This Japy clock, from about 1890, was in very poor condition mechanically because of a badly rusted escapement platform. The mechanism, except for a small amount of surface rust and tarnished brass, appeared to be in good condition otherwise. It showed very little wear but a lot of repair work, not a good sign. The platform was in bad shape, with a lot of rust on the regulator, the balance wheel and the hairspring. What I went through to repair this clock became one of my most interesting repairs in years, and I decided to write an essay about it for the benefit of other horologists.
The mechanism appeared poorly, so I decided to use photos from other clocks in this explanation. This Japy clock had the same rack and snail strike mechanism as my other Japy, from which I present this photo.
The English Lever platform was in very poor condition and with a lot of rust, so I am presenting some photos from my carriage clock for my explanation in this essay.
To determine the extent to which the platform was damaged, I removed the balance wheel and removed some rust between the pallet bridge and the balance wheel to create some clearance. Despite the rust on the hairspring, the clock ran, albeit poorly. Since English Levers often perform poorly, it was time for an experiment. I removed the platform and placed another platform in its place. I am familiar with the Russian platform with the Swiss Lever escapement, having used one on a French carriage clock. Here is a photo of a Russian platform.
This is when the investigation became interesting: the amplitude of oscillation of the balance wheels on both platforms was more or less equal