FHF ST-96 N

[wudce]

Did not know where to post this but here. This is more of a heads up that anything else but if anyone  can help thanks. I have a FHF-96 N movement and after destroying the center wheel (I had it in my pin vise and the pin vise roll off of my table hitting my hardwood floor you can guess the rest) In looking at this https://oldswisswatches.com/watch-parts-branded/standard-st-calibre-movement-and-spare-parts/standard-st-96-n/  I see the part number as 206 so I find one and order it. After I clean it even though it was a NOS part and in it's factory sealed box and after  installing it and then the bridge I could see something is not right the pivot is not coming up far enough into the jewel. So I took it back out and look at it and the old one side by side under my microscope I can now see what the problem is. On the old one the pivot is longer and also the gear is longer which I'm not sure if that matters or not but the pivot is too short.  The box the new one came in dose say 206 so I don't know what's up or what I'm going to do next. Just though I put this out here in case someone ran into this before or may happen to them.

Edited October 24, 2023 by wudce

[Nucejoe]

 The center wheel  with longer center tube is for  variants of ST96 with date or date/day complications, as date ring takes space which increase the hight of the movement thus longer center tube. 

Rgds

[Waggy]

Maybe a little off topic, but I find buying a whole used movement from ebay often works out cheaper (in the long run) than buying an individual new part(s), depending on what it is of course. The added advantage of this is that you get the unused parts for free and can maybe use them in the future. On more than one occasion I have needed part X only to find out later in the build that I also need parts Y and Z, luckily the movement I ordered will have these parts and I don't need to return to suppliers to order the additional parts. This is especially attractive to me due to the fact that based where I live it can take two or three weeks to get the part from the supplier to my door, therefore needing one part and then another and then another.... could delay a build months.

There is a risk of course that you may end up with a movement with the part(s) you want missing or damaged, but it's usually worth the gamble in my experience.

[wudce]

Was trying to stay away from buying another movement but may have to. Still is strange what is going on why the data sheet say what it dose yet the part is not the same.

[dadistic]

It is common for center wheel heights to vary, especially with movements that are used in a variety of different watches.

It's just something that you have to be aware of, and even when ordering a new movement you should know what center wheel height you need. 

Best thing to do is to measure the height of the one you are trying to replace, and then verify the new part before ordering.

Cheers!

[Nucejoe]

23 hours ago, wudce said:

 On the old one the pivot is longer and also the gear is longer 

You say the gear is longer, do you mean the pinion is longer ?   the gear and  center tube is one piece and is called pinion ?  The new one can be replaced with the old, do you have a staking set? 

 

 

Edited October 25, 2023 by Nucejoe

[wudce]

You can clearly see from photo the new is not long enough to allow it to come up into the jewel. Not sure what can be done with a staking set but yes I have one.  

[rehajm]

38 minutes ago, wudce said:

You can clearly see from photo the new is not long enough to allow it to come up into the jewel. Not sure what can be done with a staking set but yes I have one.  

I'm having a go at making the old wheel flat if bent is the only issue...and the wheel is probably friction fit on the pinion so I suspect Nucejoe's 'the new replaced with the old' is swapping out the bent wheel for the new one on the correct sized pinion. 

Edited October 26, 2023 by rehajm

[Nucejoe]

Just as rehajm expained, 

The (  center tube &  pinion  )   is one only piece which is friction fitted onto the gear, and is removable.

 YOU CAN FIT THE LONG TUBE  ONTO THE NEW GEAR.

While you have the long tube removed, you have good access to polish its pinion leaves.

Good luck

 

 

[Nucejoe]

 Needless to say, you should measure and make sure both center tube have the same diameter.

Let us see a picture of the new gear center hole after you took its center tube off.

Rgds

[nevenbekriev]

The easiest thing to be done is to straighten and true the old original wheel. Of course, if it is just bent, with no broken spokes and no out of round.

The wheels consists of table and pinion. Table is the brass part, pinion is the part made of steel. They are riveted together. Separating them is possible, but then connecting them together is a little problematic - the hole of the table deforms, the riveted part of the pinion must be turned back by rolling on lathe, and in the end - risk of excentric coupling exists.

[wudce]

Been making some head way on trying to  straightening it but it's slow going and I know it will never be 100% right. As far as removing the parts and trying to refit them well that's well outside of my exp level