My First 400 Day Clock Service

[imk]

I have been given a Kern & Sohne Bentima 400 Day clcok that look exactly like the one in the below link:

Anniversary clock - Kern & Sohne - Brass, Gilt, Glass - Second half 20th century

1970's German Kern & Sohne Bentima 400 day anniversary clock with gilt finish, hand-painted dial and glass dome. Great visual condition. Some tarnishing; few green marks to metal. I don't know if the clock works, but all the pieces seem to be present, apart from the key. 23 cm tall with dome...

www.catawiki.com

When I received it the main spring was almost fully wound but the clock didn't run, so I gave it the extra quarter turn and it ran for a few days then stopped.
I gave it another quarter turn and same again, so I have fully released the main spring and have given it a couple of turns and it seems to be running ok.

Hence, as it has stood for years in a loft I think the main spring has glued up and the clock basically needs a good service.
So question what oil's to use on this type of clock please?

Many thanks in advance IMK

 

[KurtinSA]

Welcome, IMK! Lots of thoughts on this, but generally you should try to find a synthetic oil and one of low viscosity. A good place to start is say Mobil1 0W5 or the like. Not sure what you have over there. The spring will need a good clean to get all of the old oil and varnish off of it. Then oil just a bit...you don't want to soak it in oil as that creates its own set of problems. You will need a main spring winding tool in order to easily and safely get the spring in/out of the barrel.

Let us know what you find when you get the spring out!

Kurt

 

[imk]

Hello Kurt and many thanks for the reply.
I had a look at couple of videos re removing main spring and spring winding jig etc.
It doesn't look rocket science and I think i can use the key harbor in my lathe operated by hand.
Then fashion something to hold other end of spring while winding it.

As far as Mobil 1 0W5 is concerned I couldn't find any reference to it on the web either in UK or USA.
Hence I'll have a hunt for an alternative low viscosity synthetic oils
Many thanks imk

 

[Dells]

Hello Kurt and many thanks for the reply.
I had a look at couple of videos re removing main spring and spring winding jig etc.
It doesn't look rocket science and I think i can use the key harbor in my lathe operated by hand.
Then fashion something to hold other end of spring while winding it.

As far as Mobil 1 0W5 is concerned I couldn't find any reference to it on the web either in UK or USA.
Hence I'll have a hunt for an alternative low viscosity synthetic oils
Many thanks imk

Hi imk
I am in UK and I use Mobil 1 0W5 only because it’s what I use in my car so what ever you use in your car and as long as it’s fully synthetic and low viscosity it will be fine.
Dell