Is it possible to repair a screw down crown?

[GuyMontag]

The crown on this Mido 8299 screw down crown seems to be broken. When I turn the crown counterclockwise the stem turns with it. When I turn it clockwise the stem does not turn with the crown. This makes it impossible to set the time backwards or use the day (date? I forget) quickset. I've tried to find a NOS one but haven't had any luck yet. Is there any way to fix this?  I thought about maybe putting a thin shim between the crown and the stem but as the stem is spring loaded I don't think that would work.

 

 

Edited November 22, 2024 by GuyMontag

[RichardHarris123]

Threadlocker ?

[GuyMontag]

To be honest, I don't even know how the stem is supposed to come out of the crown. I assume it isn't screwed in as I don't see how it could be spring loaded if it was.

 

EDIT: just to test I put the stem in a pin vise and tried to remove the crown but it doesn't want to come off.

Edited November 22, 2024 by GuyMontag

[AndyGSi]

I expect the spring has lost it's tension and isn't pushing the crown out enough to engage with the stem.

To remove the crown try gripping the crown tube and then rotate it anti clockwise.

 

Edited November 22, 2024 by AndyGSi

[GuyMontag]

I did try removing the stem with a pin vise and it doesn't want to come out. I didn't pull crazy hard. That video said that, at least in that style of screw down crown, it's glued in. Not sure if that is true, that sounds a little odd. I've seen other posts that say it's soldered in? If it's not held in mechanically and it is glue or solder, I'm worried that if I take it out I won't be able to get it back in again.

[Neverenoughwatches]

8 hours ago, AndyGSi said:

I expect the spring has lost it's tension and isn't pushing the crown out enough to engage with the stem.

To remove the crown try gripping the crown tube and then rotate it anti clockwise.

 

Marc...articulated guy with great knowledge......explains clearly enough to understand in a heatbeat what's happening. Worth watching his other tutorial videos and collaborations with Tristan Veneto.

6 hours ago, GuyMontag said:

I did try removing the stem with a pin vise and it doesn't want to come out. I didn't pull crazy hard. That video said that, at least in that style of screw down crown, it's glued in. Not sure if that is true, that sounds a little odd. I've seen other posts that say it's soldered in? If it's not held in mechanically and it is glue or solder, I'm worried that if I take it out I won't be able to get it back in again.

Its the collet that is glued/soldered to the crown. Marc did say its a permanent assembly...so unless the keywayed collet is screwed onto the crown with yours . Maybe yours isn't a keyway that locks the stem both ways and operates as a oneway latch.

[AndyGSi]

2 hours ago, Neverenoughwatches said:

Maybe yours isn't a keyway that locks the stem both ways and operates as a oneway latch.

It's got to lock both ways if it's got Day & Date Quickset.

8 hours ago, GuyMontag said:

I did try removing the stem with a pin vise and it doesn't want to come out.

Did you try holding the crown tube instead of the stem and then unscrew the crown?

[mikepilk]

I was surprised that you can repair these. I had one on a Ladies Rolex/Tudor where the spring had broken inside. I managed to change the spring and get it working. You have to grasp the centre tube very tightly in the pin vice, BUT not crush it. Watch the video.

 

 

Edited November 23, 2024 by mikepilk

[GuyMontag]

6 hours ago, AndyGSi said:

It's got to lock both ways if it's got Day & Date Quickset.

Did you try holding the crown tube instead of the stem and then unscrew the crown?

 

6 hours ago, mikepilk said:

I was surprised that you can repair these. I had one on a Ladies Rolex/Tudor where the spring had broken inside. I managed to change the spring and get it working. You have to grasp the centre tube very tightly in the pin vice, BUT not crush it. Watch the video.

 

 

Thanks all. So I did as in the video and grabbed the crown by the tube with a pin vise and cranked it tight with two pliers. I tried to remove the crown but it wouldn't budge. I then heated the crown up with a soldering iron and it still wouldn't budge. I guess this is one of the soldered type and not a screw or glued type. Unless there is something else to try I guess I'll just have to wait and see if one turns up on ebay.

[AndyGSi]

If you pull the crown while holding the stem does it move our further and can you get it to lock in both directions?

[GuyMontag]

18 minutes ago, AndyGSi said:

If you pull the crown while holding the stem does it move our further and can you get it to lock in both directions?

Good call. I had tried that before using my fingers and it still wouldn't lock in CCW. I just tried putting my smallest screwdriver blade through the hole in the split stem and pulling on the stem and I heard it "pop" and it now locks in both directions. However, it doesn't want to (easily) push back in. I used a decent amount of force and it pushed in, but it stayed compressed. I pulled it back out and and still locks, but something is clearly borked with the spring. I think I may be able to use it as is until/if I can source a replacement. Cheers

Edited November 23, 2024 by GuyMontag

[AndyGSi]

35 minutes ago, GuyMontag said:

Good call. I had tried that before using my fingers and it still wouldn't lock in CCW. I just tried putting my smallest screwdriver blade through the hole in the split stem and pulling on the stem and I heard it "pop" and it now locks in both directions. However, it doesn't want to (easily) push back in. I used a decent amount of force and it pushed in, but it stayed compressed. I pulled it back out and and still locks, but something is clearly borked with the spring. I think I may be able to use it as is until/if I can source a replacement. Cheers

Try soaking it in IPA and see if you can get any debris to come out which maybe restricting its movement.

If you've got an ultrasonic tank then put it in a little bottle of IPA and leave it to soak before putting the bottle in the tank for 10 or 15 minutes.

Edited November 23, 2024 by AndyGSi

[GuyMontag]

Thanks, I'll give that a shot.

[mikepilk]

3 minutes ago, AndyGSi said:

Try soaking it in IPA and see if you can get any debris to come out which maybe restricting its movement.

If you've got an ultrasonic tank then put it in a little bottle of IPA and leave it to soak before putting the bottle in the tank for 10 or 15 minutes.

I'd use naphtha as IPA isn't good at dissolving oil and grease.