• Upcoming updates
    Over the next couple of weeks we will be performing software updates on the forum. These will be completed in small steps as we upgrade individual software addons. You might occasionally see a maintenance message that will last a few minutes at most.

    If we anticipate an update will take more than a few minutes, we'll put up a notice with estimated time.

    Thank you!

Complete service to a Hermle but it is losing power and running too fast

stephan135

Registered User
Oct 21, 2021
9
0
1
33
Country
Hello. I am working on a Hermle 340-020 movement.

I disassembled the whole movement, did some bushing work, cleaned and oiled it, but it's running too fast. Like 10 minutes every 4 hours.

The floating balance wheel is barely turning so I believe it is losing power, since it is only turning between 100 and 120 degrees.

I already tried to change and split the mainsprings and it still works bad. I also tried to test the floating balance wheel in another hermle movement and now it turns more than 360 degrees, so I don't think there is a problem in the mainsprings and the floating balance wheel.

It is hermle movement from 1978. I am not sure what else can be done since I already tried to service the whole movement.

I am attaching two pictures of how the movement looks like and a video where it can be seen that the floating balance wheel barely turns.

Video:

WhatsApp Image 2022-09-30 at 5.30.38 PM.jpeg
WhatsApp Image 2022-09-30 at 5.30.33 PM.jpeg
 

Willie X

Registered User
Feb 9, 2008
18,022
3,490
113
Looks like that one has seen a lot of action ...

You could try this: let the main springs down, removing the balance assembly and pallet arbor, then add power one click at a time to the going train. At about the 3rd click the escape wheel should turn slow and steady for several minutes. If this doesn't happen, you will have to find the problem/s in the gear train. Willie X
 
  • Like
Reactions: Jeff T and wow

wow

NAWCC Member
Jun 24, 2008
6,979
1,240
113
77
Pineville, La. (central La.)
Country
Region
The floating balance should be cleaned well and not oiled at all. I clean them with naptha followed by denatured alcohol. Once clean, the balance should rotate about two minutes on its own if mounted in a vice. The barrels and caps often need bushing. If they are sloppy and the barrel slants, power is lost. You may also have a too tight bushing causing loss of power. These movements are unforgiving and must have full power in each train to operate well.
 

Forum statistics

Threads
178,995
Messages
1,570,046
Members
54,043
Latest member
nrizzo
Encyclopedia Pages
909
Total wiki contributions
3,088
Last edit
Swiss Fake by Kent