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Cheers mates!!

Had to get new winding stem to an Omega cal. 342 , beacuse not original crown.

Got an replacement from Ronda, but does not fit.

Tried to fit the stem yesterday, but Im not able to get in in right in the movment.
The original just go right in every time, but the new Ronda stem will not go properly in.
Are there anyone that have some ide why this not fit?
Can the notch in the stem where I have put red arrow have somthing todo with this??
Its slightly smaller on the Ronda stem...  se photo


stem passer ikke.jpg

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That I can measure when comming home, but I get the stem almost all the way in, but when I try to screw down the screw for the setting lever, I can screw that all the way down, but the the stem will not hold in the movment, seem that it not get in grip sort of...

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The space for the setting lever is wrong on the new stem it is too wide. Are you sure, when it is screwed right down it is flush in the gap. Are you sure, there's no wear to the plates when the stem is between them. If you can wiggle the stem left to right or up and down, I would say its wear that could be why it just pulls out. Does the setting lever notch have any signs of wear? If it is the wrong stem, all sorts of problems can accrue.

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Like OH pointed out, many possibilities. 

Solutions are many as well, I recommend modifying the old stem.

1- measure the old stem, crown to stem end. 

2- Use heat( solder gun) to heat the stem near the crown. Drop in cold water. Repeat. This by itself is unlikely to let the crown unscew, soak in kerosene for a few days or pentrating oil, B12, WD 40,  The crown should unscrew. 

3- Combine the crown and a stem extender to get the best fit of the stem.

4-  you may use superglue on the section of stem on which stem extender screws.

No superglue on the crown.

Best wishes.


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Ranff lists the stem as "Stem W2907" - which is fine, if you can source one, however if like me, you are scrabbling around in a big pile of random stems trying to find one that fits, then I might be tempted to chuck up the one you have in your lathe/drill press/hand drill, and slightly increase the width of that slot with a small file.

If you have a micrometer, or a good "metric calibrated eye" you can measure/eyeball the old one, and "sneak up on it"  with the file,  as it were till the two match. Bear in mind that the slot should be in the same relative position as the original, so you may need to sneak up on it from both edges of the slot. If the slot is too small, then the relevant bit of the keyless work that drops in to it.. wont.

Edited by AndyHull

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