How do you fix a loose friction fit pendant tube ?

[mikepilk]

Never had to fix pendant tubes before, but I've got a Sekonda/Poljot 2612 with a loose tube.

The diameter measures 1.92 mm, which seems an odd size - it's not really loose, just not tight enough, it pulls out with the crown.

Is there a method to secure them (Threadlock?) or do I need a new pendant? If so what size?

The outer part diameter is 2.15 mm. I guess that gives a waterproof fit in a 2mm crown?

  

[nickelsilver]

I would use Loctite 648. It's specifically for locking cylindrical fits, basically permanent unless significant heat is applied. Clean with acetone first!

[HectorLooi]

I'm also in the process of restoring a 2612. It's a Poljot alarm watch. The seller claimed that it has been serviced by a watchmaker and is in good working condition. 

That was far from the truth. The movement was absolutely filthy. The case gasket was a strip of rubber, coiled around the rim. The crystal is not original as file marks on the edges are visible. One pendant tube was missing and the other is a crumpled brass tube. One dial foot was broken off and the ratchet wheel was warped. There are only 3 good things about this watch, which are the mainspring and alarm spring appers to be new and the price of the watch.

I thought only sellers from south Asia were capable of this but was I mistaken.

[mikepilk]

The watch I bought was being sold for parts. The case/dial/hands are OK but the movement is the oiliest/dirtiest I've come across. There's what look likes a blob of black tar sticking the hairspring together. And there's no escape wheel.

It's so dirty and oily, I'm going to give the whole movement a few minutes in the ultrasonic before I strip it.

The good news is that parts are easy to find and cheap (which I checked before buying) - On Cousins almost all parts are £5.95+VAT

 

Edited October 23, 2021 by mikepilk

[HectorLooi]

Hey! I got it's twin!

[Deomandinka]

On 10/22/2021 at 4:24 PM, mikepilk said:

Never had to fix pendant tubes before, but I've got a Sekonda/Poljot 2612 with a loose tube.

The diameter measures 1.92 mm, which seems an odd size - it's not really loose, just not tight enough, it pulls out with the crown.

Is there a method to secure them (Threadlock?) or do I need a new pendant? If so what size?

The outer part diameter is 2.15 mm. I guess that gives a waterproof fit in a 2mm crown?

  

I have had this a few times. In the past I used a wee bit of "shoe goo" to act as a seal, and then used the point of a SS conical shaped nail to expand the tube back out when it is back where it should be. I have used a vice and or plyers to push the nail in to the tube to expand it. If the tube sticks out in to the watch, I don't recommend this as it will probably split the tube. I'm not a fan of threadlock etc because it is designed to break under pressure so you can still remove the bolts if necessary. I have had also had some good success with superglue but you have to be quick and do not use gell as it seems to set quicker. You have about 4 seconds to make sure it is in the correct place. As Nicklesilver said, give it a good clean with solvent first.

[clockboy]

Loctite would be my method. Just clean the tube and case with a degreaser such as mentholated sprit before applying the loctite. 

[mikepilk]

3 hours ago, Deomandinka said:

I have had this a few times. In the past I used a wee bit of "shoe goo" to act as a seal, and then used the point of a SS conical shaped nail to expand the tube back out when it is back where it should be. I have used a vice and or plyers to push the nail in to the tube to expand it. If the tube sticks out in to the watch, I don't recommend this as it will probably split the tube. I'm not a fan of threadlock etc because it is designed to break under pressure so you can still remove the bolts if necessary. I have had also had some good success with superglue but you have to be quick and do not use gell as it seems to set quicker. You have about 4 seconds to make sure it is in the correct place. As Nicklesilver said, give it a good clean with solvent first.

What is "shoe goo"?

I've ordered some Loctite 648 - designed to be more permanent than normal thread lock. AS @nickelsilver says : "It's specifically for locking cylindrical fits, basically permanent unless significant heat is applied". 

 

[Deomandinka]

On 10/24/2021 at 2:13 PM, mikepilk said:

What is "shoe goo"?

I've ordered some Loctite 648 - designed to be more permanent than normal thread lock. AS @nickelsilver says : "It's specifically for locking cylindrical fits, basically permanent unless significant heat is applied". 

 

No Worries, I like to make sure my stuff is 100% waterproof. Shoe Goo is a semi liquid rubber used for, ironically, repairing shoes.  Good luck

[Jack75]

Was there a typo?  Loctite 638  is the gap sealant.

Loctite 638.pdf

[nickelsilver]

30 minutes ago, Jack75 said:

Was there a typo?  Loctite 638  is the gap sealant.

Loctite 638.pdf 80.91 kB · 1 download

648 is lower viscosity and for smaller gap filling; on something like a tube that has slight but insufficient friction it has a better performance than 638. For larger looser fits, or where a portion of the part can be recessed to provide room for the product 638 is a better choice.

[rodabod]

If the tube is particularly loose then I sometimes tap a punch or broach into it to spread it open very slightly. And also apply loctite.

[mikepilk]

7 hours ago, rodabod said:

If the tube is particularly loose then I sometimes tap a punch or broach into it to spread it open very slightly. And also apply loctite.

I asked the original question as I didn't know if they are just friction fit, or is it common to use Loctite. I used the Loctite 648, which seems to have done the job. I can also see that the other tube was glued in.

[rodabod]

In terms of threadlock or not: the BHI say that stem threads should now Abe threadlocked, so I’m guessing the same would apply to pendant tubes. They now advocate using it for fixing clock wheel collets too. 

[nickelsilver]

I try to always make sure stems, tubes, repivots etc. are a good mechanical fit. But I will often use a bit of appropriate Loctite as a belt and suspenders. Especially for tubes that should be press fit, but sometimes the hole has a terrible surface finish or the fit is iffy, loctite helps make sure its waterproof and not going to work out. And it can be hard to judge the fit- it might seem like it will be a good fit, but is a little loose, but the stainless on stainless wants to gall when removing...- and the Loctite actually eases the assembly a bit even if it's actually a tight fit!