Jump to content

Recommended Posts

Posted

I bought a Benrus DN21 movement as one of my first to practice on. I have attached an image of the movement.

From what I can find out, it is an ETA 1280 or 1281. The main plate has the ETA mark, but no calibre number.

The movement arrived with the crown/stem stuck fast. The dial had some staining, so I assumed there would be some rust in the keyless works.

As I disassembled the movement, everything looked clean and undamaged, but the stem was held fast in the main plate.

After I stripped the movement, I managed to extract the stem. I had assumed the stem had rusted and wedged itself in the main plate, but the stem didn't look as I expected. I've attached an image. What confused me was the black section by the thread.  Does anybody know what it is? Is it a collar to prevent water ingress?

I've tried to find a technical reference to see if I could identify it, but I'm having difficulty.

I'm hoping that I can just get a replacement stem and everything will be good.

Any thoughts or suggestions about this would be welcome.

Thanks
Robin

 

S20211230_0022.jpg

benrus_dn21.jpg

Posted
1 hour ago, Rhobin said:

the stem didn't look as I expected. I've attached an image. What confused me was the black section by the thread.  Does anybody know what it is? Is it a collar to prevent water ingress?

Maybe a poor quality stem that had been replaced or cobbled up? I would start checking well the bore in the plate and getting a new stem.

  • Thanks 1
Posted

Hi Have a google at Ranfft  benrus DN 21, you will find out its the ETA 1281  and it quotes the stem as W2120. I have been unable as yet to find any tech sheet for it but Ranfft has quite a bit of info .     The site  windingstems.com is another source to be explored.. There is of course the possibility of attaching an extender to the stem and re using.

Posted

Hi Had a close look at the picture.  I should check to see if there is a stem tube fitted to this watch as this looks like its rusted to the stem and come out with the stem attached,  soak the stem in coke for awhile to dissolve the rust and see if it loosens up and comes free from the stem. or it maybe a sleeve from a cobbled job as per jdm.

  • Thanks 1
Posted
7 hours ago, watchweasol said:

Hi Have a google at Ranfft  benrus DN 21, you will find out its the ETA 1281  and it quotes the stem as W2120. I have been unable as yet to find any tech sheet for it but Ranfft has quite a bit of info .     The site  windingstems.com is another source to be explored.. There is of course the possibility of attaching an extender to the stem and re using.

Thanks. I had found the Ranfft reference, but I couldn't find any reference to W2120 - probably due my lack of knowledge than availability.

I've found some stems for the ETA 1280/81 on ebay, so I was planning to order one of those.  I hadn't heard about windingstems, so I'll check that out. Thanks!

Posted
56 minutes ago, watchweasol said:

Hi Had a close look at the picture.  I should check to see if there is a stem tube fitted to this watch as this looks like its rusted to the stem and come out with the stem attached,  soak the stem in coke for awhile to dissolve the rust and see if it loosens up and comes free from the stem. or it maybe a sleeve from a cobbled job as per jdm.

I don't have the case for this watch. It was just a movement I bought for cheap that was sold for parts/repairs that I got to help learn.

I'll give the coke a try and see what happens. Thanks.

  • Recently Browsing

    • No registered users viewing this page.
  • Topics

  • Posts

    • Thanks for this post MikePilk, I just came across a similar problem with an Omega 1022.  The problem I had was the seconds pinion spring was bent out of shape and did not even engage with the wheel properly, so the seconds hand was not moving at all. (no power loss though :) I removed the automatic module so I could access the spring and work on it. Once I bent it back close to the right shape, I experienced the same problem you reported about power loss.  Many tweaks later, and the seconds hand is moving properly again, with amplitude back to good numbers again. Cheers
    • After cleaning up the pivots, I made bushes on the lathe. At this point I've pressed in 6 bushes (3 sets) and the wheels turn smooth. What I can also tell you, is that I'm not looking forward to final assembly. Getting the pivots aligned seems to get exponentially more difficult with each wheel that is added.
    • Islands are interesting places to live depending upon their size and other factors. This is a bigger island and it has a bridge to get there at least on one end. It's also big enough that you don't have to go someplace else to get things typically. It can be a problem if you get a job in Seattle though. Yes I've known of people who commuted from the island to Seattle for a job and I don't quite remember how many hours it took but it took a long time. So basically islands are nice if you don't have to leave very often.
    • Thanks @JohnR725! Everything you say makes a lot of sense and is encouraging to read.
    • isn't it nice to have a decent case open or when the case doesn't want to be opened? In the case of a Rolex watch that supposed to pass specific water resistant testing you probably do need to tighten the back down. But they shouldn't be tightened so much that they risk stripping the threads out. Then the other problem that comes up is the gaskets can start to disintegrate and then getting the back off can be quite a challenge unless you have a really good tool and perhaps some penetrating oil to loosen things up. Yes really nice case marking. When I was in school we were taught to mark the cases and  the American watch and clockmakers Institute even had a? So if you joined at one time they would give you an identification number. They were explaining or giving an example of if the watches ever found in you have a unique number they can perhaps figure out the history of the watch or identify the body it's attached to for instance not that that probably comes up that often. So you got a unique number and even made a special metal stamp that you can purchase. It wasn't a super big aggressive stamp but still it left a mark in the back of the case. Then I heard from people at work on Rolex watches they were using a felt pen indelible but later on they decided that was bad because apparently the ink could release  chemicals although it seems like once it's dry that shouldn't be an issue. Then of course today was nice is you can keep computer records sealed have to mark anything at all I personally find it's best to leave no reference behind that you were even there. Especially when you have a beautiful watch that has no markings at all and now it has your scribbling all over it not good typically if there is a typical and watch repair?  a lot of minor repairs you don't need to do a complete servicing. But beyond a certain point you're going to have to take apart a lot of stuff you're going to disrupt the lubrication even if it looks perfect right now and yes you might as well just go ahead the service the whole thing. also in a watch like this where a lot of things seem to be going on the complete service would be better then you'll know exactly where you stand versus dealing with unknown mysteries for prior repair.
×
×
  • Create New...