BP43 crown ‘feel’

Hi all,

First time IWC/mechanical watch owner.

I’ve always loved the history and look of the BP, and pulled the trigger on a 43 recently and absolutely love it! I’m obsessed. 

A few questions about the crown and hands - potentially very ‘noob’ questions here so I apologise in advance.
 

When reading ‘how to set the time’ the manual explains to: 

“Move the minute hand a few minute strokes beyond the time to be set. The minute hand can be positioned exactly above the correct minute stroke by moving it backwards gently.” 

So, if for example I wanted to set 01:10 (second hand stopped at 12), I wind it to 01:13 or so, then wind it backwards to 01:10? There is a little bit of ‘play’ in the crown that I’ll refer to as the ‘dead zone’ where there is absolutely zero resistance and the hands don’t move. It’s probably +/-20 degrees of rotation. I can rotate it back and forth with my pinky finger and the minute/hour hands don’t move at all. When continually winding in the same direction though, the crown will ‘grab’, and I need to pinch it to rotate and actually move the hands. The pinky no longer suffices as the tension increases.

Question one - is this normal? This ‘dead zone’ in the crown? 

Next question is bit more difficult to explain, but say I’m winding from 01:00 up to 01:10 and don’t wind it backward at all (sitting on the ‘start’ of this ‘dead zone’). If I try to push the crown in, it’s extremely spongy, and doesn’t click in. But when I wind it back a small amount, through that ‘dead zone’ and through the ‘end’ of the ‘dead zone’, the hands will start moving backward a small amount. When I try to press the crown in here, it clicks in place beautifully.

So next question - Is this what IWC are trying to get at? That it won’t click back in if you wind forward and are sitting on the ‘start’ of that ‘dead zone’ which could potentially damage the watch? 
 

Next question - is it bad to push the crown in if it is in this ‘dead zone’? 

Last question - What’s going on internally here, can I damage the piece if I applied enough force (which I would never do) in the ‘dead zone’ area? 

The watch is functioning flawlessly (about +2 sec a day) and I just make sure to wind forward (about 2 mins past the intended minute) then wind it back to the minute I want and then, only then, do I push the crown back in. 

I hope this makes sense! Any info on this is greatly appreciated!! Thank you!!

Hi

What you are experiencing is the interface between the movement and the hands controlled by a part called the cannon pinion.

It can be neither too loose nor too tight or there’ll be “slop” in the hands or too much restriction, causing the hands to move inaccurately, so it’s important to get it as precise as possible.

While I don’t know why, IWC has chosen to allow some level of slippage in their design - thus the instructions they provide. It’s likely a trade off between consistent adjustability and wear and tear.  Since they have quite a history using ETA movements, they may have incorporated a similar design in their own movements. ETA has a slightly different design which all but eliminates the slippage but may result in greater wear and part replacement. By allowing a bit of slippage, they may likely avoid the wear problem. 

As for your “dead zone”, i don’t think you’re doing any damage unless you’re sensing metal-to-metal contact but if you follow their instructions you shouldn’t have a problem. 

Different companies take different approaches and IWC isn’t the only company that has this characteristic, but they’re the only one I’ve encountered that accounts for it in the instruction manual. 

Hope this helps.

Cheers!

T

 

Thanks Terry!

I appreciate your reply and for taking the time to provide some direction on this. It really is fascinating when it comes to the intricacies of mechanical watches! 
 

Thanks again

• Yes, the “dead zone” is normal. What you’re feeling is backlash/play in the keyless works and motion works. All mechanical watches have some free play when changing direction.

• IWC’s setting advice is exactly to deal with this. Going a few minutes past and then setting backwards takes up the slack so the minute hand is fully loaded against the gear train and sits precisely.

• The crown feeling spongy and not clicking in at the start of the dead zone is also normal. You’re basically mid-transition in the keyless works. When you reverse slightly and the gears re-engage, everything aligns and the crown seats cleanly.

• Pushing the crown in while in the dead zone won’t damage the watch, but it’s best practice to avoid it. Just do what you’re already doing: reverse slightly until the hands move, then push the crown in.

• Nothing dangerous is happening internally. You’d need excessive force to cause damage, and normal use won’t do that.

Glückwunsch zur BP 43 – großartige Wahl 😊 und willkommen in der Welt der mechanischen Uhren.

Zu deinen Fragen, ganz ruhig: Das, was du beschreibst, ist bei vielen hochwertigen mechanischen Werken völlig normal, auch bei IWC.

Zur „Dead Zone“ der Krone:
Ja, dieses leichte Spiel ohne Widerstand ist normal. Das kommt vom Zusammenspiel aus Zeigerstelltrieb, Kupplung und Rücklaufsicherung. In diesem Bereich wird noch kein Drehmoment auf das Zeigerwerk übertragen, daher bewegen sich die Zeiger nicht.

Zur Anleitung (vorwärts stellen, dann leicht zurück):
Du hast das korrekt verstanden. IWC empfiehlt das Zurückdrehen, um Zahnspiel (Backlash) im Zeigertrieb zu eliminieren. So liegen die Zahnräder sauber an und die Minute steht exakt dort, wo sie soll.

Warum die Krone manchmal „spongy“ wirkt:
Auch das ist normal. Wenn du am Anfang der Dead Zone bist, steht der Stellmechanismus unter keiner definierten Spannung. Erst wenn du minimal zurückdrehst und die Zahnräder wieder Kontakt haben, rastet die Krone sauber ein. Das ist kein Schutzmechanismus im engeren Sinne, sondern einfach Mechanik.

Ist es schlecht, die Krone in der Dead Zone reinzudrücken?
Nein. Solange du keine Gewalt anwendest, passiert nichts. IWC-Kronen sind robust konstruiert. Dein aktuelles Vorgehen ist aber absolut vorbildlich.

Kann man intern etwas beschädigen?
Nur mit erheblicher Gewalt – und das würdest du sofort merken. Normale Handhabung, wie du sie beschreibst, ist völlig unkritisch.

Kurz gesagt:
✔ Dein Vorgehen ist korrekt
✔ Das Verhalten ist normal
✔ Keine Sorge um das Werk (die Gangwerte sprechen für sich)

Manchmal fühlt sich Mechanik kompliziert an – ähnlich wie bei einer gründlichen endreinigung wohnung zürich: Wenn man versteht, wie es funktioniert, ist alles halb so wild 😉

Viel Freude mit der BP – sie wird dich lange begleiten.

I think it is about time to do something against these nasty BOTs. If you look at the latest 10 forum threads, I guess around 90 % of the posts are created by BOTs. The whole forum is close to being unusable. 

I am far away of being a specialist against BOT attacks but for me the forum is dead if the BOT situation cannot be improved anytime soon. Sad. 

The BP43 crown dead zone is normal play in the gears. Wind slightly past the time, then back to set hands accurately. Spongy feel and delayed click are normal. Pushing gently in the dead zone is safe. No damage occurs under normal use.