Advantages of Watch Jewels in Watch Movements

January 26th, 2010 | 9 Comments

To drive timekeeping in mechanical watches, a watch escapement converts continuous rotational motion from the spring into a harmonic back and forth motion.

A watch escapement includes three main parts:

  1. Balance wheel
  2. Balance wheel staff
  3. Pallet lever


Each of these main parts contains jewels, which serve different important functions.

There are 4 types of jewels:

  1. Hole Jewels, donut shaped jewels that go over the gear axles
  2. Cap Jewels, flat jewels on the ends of the axles
  3. Pallet Jewels, brick shaped jewels on the pallet fork that engage and release the escape wheel
  4. Roller Jewel, which is on the large oscillating balance wheel and engages with the pallet fork on the end opposite of the pallet jewel

Typically, the jewels used in watches are synthetic or natural, such as rubies, sapphires, garnets and diamonds. More jewels often means a higher watch cost, but not because of the value of the jewels. Rather, this is because the jewel count is an indicator of quality.

There are 2 distinct advantages of watch jewels that lead to increased quality:

1. Accuracy

To increase accuracy, watchmakers make reducing friction an important goal.

They can use jewels, which have 2 properties that help with this goal:

  1. Smoothness, which lets the metal parts slide easily
  2. Hardness, which prevents quick wear

Specifically, precision-made watch jewels hold oil in pivots, which reduces friction on pivots. This allows the gear train to run with greater ease. A reduction in friction reduces the amount of power required from the mainspring. This allows the watchmaker to use a longer, finer mainspring that allows the watch to run for 40 hours on a single wind. As a result, some watches even feature a power reserve indicator that displays the amount of power left (in hours) on the face of the watch.

orange metal

2. Durability

Most modern watches use synthetic sapphires, which are very hard and durable. Sapphire surfaces can maintain smoothness over decades of use, reducing friction variability.

Therefore, a watch with jewels will usually not wear out as quickly as one without jewels. Sapphire also helps accuracy, because the coefficient of friction of brass-on-steel is 0.35, but sapphire-on-steel’s is about 0.1.

small diamonds

While watches with more jewels tend to be of higher quality, some watch manufacturers have taken advantage of the general public’s connection of jewels to luxury by adding non-functional jewels.

However, a typical fully-jeweled watch has only 17-21 jewels. Don’t be fooled by companies who claim that their mechanical watch with 50 jewels trumps one with fewer jewels.

  1. 9 Comments | Tell us what you think!

  2. By Steve Poorman on Jan 26, 2010

    You answered one of my questions I asked in a previous article. (what types of jewels were used in watch construction). Thanks, great article!

  3. By Micah Causey on Jan 26, 2010

    Please include me on newsletter and any Deal of the Day offers.

  4. By Les Florance on Jan 26, 2010

    You have defined fully jeweled movement to separate quality watch making from hype or scam, those containing more jewels which serve no function but to increase the asking price.

  5. By Julian Salas on Jan 27, 2010

    hello, I’m Julian i live in Mexico and I am interested to know how common is a clock that I inherited by my grandfather many years ago,is an orient with serial number is 80903551 and it has a legend in the back that says anti shock 904511, I will be grateful for any information
    can provide.

    Julian Salas Borrell

  6. By ORIENT Cassie on Jan 27, 2010

    Hey Julian! Thanks for sharing. We’ve emailed you personally to ask if you have a photo of the watch and can’t wait to help you learn more about it!

  7. By Y.CHAKRAVARTHY on Feb 27, 2010

    There are three types of hole jewels
    1.hole jewel with cup to retain oil
    2.big hole jewel without cup
    3.olive hole jewel used in escape movement

  8. By P. Allred on Aug 24, 2010

    Do you offer a replacement for the ETA 2894-2 auto/chrono movement? It is automatic, and the eyes are at 3,6 and 9. do you have other alternatives that will apply to the Omega Speedmaster Professional? If so, advise details, including cost. Thank you.

  9. By Lukas on Feb 27, 2014

    Dear All, I bought recently used Orient watches with designation 904511 and when opened they have there imprinted a year of making of that big moving weight. It says 1942. So it is logicall to assume they are not older, but also common sense would suggest parts would not be probably stored more than 10 years.

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