Longines pocket watch from 1932 with caliber 18.90ZABC - Helicopters, pocket watches, flight simulation, tools.

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Longines pocket watch from 1932 with caliber 18.90ZABC

Timepieces > Longines
July 2012, this Longines pocket watch is in for a cleaning and a new glass.

I sent an email to Longines and asked for information about the watch and I got a super fast answer:

"Following your request, I have the pleasure to give you here below the information I found in our old hand-written registers :
Serial number 5064231 identifies a hunter pocket watch in Gold.
It is fitted with a Longines manufacture caliber 18.90Z that was first produced in 1928.
The "ABC" after the caliber means that your caliber is thinner than the normal one.
It was invoiced to Messrs.’ Terrasse, who was for many years our agent for Sweden, on the 31.03.1932."

NB on the case is the initials of Nils Bohn, the original owner of the watch.

August 2012, the only extra thing which needs to be exchanged is the mainspring. It should be no problem to find a new one.

In December 2012, I exchanged the spring according to the measurements of the old one, but the power reserve is only 12 hours. This can not be right. I need to investigate.

I wrote an email to Longines and I got the answer:

"For your information, the measurements for the mainspring of the 18.90Z’s caliber are :
thickness: 0.18mm
hight: 2 mm
length: 500 mm
development: 6 turns
So it gives you between 30 and 40 hours of power reserve. It depends on the use of the watch."

The maximum hight possible in the spring barrel is 1,7 mm!

February 2013, after a long time, waiting after ordering the spring from Flume I got the message that the spring is no longer available.
So the search starts all over again.

June 2013, I got a spring from Boley, 1,5 x 0,175 x 14,5, 530 mm an the power reserve is now 41 hours, perfect. The watch is back to the owner.


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