Mido Oceanstar screw caseback

[Hirst]

Hello wrt forum,

I have a maybe 80’s automatic mido ocean star.  I bought this as a project.  I haven’t encountered this type of screw back.  There are no flats or indents for tool to grab.  Just a round back with hardly a gap.  I tried the sticky ball but no luck so far.  Has anyone encountered this type of back on a Mido.  Is there a special tool I need to have.  Any suggestions would be helpful.

Thanks

[jdm]

4 hours ago, Hirst said:

I haven’t encountered this type of screw back.  There are no flats or indents for tool to grab.  Just a round back with hardly a gap.

If there are no points or ridges to grab on, then it's not a screw back. 

However, for this and most other questions you need to post clear pictures taken from multiple angles.

[JohnR725]

pictures would've been helpful but you still would've had problems following the standard procedure. As suggested above the back definitely does not come off. This watch goes out through the front the crystal comes off. then standard procedure to remove the crown on a frontloading watches is typically it's pulled out really hard it just pops apart.

the problem with the standard procedure is it isn't universal for all frontloading watches. My familiarity with this particular watch was another watchmaker in the shop followed the standard procedure and had a problem. One of the photographs is missing as I don't have a really good picture when he figured out he couldn't pop the crown back in again he tried to tighten the end of the stem and one side of it broke off.

the preferred method of disassembling something like this is to slide the movement out the two pieces of the stem will slide apart.

even though this was the other watchmakers problem it became my problem because I am really good at finding spare parts. This one was challenging took almost a year for a variety of miscellaneous problems. In order to get a crown we had to find eventually a case on eBay that came with its crown. That's because you can't buy this crown all by itself at least I didn't find it. Then the stems they come in a variety of lengths none of which seem to correspond to lengths that we had? The reason for the different lengths is as a guess this watch goes in other frontloading cases that require a different  Length. I think what I finally did was buy a whole bunch of them from several different sources just to find one that worked.

the problem with frontloading watches is you can't always see whether it's the standard pop apart crown or it slides apart she is want to be careful.

[Hirst]

Hello John, 

thank you for the detailed reply.  This looks almost exactly what I have but no inscription of vacuum on the back,  Just Mido Ocean star.  The stem is off this one but I can see the split inside the case as in your image.  I can wind the movement from the split.  How would one remove the crystal and then movement.  There just doesn’t see anywhere to grab.  crystal insertion tool?  It’s acrylic.  I did inspect the back today under magnification and there is definitely a seam were a screw back should come off.  Just the seam looks incredibly tight.  When ans if I can remove the crystal, then is the movement just held in by the crystal?

Thanks

[JohnR725]

1 hour ago, Hirst said:

Mido Ocean star

being curious I googled  and oceans star appears to be a very common name they had which means it could be any kind of case  etc.

1 hour ago, Hirst said:

The stem is off this one but I can see the split inside

then this definitely indicates that it's a split stem  which means it probably still goes out through the front..

But if you look at the picture of your back to the lettering is perfectly centered if it was a screw back  that doesn't always happen. although in your picture  it does look like there's a notch at 12 o'clock position and either at the nine or 3 o'clock position but normally for screw off back said be a little more pronounced?

I did find an example of a watch similar to if not the same as what I was talking about.  Even has the same movement I believe  from memory.

https://chronotimepieces.com/shop/vintage-watches/mido-ocean-star-powerwind-automatic-with-cal-917p/

then your pictures don't really show the crystal the way we need to see it. Looking straight down it almost looks flat..this is the kind the tool you would use to normally remove the crystal like this

https://www.esslinger.com/watch-crystal-remover-and-inserter-crystal-lift-tool/

the other way to tell if it goes out the front versus the back is the look at the size of the dial  and if even if you took the back off would the dial fit through the opening in the back? Otherwise it still has to go through the front side worst-case is another way to get the crystal off but it be better if you could use crystal tool above.

[HectorLooi]

If the crystal is flat, the crystal lift won't work. Then the only way is to pop it off using air pressure. This is usually done by filling a large syringe with air and forcing it through the pendant tube. But in your second photo, it looks like your pendant tube is either missing or broken. 

Another method I've heard of is to use a suction disk to pull the crystal off. Or even stick something to use as a handle on the glass using hot melt glue.

[Hirst]

Hello John, 

thank you for the detailed reply.  This looks almost exactly what I have but no inscription of vacuum on the back,  Just Mido Ocean star.  The stem is off this one but I can see the split inside the case as in your image.  I can wind the movement from the split.  How would one remove the crystal and then movement.  There just doesn’t see anywhere to grab.  crystal insertion tool?  It’s acrylic.  I did inspect the back today under magnification and there is definitely a seam were a screw back should come off.  Just the seam looks incredibly tight.  When ans if I can remove the crystal, then is the movement just held in by the crystal?

Thanks

[Hirst]

Hello Gent,

All this all these observation are helpful.  You are some observant folks.  The crystal defiantly has a wall allowing gripping.  In addition the face is too large to pass thru the back.  So this is definitely a through the front removal.  I believe the pendant tube is broken off.  Detents you observed are not original.  Now I have a direction. Get the crystal removal tool,  a new crystal, and see what else I can learn.  I’m sure there will be more surprises.

Thanks

[Hirst]

Hello Watch repair posters.  I'll add this post as a follow up.  I'm new to this hobby and having quite a bit of fun and gaining some skill while encountering plenty of challenges.  So I've completed my work on this Mido pictured in my earlier post.  I purchased it with a few issues.  No crown,  a broken off pendant tube. cracked crystal, oxidized face and bent second hands.  I have managed to attach a similar 'Mido' crown.  I have completely disassembled this auto winder, cleaned reassembled and lubricated to the best of my know how.  With a new strap, it's my new daily wear.  Keeps great time.  This is my fifth watch project.  I'm currently working on three different ladies automating watches.  Wow are these  movements tiny.  My problem now must be a common one. Too many watches to fix.  I better quit ebay !