Miyota calibre 9015 service walkthrough, review and ETA 2824-2 comparison

[VWatchie]

Miyota Calibre 9015 Disassembly

Miyota Calibre 9015 Assembly

A few words about this walkthrough

The disassembly pictures do not contain any close-ups of the screws. However, the assembly pictures do.

I couldn’t find any oiling suggestions for this movement, so I’ve used my own experience to determine what oils to use. If you want to contribute your own oiling suggestions, I would be very interested. I’d even be willing to update the pictures.

To avoid over-oiling posts and bearings, I oil them after the parts have been assembled. Once I see that the oil has spread around the post or bearing, I know it’s sufficiently lubricated. That’s why you’ll see my oiling suggestions after the parts have been replaced.

A nice feature of the Miyota 9015 is that it doesn’t contain any parts that are tricky to handle, so in this respect it is a straightforward movement to service. However, it contains many parts (see the video), so this walkthrough will, I’m sure, facilitate the job.

The movement itself, isn’t stamped with the Miyota logotype or calibre number. Instead, this information is found on the top of the oscillating weight unless the movement has been branded, like in my walkthrough example (Ingersoll).

Please note that this walkthrough is not a tutorial. I make these walkthroughs for my personal use, although I’m happy to share them. The idea is that the next time I service or repair the same or a similar calibre, I can focus on the job rather than spending time on figuring out what goes where and why. Also, making a walkthrough you get to understand the movement quite well.

If you have no experience, you should know that there are a few things you need to learn and understand before you can successfully service a watch movement. It is not "rocket science", but it takes some effort, perseverance, and practice. It also requires some watchmaker tools and oils. If you want to learn how to repair and service watches on-line, I recommend watchfix.com, learnwatchmaking.com, or timezonewatchschool.com, in that order. I’ve enrolled to all these courses, and they are all good, but in my opinion watchfix.com is the best and most affordable. And no, I’m not affiliated with watchfix.com, watchrepairtalk.com, or @Mark (who’s running these sites). There’s also nobswatchmaking.com and perhaps some other… but I have no experience with them.

Background and Miyota 9015 vs ETA 2824-2 comparison

In 2015, before I knew much about watch movements at all, my greatest watch dream was to own and wear a vintage Blancpain Fifty Fathoms Aqua-Lung Diver, but not having the USD 25,000 or so to spend on a watch I decided to look for an affordable homage. Eventually, I found the Helson Skindiver (still available for USD 699). Nevertheless, I was hesitant to pull the trigger. Why? Because it housed a Japanese movement! To be more precise, a Miyota calibre 9015. That was not what I had in mind for a watch with a price tag above USD 500. I wanted a Swiss high-quality movement, like the ETA 2824-2. In the end, however, I decided to take a chance, make or break.

The Japanese Miyota calibre 9015 is presented as a premium movement, and it even comes pre-decorated with Côtes de Genève (Geneva stripes) and a sun-burst rotor. It is housed in many of the more expensive micro-brand watches, like the mentioned Helson. I’ve heard people call it an "ETA 2824-2 killer", but it only costs about USD 100 or even less. So, the question is, does it live up to what it promises?

Getting into the details of this movement I was surprised to see how many sections of it were like or inspired by the ETA design. That is the gear train, the dial train (motion works), and the keyless works look a lot like an ETA. And just like the ETA movements, and unlike many other Japanese movements, the Miyota 9015 contains exactly zero plastic parts. If I had not known that this was a Miyota, I would have thought it was a new ETA prototype as it is also thinner and overall looks and feels more modern.

A major difference between the 9015 and the 2824-2 is the automatic works. In the 9015 the barrel, the gear train, and the automatic works are all held in place under a single bridge. In the 2824‑2, on the other hand, these sections all have their dedicated bridge. The single and decorated bridge of the 9015 looks nicer, but there are a lot of pivots, wheel teeth and pinions (also fitted and secured under the bridge) that must fit and mesh before the six bridge screws can be secured. Luckily, the precision of the parts is so precise that it doesn’t pose a problem. One just must be a bit careful and observant.

Another difference is that the oscillating weight (rotor) of the 9015 is unidirectional, whereas the oscillating weight of the 2824-2 is bidirectional. That is, the oscillating weight of the 9015 only winds the mainspring in one direction, whereas the 2824-2 winds in both directions. For this reason, I assumed that the automatic winding of the 9015 would be less efficient than that of the 2824-2, but in practice, I quickly learned that this is not the case. Even after a somewhat lazy day I never get less than the specified 42 hours of power reserve.

So, how does this Miyota 9015, 28.800 BPH perform as a timekeeper? Well, the largest difference in variance between two days that I’ve measured is 1.9 seconds. Well-regulated this means that the 9015 has the potential to be as accurate as any COSC certified watch. I don’t mean to say that it would pass the extreme tests of a COSC certification (not without some modifications), but under normal circumstances, that would apply to most wearers, it is up there with the best.

Getting back to my Helson Fifty Fathoms homage from 2015. How did it perform? In one word, perfectly! I was so happy with it that when waking up in the morning I made it my first priority to get it on my wrist, even before my underwear. Anyway, it was up for a service, and as I didn’t want to take any risks, I decided to buy the least expensive used watch housing a Miyota 9015 I could find on eBay for practice. After some looking around, I found a used "Ingersoll Empire State". That is the watch I used to create this walkthrough. Another strategy could of course have been to simply buy a new or used 9015, but it is always more fun to buy a complete watch, and to service a watch movement.

