Adjustment of banking pins

[Snapper]

Although this question concerns a clock, the platform escapement is probably more akin to watch repair so please forgive me for posting in this forum.

I don't usually work on platform escapements but as this is my own cherished Chelsea clock I will have a go. After running beautifully for several years, it suddenly came to a stop with the escapement locked. My investigation found that the left hand banking pin in the photograph had worked loose, allowing the impulse jewel to "escape" from the lever fork. I have never had to adjust banking pins before so could I ask for advice on how to go about it please? Also, when correctly adjusted, is it acceptable to lock it with low strength Loctite?

 

[glenhead]

You want the drop to be the same on both sides. If the pin on the right is in its original position, move the fork over to that pin. Note where the escape wheel tooth hits on the pallet stone. Move the fork to the other side and adjust the pin until the tooth on the left hits the stone at the same place, or at least as "same" as possible without fancy expensive measuring gizmos.

Once you have it adjusted there's no real reason to change the pins again. Loctite to secure the loose pin would be a good (reversible, if necessary) solution.

Hope this helps.

Glen

 

[gmorse]

Hi Snapper,

Just to be clear, with the lever against one banking pin, the jewel on that side should be locking the escape tooth with its locking plane, (in red), and not with its impulse plane, (in green). If the banking pin that side won't let the jewel go deep enough into the escape wheel to lock on its locking plane and just hits the beginning of the impulse plane, that's the pin to move out a little.



If it's been running for several years, is it due for a clean and overhaul?

Regards,

Graham

 

[Karl Burghart]

Wear on these direct train escapements is very common. The lower hole for the escape wheel is one I find to often have severe wear. It can be difficult to see if you're not looking for it. I normally install a jewel there. Most of the time it's a 90/30. Before moving a banking pin be certain it wasn't because the escape wheel or pallet fork are moving out of alignment.

 

[Snapper]

Many thanks for the replies. I will check the escape wheel holes as looking from the side, the escape wheel does not sit exactly parallel with the cock and platform. I have had to put the clock on the back burner at present owing to other work coming in but I will report back at a later date.