Split stem repair

[Kkwong]

Hi,

Need some advice.

I was trying to push back the split stem into the movement after replacing battery, the split stem (male side) has snapped, think I must have done it incorrectly.

Hence I bought a replacement stem (for ETA926.301) from Cousins, but I found the replacement stem is slightly different from the original one, there is a piece of round metal at the top of the male stem (pic with red circle) which is different from original one.   The round tip seems to be too thick to push into the female stem.  I don't want to repeat my mistake again ny snapping it.

Just wanna to check a correct way to fit a split stem into the movement, should I just push in with force at the right angle? Or pre-engage (slide in first) the male stem with the female stem, then push into the movement? 

Is this tip (red circle in picture) normal? or should it be filed down to fit the female stem?

Your advice is much appreciated.

Learn a lot from this forum indeed.

[Knebo]

Hi @Kkwong,

Could you clarify what the 2nd picture shows? It kinda looks like you managed to fit the new stem (with the knob) in your female crown-stem. Or what is this showing?

Cheers 

1 hour ago, Kkwong said:

 

[Kkwong]

Thanks Knebo,

The second pic is trying to show the top knob is too thick to fit in the gap in female stem, I dare not to push in yet, as I don't know the right way to install a split stem.  Again, worry to snap it again, as the male side looks too flimsy, which I snapped it when I tried to install the original one, perhaps pushed in wrong angle.

Edited July 27, 2023 by Kkwong

[Knebo]

Oh ok, on the picture it looked like it was fitted in successfully. But now I see that it's not fully in.

Tricky.

I have one watch with a split stem and I can take it off and put it in by just pulling/pushing. I hear a nice 'click' sound when I push it in. It takes some force, but not excessive. I do it when the male part of the stem is already installed in the fully closed watch, so that I can hold the watch firmly in my hand and push the female stem side on.

That being said, I don't want to suggest that you 'force' it. Because if it doesn't fit properly, it'll break.

[Kkwong]

Thanks Knebo for your experience sharing.  I think my first attempt has a wrong angle, hence snapped the original stem.

And this replacement has a knob on top which is different from the original one, so don't know if it serves any purpose.  Do you have this knob on your split stem?   Otherwise, I am thinking of filing it down to fit the female top notch. 

But only when I am sure what that knob is about.

Thanks for your advice, appreciated.

[Knebo]

I'll try check my stem tonight (I'm at the office now and it's 10am in my time zone).

I guess the question is: will the stem hold in place firmly enough without the knob (if you file it down)? 

 

 

[HectorLooi]

I don't think the breaking of your original stem was any fault of yours. Split stems have an inherent risk of breaking regardless of how carefully it's done. That's why when you undertake the task of servicing a watch with a split stem, you need to add the cost of a new stem and labour involved if it should break.

I think the little knob adds a little rigidity to the coupling. Without the knob, the joint would be a little wobbly. But I've come across some watches with the knob is missing. I think that allows the stem to be inserted into the pendant tube first and then the key slot turned to face upwards. The male part of the stem can then be turned to face in the same direction and the whole movement can be dropped into position. This reduces the number of times the female socket gets stressed and risk breakage.

[Kkwong]

Thank HectorLooi for your advice.  Split stem is really fragile indeed.  Will research more and see how it should be fitted.

Thank you all for your support.