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