuracy. Some watches had 100 jewels, most of them of no use. A typical "fully jeweled" time-only watch has two cap jewels, two pivot jewels, an impulse jewel for the balance wheel, two pivot jewels, two pallet jewels for the pallet fork, and two pivot jewels each for the escape, fourth, third and center wheels. Modern electronic watches achieve accuracy entirely separate from the friction of the mechanism, but early quartz watches used jewels to increase battery life, and high-grade quartz watches use jewels to reduce friction and wear."

I am just interested to know... that since 17 jewel is enough... in a 3135, where there are 31 jewels, are the extra 14 jewels just "to give impression of accuracy"

[JJ Irani]

The extra 14 jewels only means that you are looking at a more complicated watch with more moving parts.

Each jewel acts like a "ball-bearing" and is functional in reducing friction between moving parts.

Some designer watches throw in jewels just for the heck of it using them as a sales pitch.

In a Rolex all 31 jewels are FUNCTIONAL - none of them are extra or redundant.

JJ

[padi56]

Yes agree in the 60s the watch jewel war started,my watch has more jewels than your watch etc,some boasting 100 jewels most just for decoration..Now 15 jewel and 17 jewel movements are mostly manual wind.But most auto movements today are 21 or 25 and above,now a 15 or 17 can be just as accurate as 31 or more.Like JJ said the jewels today are only needed on the friction moving parts.But have more jewels don't mean that movement is better that one with less.Its a bit like todays computer hard/drives now getting bigger daily but bigger don't always mean its better.

Below is picture of a Waltham of the period boasting 100
jewels but in reality only 17 in the actual movement.Its is
possible the the jewels in the rotor could have helped the winding rotor wind more efficiently. But IMO would seriously doubt it just a boast that I have more and I am better than you complete and utter pure hype marketing,a bit like the Swiss COSC test today.

http://img213.imageshack.us/img213/7963/100jewels5bi.jpg (http://imageshack.us)

[Edensknight]

JJ and Padi: Great supportive and informative responses! And, it is very true that the deciding factor IS the actual number of jewels functional within the movement itself that is imperative. Great info! :thumbsup: :cheers: