Okay, but what actually creates the resistance to the stem being pulled out of the case in the setting position - the post on the setting lever that snaps into the setting jumper; the post on the setting lever that abuts the walls of the stem; and/or something in addition?

 

Look at the first photo I posted. The post on the setting lever that is in the slot of the stem is the only thing that keeps the stem in place.

 

I have no idea if this is either accurate, representative of typical watches, or if I’ve misconstrued what they’re saying, but at about 1:09, it looks like there may be two posts on the setting lever, one in the stem, as you noted, and one that snaps into what they call the second position on the setting jumper. From the photo, it would look like both posts would contribute resistance to the stem being pulled out by their contact with the abutting metal.

 

Your language is somewhat vague. What do you mean by "pulled out"? If this refers to the stem being removed from the movement, then the only thing that keeps it in place is the post on the setting lever as I illustrated in the very first photo I posted.

If you are referring to pulling the stem from the winding to the setting position, then again I've already listed the things that contribute to the forces required, in my first post:

"The geometry of the setting parts and how they move (the leverage available) the strength of the yoke spring and of the setting lever jumper, and state of the lubrication in this area will all have more impact on the forces required that the crown will."

 

In the video, starting at around 1:09, they repeatedly show the setting lever movement going back and forth between the winding, and setting positions. So when I refer to, “what prevents it from being pulled out,” I mean, in the setting position, if one were to further pull on the crown, what prevents it from getting pulled out of the case?

 

I'll say it one more time...

"If this refers to the stem being removed from the movement, then the only thing that keeps it in place is the post on the setting lever as I illustrated in the very first photo I posted."

 

I had some difficulty understanding Archer's diagram, due solely to my unfamiliarity with how the mechanism works, and I believe I've parsed it, and took the liberty of annotating the diagram in the hopes of confirming my understanding and in the possibility that it would help others. Of course, all errors here and the clumsy lack of precision in terminology are mine

Here, pulling the crown and stem out one position lead to four parts moving, which I've outlined in four colors. In each case, I've outlined it with a solid line, and then again with a dotted line where I believe it will travel to when the crown is pulled out:



The blue outlined setting lever rotates around its pivot (shiny round spot at the "elbow") and the "heel" pushes against the yoke outlined in yellow, which pivots around the post at the top of the yoke in this image. That then compresses the spring (outlined in green), which gives the resistant force which requires you to pull the crown. You can see that when the crown is out, the contact point between the setting lever and the yoke is past the point of the "heel", so now the spring acts to keep the crown out and it will take force to push it back in.

You will see that the arm of the yoke interacts with a gear outlined in pink which slides along the length of the stem (see Archer's photo where the stem has a smooth square section). When the crown is pulled and the yoke rotates counter-clockwise, the gear is pushed to the left and the teeth at its end engage with the gear immediately to the left of the stem and crown assembly. The yoke sits in a shoulder in this gear so it will travel in and out as the yoke is moved in response to the setting lever.

 

Or you could just look at these two photos...

Winding position:



Setting position:



This is a 6498, so the layout is slightly different than on the 6497 (mirrored), and of course the setting lever jumper is installed here...

 

Thanks for doing that. I’m going to study it and see if I can understand it all.

 

Okay, then I am clearly missing a concept here, because in these two photos, which are very helpful, by the way, it looks as though the setting lever has two posts, both of which have abutments that would contribute to preventing the stem from being pulled out any further than the setting position.

 

Again you say "being pulled out" but do not define what that means. You can clearly see that there is only one point of contact between the setting lever and the stem in both these photos:




So once again, if you are referring to the stem being removed completely, it is just the post I've shown at the arrows.

 

Yes, I can see that directly, the point of contact arrowed does prevent the stem from being pulled out. But, via rotation on the pivot on the setting lever, is not some of the force transmitted through, and ultimately absorbed to some degree by the interface of the upper post on the setting lever and the setting jumper?

Or, put differently: if we totally remove the setting jumper from the above set up, does the setting lever move if the crown is pulled on? If not, then I see your point.

 

Good - glad this is clear.

This is about forces, and again I've stated in my first post what contributes to the amount of force needed to move from the winding to the setting position - posted again:

"The geometry of the setting parts and how they move (the leverage available) the strength of the yoke spring and of the setting lever jumper, and state of the lubrication in this area will all have more impact on the forces required that the crown will."

I don't know what you mean by forces being "absorbed" so I think you are muddying the waters here with all this. Of course for every force there is an equal and opposite reaction force, so when you pull you are pulling against something. If we are again referring to when the stem is in the setting position (not sure as you didn't specify), the forces that are from you pulling are applied to the small post I've highlighted. The force that is applied to that post is mostly carried by the pivot point of the setting lever, which is the setting lever screw.

Could the setting lever rotate more if all these other parts were not there? Sure, but then again your watch would be partially disassembled, and I'm assuming that is not a condition we are in based on the posts you've made in this thread...

 

I’m apparently not being clear, or not understanding. Thanks for your patience.

 

If you have time ...

Since people are often starting posts to ask how to remove the stem, this would be a great opportunity to show how the setting lever screw (detent) works to release the stem.

 

@M'Bob
From the pics above I guess that if you remove the jumper, then nothing prevents the lever to continue to rotate and free the stem. At least, I cannot see anything preventing that rotation to continue if the jumper is removed.
Now, the movement is uncased and the case would surely block the rotation. And with other calibers, such as in the 6497 shown in Archer's 1st post, the plate itself will prevent it to rotate

 

My physics may very well be rusty, but from the photos Al provided, it would appear that in the setting OR winding position, pulling the stem away from the case via the crown exerts almost a perpendicular force on the setting lever, looking where the pivot on it is located.

So, my uninformed thought is this: if, in the setting position, one exerts a force on the crown in an outward direction, the stem moves no further because its movement is blocked by the metal borders on the stem hitting the rigid setting lever, and, some of that rotational force is offset by the contact of the other post on the setting lever, where it meets the groove in the setting jumper.

 

Not sure this will make it any clearer but, item 2 is held with a screw from the other side. That screw is in the corner at the rotation point. Other calibres hold this part differently but here, it's a screw. As long as nothing is damaged, the screw is tight and item 2 is fitted, then you cannot remove the stem. With just item 2, the stem moves in and out with virtually no resistance. In this example, the only parts fitted are the stem and item 2 with its screw.

The gear outlined in pink is actually two parts: the winding pinion on the right which is free to rotate and the sliding pinion on the left which has a square hole so that it turns with the stem - see Al's stem picture. When you add the yoke (item 3) and its spring (in green), then trying to pull the stem away from the watch body to "time set" will clearly now have a resistance because of the reason that @TDBK gives about the heel pressing on the yoke.

But, none of this is controlled properly and for that, the setting lever jumper that Al shows is used. You can see the two notches and how it moves between the two. This adds further resistance to moving the stem in and out and limits the movement of the stem to the correct amount.

To be honest, you're overthinking this (in my opinion). I bought a new Speedmaster in 1997 and all the instructions said was to pull the crown out to set the time. As Al says, if there is a lot of resistance, you probably have an issue in the movement.

Of course, some calibres have 3 positions and these are controlled by having 3 notches in the setting lever jumper. It gets complicated...

Good luck, Chris

Of course, the winding pinion is free to rotate but, when the sliding pinion is held against it, the matching pairs of wolf's teeth means it rotates with the stem to wind the watch because the sliding pinion makes that happen.

 

On some movements the setting lever would rotate enough (again with parts removed, which wasn't in the initial question in this thread) and yes the stem will come free. But that is only because the post on the setting lever comes out of the stem. It's that post that keeps the stem in the watch.

Sure, and that setting lever jumper is held in by a screw, which requires threads in a plate, and that means you need a plate, and that plate is in a watch case, and I suppose one could continue this line of thinking all the way to the opposite hand you are holding the watch with, and all the bones and muscles in your arm...

They are all involved, but that post is the only part of any of this that touches the stem.

 

We should also explain why 2 solid collide instead of passing through each other then

About the forces and the 2 posts you are talking about, was it what you mean?

In that case yes, the 1st post prevents the stem to get out, the 2nd post prevents the lever to continue to rotate