With reference to Dufourism's picture above, beat error is when the "left swing" and "right swing"

Mar 12, 2018,16:38 PM
 

i.e. when the "tick" and "tock" of a watch are of different timing lengths, they need to be adjusted so they are equal duration. This can be fixed by adjusting the position of the start of the hairspring (the stud).
A watch can be at the correct beat rate (i.e. number of beats per hour), but can still have a beat error. It matters because if your watch is in different position as you wear it, the timing may start to have variations.
Regards,
skyeriding

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Swan-Neck adjustors on Free Sprung Balances?

 
By: patrickmatthewchu : March 6th, 2018-19:36
I understand that this hairspring in the (beautiful) Zeitwerk movement is free sprung. However, I don't quite understand how this works. I know that having a free sprung balance means that the length of the hairspring is not adjustable via a regulator. Si...  

I think if it's free sprung it's for beat error adjustment

 
By: nwk00 : March 6th, 2018-19:43
Some Glashuttes have dual swan necks, one for rate and one for beat. It also looks good, otherwise the balance cock is a bit naked.

nwk00 is right.. The swan-neck regulator is for adjusting beat error..

 
By: Dufourism : March 6th, 2018-20:49
In this case, the swan-neck adjusts the neutral position of the roller jewel. Image courtesy of joel_carvajal: ...  

The diagrams and explanations above by nwk00 and Dufourism sums it up beautifully...

 
By: skyeriding : March 7th, 2018-00:30
Just to clear up/reiterate on terminology (and correct me if I'm wrong) - in the old days before freesprung balances are invented, mechanisms like the swanneck are used to finely adjust the beat rate. Hence, for non-freesprung Lange watches we refer to it... 

With reference to Dufourism's picture above, beat error is when the "left swing" and "right swing"

 
By: skyeriding : March 12th, 2018-16:38
i.e. when the "tick" and "tock" of a watch are of different timing lengths, they need to be adjusted so they are equal duration. This can be fixed by adjusting the position of the start of the hairspring (the stud). A watch can be at the correct beat rate... 

Excellent post!

 
By: patrick_y : March 7th, 2018-08:53
Thank you for sharing your technical knowledge! You're one of the reasons why PuristSPro is the wonderful place it is on the internet for technical information about watches!