Threadlock Loose Rotor?

[firebynight]

I have a rotor that keeps coming loose, no matter how tight I screw it in. Why would it do that?

Would it be really bad form to use a tiny bit of weak threadlock such as Loctite 222MS to secure the rotor so it stops loosening? It's super frustrating!

Thanks!

[Nucejoe]

Rotors are made in various shapes, some calibers might develope such culprit, disclosing the caliber of your watch is always useful. In general,  imbalance oscilatting weight, poor thread on rotor screw or barrel arbour might cause this.

 

[HSL]

The screw might come loose if the bearing is bad, the screw mostly is attached on the top of the automatic winding mechanism, not the barrel arbor . The screw head is tightened onto the inner ring of the bearing which allows the oscillator to rotate the outer part of the bearing which is attached to the oscillator weight. If the balls inside the bearing isn't moving then the inner part of the bearing might move too and slow but sure loosen your screw. 
If you used the wrong screw, slightly to wide it will case the same effect.

[CaptCalvin]

Thread lock may be acceptable industry practice. Was taking the rotor off of a Tudor Blackbay 58. Screw was was not budging until something gave and it unscrewed the rest of the way without resistance. I looked down the screw hole with a microscope and found a whole bunch of translucent semi-circular chunks of residue had fallen bellow onto the fourth wheel jewel. This isn't the first case I've seen either.

Edited September 6, 2020 by CaptCalvin

[Nucejoe]

Advice might turn irrelevent when we don't know the caliber.

If rotor and its module (attached) can be taken out together, I use epoxy 5 as I konw it will disolve in acetone so leaves unscrewing again possible, otherwise put the glue on screwhead so it be reachable and scraped off again.

 

[Tudor]

As mentioned, if the threads seem sound, a tiny drop of purple would be fine. Apply with an Oiler to avoid fouling the bearing. 
 

It also is dissolved by acetone, but can also be released with the tip of a soldering iron on the screw, thought it usually isn’t necessary. 
 

Intetesting that Tudor not only used thread locker, but that they used too much!

[firebynight]

Apologies, the movement in question is the Seiko NH35A. Does that ring any bells?

@Nucejoe @Tudor When you say to apply a tiny amount on the screw head, you mean after I've screwed it back into the movement, right? Just right on top?

[VWatchie]

3 hours ago, Tudor said:

Intetesting that Tudor not only used thread locker, but that they used too much!

I'm not sure that's how @CaptCalvin's post should be understood!?  Someone else may have glued it down, I guess!?

[VWatchie]

3 hours ago, Tudor said:

a tiny drop of purple

What is "purple", except the colour of course?

[VWatchie]

42 minutes ago, firebynight said:

Apologies, the movement in question is the Seiko NH35A. Does that ring any bells?

@Nucejoe @Tudor When you say to apply a tiny amount on the screw head, you mean after I've screwed it back into the movement, right? Just right on top?

Nevertheless, having read @HSL's post I'd try to find a replacement bearing or complete oscillating weight. I had a look at CousinsUK.com with no luck but they may still be able to source it for you on request.

[Nucejoe]

Ya I use anything that I can dislove in chemicals, so the rotor can be unscrewed again. 

Seiko 7009 rotors kept coming loose, runs in the family.

Good luck.

[Tudor]

Purple locktite. Labeled “low strength” for small screws. I don’t remember the number. 
 

I use it all the time for case tubes, stems in crowns and carburetor adjustment screws. 
 

And it is applied to the male thread with the Oiler. Just enough to see color around the screw. If it’s “bulging” off the threads it’s too much. 
 

In the case of case tubes, it helps a lot with sealing. I’m a bit more generous with it there. 
 

I got a small bottle (special order from my local industrial supply) and it’ll last me four and a half lifetimes. 

Edited September 8, 2020 by Tudor

[jdm]

Loctite 222 - purple, it's really weak.

If a Seiko rotor come lose either one is using the wrong driver, or not tighening correctly. No locking agent is normally needed there. 

[CaptCalvin]

21 hours ago, VWatchie said:

I'm not sure that's how @CaptCalvin's post should be understood!?  Someone else may have glued it down, I guess!?

It was bought new from AD. He wanted me to do some regulation on it. Attempt was aborted when we realized the design restricted easy access to timing screws and the job cannot be done in the hour or so he was willing to part with the watch. Luckily none of the chunks landed in the jewel cup and were pick up carefully without disturbing the lubrication.

Edited September 8, 2020 by CaptCalvin

[VWatchie]

2 hours ago, CaptCalvin said:

It was bought new from AD.

2 hours ago, CaptCalvin said:

we realized the design restricted easy access to timing screws

Apologies for being OT, but just a quick question. So a Tudor cal. MT5602, w/o a regulator arm but instead four screws on the balance wheel to do the regulating? Thanks!

 

[CaptCalvin]

1 hour ago, VWatchie said:

Apologies for being OT, but just a quick question. So a Tudor cal. MT5602, w/o a regulator arm but instead four screws on the balance wheel to do the regulating? Thanks!

 

Not sure what the caliber number was, heard that Tudor has a movement made specifically for 58, but looked very similar to the pics and yes had the same type of balance setup. Screws were crosshead/Philip's style and as you can see very difficult to access in-situ with the tools I have. I either have to take the movement out of the case or take out the balance, non of which I was comfortable with doing to a brand new watch unless I had the whole afternoon.

To be fair rates in all positions were within specification. He just wanted to see if I can't make it even more accurate.

If the concern is whether or not it was fake/tampered, I can assure you, it was bought new straight from AD and had no signs of tamper. So Tudor has used thread lock, which I don't have too much of an issue with from an end user perspective. That threadlock would've stayed put until the next service had we not been naughty and tried to take the rotor off before then.

From a watch tinkerers perspective though it is a bit annoying.

Edited September 8, 2020 by CaptCalvin

[CaptCalvin]

@VWatchie Totally forgot I had taken pictures. Here they are if you're interested. Can see it's a different movement from the one you mentioned. It's marked MT5402.

And here's a microscope shot of the threadlock fragments on the jewel. A miracle none of it landed in the lubrication.

Edited September 8, 2020 by CaptCalvin

[firebynight]

On 9/8/2020 at 4:48 AM, jdm said:

Loctite 222 - purple, it's really weak.

If a Seiko rotor come lose either one is using the wrong driver, or not tighening correctly. No locking agent is normally needed there. 

Any tips about what the right driver should be? Or how do I know how to tighten correctly?

[jdm]

1 hour ago, firebynight said:

Any tips about what the right driver should be? Or how do I know how to tighten correctly?

One wide enough and with the tip shaped so it won't slip. As long only fingers on the shaft are used there is no danger of damage to the relatively large thread.

Edited September 9, 2020 by jdm

[firebynight]

Just to be sure before I apply the thread lock, which is the best spot? 

The groove for the rotor is so wide and shallow. Is there a special screwdriver for rotors? My widest watch screwdriver is 2mm ...

 

[Tudor]

I vote number three. 
 

Use an Oiler and apply just enough to make one complete revolution. If it’s bulging proud of the thread major diameter, blot some off. 
 

Too much and you will have a big mess. “Just a dab’ll do ya”