Good test for power in a movement.,,

[NEW65]

I have an hermle 0451 which I rebuilt recently. It needed a lot of work as it was very worn. 10 hours later I finally completed it! I always find it strange when for example you can have two brand new 0451’s and one chimes at a much faster rate than the other.
The used movement that I’ve just rebuilt chimes the quarters relatively slow. Naturally I thought that i had messed up with the rebuild . However I decided to test the movement out by exchanging the heavy lead filled weight with a iron filled weight and the lighter weight still operated 1x4, 2x4, 3x4, 4x4 albeit chiming very slow. I therefore have two questions;
Based on the new movements why do the rate of chimes differ so much and finally ,
if a much lighter weight can operate the chimes is that a good sign that the rebuild I did has been successfully done?
Thanks as always

 

[shutterbug]

I guess if the chimes are not slowing down during the hour chime (the longest run) all is OK. And yes, a lighter weight verifies a well running train.

 

[Bruce Alexander]

You might check for differences in hammer spring tension.
The more friction you've eliminated in a gear train, the less power is lost to it. With less waste, less power needs to be introduced to the work of the hammers at a governed rate. I would expect that the less power needed to operate the train, the slower should be the rate of wear throughout its moving parts. There is a practical limit to power reduction though. Friction will increase with time so one has to "strike" a balance between performance and resistance to wear. Taken to the other extreme, American clock manufacturers reportedly over-powered their movements to reduce warranty work. As a result, their movements ran well beyond warranty periods as well as far beyond the effective limits of clock lubricants over time

 

[NEW65]

Thanks Shutt for adding that. I suppose the longest run gives a good idea of how well the movement performs. What I find odd is that some movements including new, tend to slightly slow down as the long lever is lifted towards the end of the 4 x 4 chime. On the other hand some of the rebuilt movements do not do that and the hammers show no sign of slowing down.

 

[NEW65]

Taken to the other extreme, American clock manufacturers reportedly over-powered their movements to reduce warranty work. As a result, their movements ran well beyond warranty periods as well as far beyond the effective limits of clock lubricants over time

Thanks Bruce for your reply, interesting read.
You mention over powering movements which means using an heavier weight than recommended to drive the train. Yes I suppose this would overcome issues caused by friction and would exceed the guarantee period. I guess however that the movement would wear out much more quickly, caused probably by the extra weight prematurely elongating the pivot holes.
Cheers Bruce