So conclusively, does the Miyota 9015 live up to its promise of being premium? If you ask me, in one word, yes!
 

Edited August 2, 2021 by VWatchie

[VWatchie]

Miyota Calibre 9015 Disassembly

 

[VWatchie]

Miyota Calibre 9015 Assembly

 

[Nucejoe]

Excellent presentation as usual. 

[Nucejoe]

Excellent presentation as usual. 

[HSL]

Indeed, a very nice walkthrough!

[Zero]

This service walkthrough is so well done, its like looking at an artwork.

[VWatchie]

21 minutes ago, Zero said:

its like looking at an artwork

Wow, thanks! 

[ifibrin]

That’s a very nice walkthrough. I might get a Miyota to practice with!

I was wondering myself whether it would be better to lubricate wheels on posts by first putting the wheel on the post, then touching the Oiler with oil to the interface between the post and wheel hole. Never seen anyone else do it, but I imagine it would prevent oil spreading to where it shouldn’t.

The only issue I was worried about if that would give too little oil.

Any reason why the winding stem is oiled with HP1300 rather than 9501 or Molykote?

[VWatchie]

7 hours ago, ifibrin said:

That’s a very nice walkthrough. I might get a Miyota to practice with!

Thanks!

 

7 hours ago, ifibrin said:

I was wondering myself whether it would be better to lubricate wheels on posts by first putting the wheel on the post, then touching the Oiler with oil to the interface between the post and wheel hole. Never seen anyone else do it, but I imagine it would prevent oil spreading to where it shouldn’t.

The only issue I was worried about if that would give too little oil.

As long as I see the oil spreading around the post I have no worries. As a general rule in watch oiling "less is more", but of course, under-oiling can happen and is as bad as over-oiling.

 

7 hours ago, ifibrin said:

Any reason why the winding stem is oiled with HP1300 rather than 9501 or Molykote?

Ah, that's an interesting question which I have no definitive answer to! Anyone else? I got this practice from ETA's technical communication documents. My guess is that the synthetic HP-1300 has better longevity provided the stem has been treated with epilame, which makes the oil stay and not spread around. Or, perhaps it is just ETA in cahoots with Moebius trying to make more money (Moebius Fixodrop ES/BS 8981 epilame is expensive). I'm pretty convinced that 9501 or Molykote would work just as well. Anyway, since I have the epilame I figured, why not!?

When my 9501 expires I've been thinking to get some 9504 instead ("Composed of the basic Moebius 9501 grease and a metallic soap to get increased adhesion and consistency"). Perhaps that would be an even better option than epilame + HP-1300!?

[ifibrin]

1 hour ago, VWatchie said:

Thanks!

 

As long as I see the oil spreading around the post I have no worries. As a general rule in watch oiling "less is more", but of course, under-oiling can happen and is as bad as over-oiling.

 

Ah, that's an interesting question which I have no definitive answer to! Anyone else? I got this practice from ETA's technical communication documents. My guess is that the synthetic HP-1300 has better longevity provided the stem has been treated with epilame, which makes the oil stay and not spread around. Or, perhaps it is just ETA in cahoots with Moebius trying to make more money (Moebius Fixodrop ES/BS 8981 epilame is expensive). I'm pretty convinced that 9501 or Molykote would work just as well. Anyway, since I have the epilame I figured, why not!?

When my 9501 expires I've been thinking to get some 9504 instead ("Composed of the basic Moebius 9501 grease and a metallic soap to get increased adhesion and consistency"). Perhaps that would be an even better option than epilame + HP-1300!?

I know 9501 is supposed to be like Molykote DX, but I have always wondered how both compare to 9504. When I oil the keyless works it’s always a matter of feel whether I use HP1300 or Molykote DX, both have people advocating for their use in different parts of the keyless work.

[VWatchie]

I've never tried Molykote DX. I really don't think it makes any significant difference what you choose to use, and that the only really important thing is to apply the right amount in the right places. What I'm not too keen about is the consistency of the 9501 which can be both watery and thick. Before I use it I stir it around with an oiler. As mentioned, the next time I'll try some 9504 instead.

[ifibrin]

10 minutes ago, VWatchie said:

I've never tried Molykote DX. I really don't think it makes any significant difference what you choose to use, and that the only really important thing is to apply the right amount in the right places. What I'm not too keen about is the consistency of the 9501 which can be both watery and thick. Before I use it I stir it around with an oiler. As mentioned, the next time I'll try some 9504 instead.

That’s interesting. I’ve never had 9501 before, so this is the first time I’ve heard it described as a semi-liquid: both watery and thick. Molykote DX has a very smooth consistency like a cream or ointment for moisturizing your skin. Molykote DX is also very cheap, compared to 9501 or 9504.

[VWatchie]

10 hours ago, ifibrin said:

Molykote DX has a very smooth consistency like a cream or ointment for moisturizing your skin.

That sounds exactly what I'm looking for. Thanks for the tip! In the Watchfix.com courses Mark mentions Molykote DX as an inexpensive but good alternative, but he doesn't go into any details.

[Endeavor]

Another masterpiece   Very well done !!

[LittleWatchShop]

How is the spiral shock spring removed? 

[VWatchie]

On 12/22/2021 at 2:15 PM, LittleWatchShop said:

How is the spiral shock spring removed? 

Simply with a piece of Rodico.