The Japanese (Seiko and Orient) typically have upwards of 20 seconds per day accuracy limit while the Swiss (ETA and Sellita) is much lower at just +/- 12 seconds per day. Why Are There Accuracy Differences Between Movements?įrom the above list, we can see there is a huge difference between Japanese-made and Swiss-made movements.
(You can read my previous posts about my Seiko SARB033, Sumo and SKX013 for some of the accuracy tests that I’ve done on the watches)
In my own watches, the out of box accuracy is lesser than +/- 10 seconds per day. This is because most of these movements are mass market movements and the manufacturers would like to play it safe with their published accuracy.īut real life accuracy shows that most of these modern movements can perform way better.
Sellita SW-200 (ETA 2824-2 doppelganger and used in Swiss low-mid range): +/-12 seconds per dayĪs you can see from above, the published accuracy range for most movements non-chronometer is usually very large. ETA 2824-2 (most commonly used movement in Swiss low-mid range of watches): +/-12 seconds per day. Orient F6922 (inside latest Orient watches e.g Mako/Ray II): +25/-15 seconds per day. Seiko 6R15 (inside Seiko mid-range of watches): +25/-15 seconds per day. Seiko 4R36 (inside latest Seiko low-mid range of watches): +45/-35 seconds per day. Seiko 7S26 (inside the SKX ranges of watches): +49/-20 seconds per day. Some movement can have small tolerance while others (the Japanese usually) can have a bit of large accuracy tolerance.īelow are the published maximum accuracy of some of the most popular automatic movements out there: While this is just a good guideline, the actual accuracy range depends on the movement itself. Without a doubt, you don’t want to have to set your time again more than once per week – that’s just too cumbersome even though I love to interact with my watches. This will correspond to about maximum +/-70 seconds per week, which means you will need to adjust your watch every 1 or 2 weeks, depending on how accurate you want it to be to the real time. To put this in perspective, the +/-10 seconds per day corresponds to 0.011% inaccuracy over the span of a day – which is still quite good in my opinion. In my opinion, the +/-10 seconds per day accuracy limit is a good benchmark for real life use. (It should be noted that accuracy rate is usually calculated as the average rate of accuracy over few days) I’ve arrived at the “good accuracy” value of +/- 10 seconds per day rate based on my own personal experience as well as many other automatic watch users. I would encourage the developers to revise their instructions to specify use of the earbud microphone only, and not the built in microphone.Automatic Watch Should Be Accurate To The Manufacturers Specification Also, keep in mind that the earpieces of the earbuds emit a strong enough field to affect a compass needle, so keep the earpieces away when using the microphone. 
An iPhone appears to be a bit safer since the speakers and microphone are on opposite sides of the device, but caution would still be wise. Although microphones do not create strong magnetic fields, speakers do create strong fields, and the speakers on an iPad are directly adjacent to the built in microphone.
#Using a watch timegrapher to regulate a watch professional#
I also purchased an earbud with a microphone, and am having more success obtaining reasonably accurate results, keeping in mind that this is an inexpensive hobbyists tool rather than a professional tool costing hundreds of dollars. After purchasing a demagnetizer, my watch now appears to be back to normal. Even worse, when using the built in microphone of my iPad, it magnetized my watch, causing a watch that typically runs at -1.1 sec./day to gain about 40 seconds in a day, and then to run about 5 sec./day slow. Initially, I had far more failures than successes in trying to obtain good data from this app.
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