Should Automatic Watches Rattle? (or Should You Worry?)

There can be a great reason to worry when you start hearing noises that you usually don’t hear. For most new automatic watch owners, they will experience their automatic watch making some weird noises. Most people are adjusted to the single tick per second of quartz watches. However, some sounds are totally normal, and some noises should be dealt with.

Automatic watches have a rattling noise caused by the bearing connected to the rotor and winding mechanism. The rotor is connected to the bearing to move freely, and bearing has a metal-like scraping noise. Often there is no reason to worry about a rattle.

While the rotor is an entirely normal metallic sound coming from the automatic watch, some sounds indicate that the watch might be damaged. Some noises mean you need to visit your watchmaker, and some noises is just the sounds of automatic watches.

Why do Automatic Watches Make Noises?

The noise you hear from your automatic watch is most likely the rotor that moves while winding your watch. If the noise/rattling you hear reminds you of a fidget spinner’s sound, you have no reason to worry.

In the center of the movement on an automatic watch is where the rotor is connected, which rotates as the wrist is moved. The slight rattling/metallic noise coming from the watch is the rotor moving.

Several different noises is coming from your automatic watch. The normal sounds include:

Whenever you are moving your wrist or shake the watch, you will be forcing the rotor to move, which is what winds the watch’s movement. The whole difference between a manual and an automatic watch is the addition of the rotor which is winding the watch manually.

Therefore, it’s completely normal that the rotor is making as rattling/metallic noise when rotating. If there is no noise coming from the watch, the rotor might not work properly.

Rotor and bearing on an automatic watch
Rotor and bearing on an automatic watch

Furthermore, automatic watches is a compilation of metal components that pushes each other to drive the second, minute, and hour hand around. From your regular quartz watch, you will recognize the once per second tick, tock, tick, tock. However, automatic watches don’t beat once per second. As a matter of fact, they beat between 4-6 times per second.

Therefore, you can expect to hear some unfamiliar noises which have a characteristic of a fast tick, tick, tick, tick, tick at the rate of 4-6 times per second. In addition to the “tick, tick” noise, you will most likely also hear a fast metallic scraping “shhh” noise from time to time. The sound of the watch ticking is not very audile, and therefore you have to listen quite carefully to notice it.

The fast “shhh” noise comes from the mainspring, which is located in the mainspring barrel. The “shhh” sound is what is typically referred to as the slip-clutch, which prevents overwinding.

To give a brief background, the mainspring is what retains the energy in the watch. The mainspring is wound through the movement of the wrist or by turning the crown. To prevent the mainspring from snapping, there is made a small advancement which is called the slip-clutch.

The mainspring in an automatic watch has a y-shape. The reason the mainspring is y-shaped is that the mainspring is folded in the side of the y-shape. In other words, the right side is attached to an axel that is winding the mainspring (in watchmaking jargon, called an arbor). Whereas the left side is not connected to anything.

Therefore, the y-shaped end can slip freely when the mainspring has built to much torque. The y-shape portion is “folded” inside the barrel, making it push against the mainspring barrel’s wall. When the mainspring is wound, it will start to contract, and when the y-shaped fold experience to much torque, it will spin, making the “shhh” sound as it unwinds. This whole mechanism is often referred to as the slip-clutch.

Mainspring-of-a-watch (Credits: Hustvedt)

The reason for the mechanism of the slip-clutch is to avoid the mainspring from snapping in half. Using the mainspring barrel’s wall and the mainspring’s y-shaped end to control the force allowed is an easy and effective way of limiting damage to the mainspring and maximum torque.

Lastly, another common noise you will hear from an automatic watch is the crunchy, metallic sound when you are winding or adjusting the watch. This grinding noise can sound troublesome. However, it’s perfectly normal when a well serviced watch. In the video Hodinkee made with John Mayer, you will see and hear 1 of john Mayer’s watches produce a metallic grinding sound (video below).

John Mayer and Hodinkee talking watches

Regular automatic watches will not produce as crunchy as you hear in the video. However, you will be able to hear something similar. The noise simply comes from the whole gear train in the watch moving. You will not hear the gear train moving when you are wearing the watch since it’s moving significantly slower, compared to when it’s wound or time is adjusted.

Signs the Automatic Watch is Damaged (What Causes the Noise?)

We just discussed why automatic watches make noise and if it should be allowed to or not. Oftentimes you really don’t need to worry about a little rattling sound from the watch since it’s most likely the rotor spinning.

Nonetheless, automatic watches can make sounds which is not wanted. One of the noises sounds very familiar to the sound of a rotating rotor. The noise that is close to indistinguishable is when the rotor axel has problems. There is a little trick that might reveal if you have this issue.

If the watch is rattling with a scraping noise, the rotor will most likely have damage in the bearing, or the screw holding the rotor in place has become loose.

When a bearing is bad, or the screw to the rotor has become loose, there is only one thing to do: to go see your watchmaker and get it fixed. However, to correctly identify if the rotor is damaged, you will be shaking your watch.

Video showing rotor that has been scraping on the case back of a watch

If you have a clear case back on the watch, you are in luck. You will be able yo see right into the heart of the watch to identify whether the rotor is scraping or not.

If you have a clear case back on your automatic watch, you want to be looking for a black-ish scraped circle that aligns with the rotor. Depending on how damaged the rotor is, you will be able to see anything from a light grey color grading to a dark color grading. At times you might even experience the rotor being stuck.

If you don’t have a clear case back, some other indications could point towards a broken rotor. If you experience your watch is stopping overnight, it can be an indication that the watch is not winding properly. Hence the rotor might be broken. A regular automatic watch will have a power reserve between 30-70 hours (on a full wind).

Should you Shake an Automatic Watch?

There are some misconceptions about how to wind an automatic watch. Many will say that an automatic watch should only be worn to be wound, others will say that you should wind the crown every morning to make sure the watch is fully wound. However, many think that getting the watch started by shaking it can damage the watch, which is incorrect.

Shaking an automatic watch is a good way of winding the watch as it mimics the movement of your arm. Shaking an automatic watch doesn’t cause any damage. Shaking the watch for 20-40 seconds will be good to get the watch going before wearing it.

The rotor is made to wind the watch when the watch is worn. However, if your watch has stopped, you will need to get some power into it, before adjusting the time (otherwise, it will be behind when you are done adjusting the time).

Shaking the watch for 20-40 seconds is a good way of building the initial power reserve before adjusting the time and putting it on the wrist.

Sometimes when the watch gets sticky to your skin, you might also just do a quick shake with your wrist to get the watch of your skin (I know I do). This movement doesn’t cause any damage to the watch, and watch manufacturers wouldn’t make a watch that could take damage from such a movement. Imagine doing any active activities if the watch couldn’t handle to be shaken.

Jonas Henriksen

AllInWatches is founded by Jonas, who has a great interest in mechanical watches. All aspects of manual and automatic (mechanical) watches is a big interest and have been a passion since 2015, where the first automatic watch was purchased. Seeing the transparent case back and discovering the heritage of watchmaking piqued an interest in horology.

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