I received this Delbana watch last week to take a look at. The condition is near mint but the watch ran irregularly, the winding and setting appeared to be sluggish and it didn’t keep correct time. The watch is 34 mm in diameter without the crown and the movement is an AS/ST 1950/51, a hand winder with 17 jewels. That would place the Delbana watch in the 1960s.
Get to work
I uncased the movement with the dial, removed the hands and then separated the dial from the movement. It became immediately clear why it didn’t operate smoothly and ran slow. To be honest, there could have been more wrong with it but this would be at least one of the reasons.
As you can see, the movement has been over oiled and it’s dripping with oil. The owner told me that he bought the watch from a shady merchant. A common practice, although a questionable one is to dunk the movement into oil just to make it run long enough to complete a sale. They don’t care what happens afterward because they only appear on fairs and they’ll be long gone before you notice there is something wrong.
I flipped the movement to the other side and started with removing the balance and the pallets. After I removed the barrel bridge, crown wheel, and ratchet wheel there was the familiar oil again!
I finished disassembly and cleaned all the parts in the vintage Elma cleaning machine. Everything has to be done manually and the timer is an old fashioned egg timer but it works beautifully. I use L&R #566 cleaner in the first bath and L&R rinsing solution #3 in the next two baths and that gives great results. After cleaning I inspected all parts but I didn’t find damage or extensive wear on any of them.
I started with the reassembly and really there is nothing unusual or out of the ordinary with this movement. The only thing to notice on the “work side” is to lubricate the 3rd wheel bearing jewel before you put the crown wheel back on.
On the dial side, remember to lubricate the friction pinion on the 3rd wheel (red arrow). I use Moebius 9501 for that but I’ve heard some good stuff about Molykote as well. Also, remember to put the minute wheel back at the correct “side” of the friction spring (green arrow). Lubricate the jewels before you reassemble the motion work.
I completed the movement and put it to a 72 hours test. Afterward, I regulated it as accurately as possible. The amplitude is still somewhat on the low side but it’s acceptable. It runs steady and with a low beat error. This smart Delbana watch is good to go again for years to come.
If you have any questions or tips or complements, please leave a comment below.