How to get the galloping horse out of my clock??

[Endeavor]

Hello All;

I'm working on a 8-days movement of a Soviet Vostok U-boat clock.

I bought it as being defect, and indeed it had a broken balance-staff pivot, a knocked-down pallet-fork jewel failing to lock the escape-wheel, a broken pivot of the bottom escape-wheel pinion and some damage to the tops of the Contrate-wheel teeth. I was the "first-in" after the clock left the factory.

A complete NOS escapement platform was ordered and while waiting, the clock was disassembled, cleaned, re-assembled and oiled with Dr.Tillwich 859 clock oil. The Contrate-wheel repaired and the main-spring barrel, with a Geneva-stop was left untouched and it looked clean and was still oiled.

The NOS escapement platform was disassembled, cleaned, the balance poised, the Breguet hairspring adjusted, re-assembled and oiled (including the pallet-jewels) with Dr.Tillwich 3-5, which is about equivalent to Moebius 9010.

Platform installed and adjusted to correct engagement depth.

The unknown lift-angle was established at 52-53 degrees.

With a few clicks on the, due to the Geneva-stop pre-tentioned mainspring, the amplitude was already around the 250-260 degrees.

Here my setup with the clock movement and the timegrapher.

Here the amplitude with "minimum"-mainspring tension.

 

When winding the main-spring, close to 1/2 way of the Geneva-stop, the amplitude has increased already so much so that the escapement starts over-banking, the galloping sound and the nice lines on the timegrapher start to get interrupted and "snowy".

In an attempt to reduce the amplitude, I did put some heavy clock oil on the pallet-fork pivots, but no change. Since I was the first-in, I'm pretty sure that the main-spring is the original.

It could of course be that the NOS escapement-platform, even though identical looking, has a slightly different design? Perhaps a different design escape-wheel, different pallet-jewel impulse angels and/or a weaker hairspring ??

What other causes can there be, what can be checked / done other than installing a weaker main-spring?

Anybody some suggestions?

Hope to hear ..........

 

 

 

 

Edited June 15, 2023 by Endeavor