Banking Pins

[digginstony]

Hi Guys,

I have a basic question. When the balance comes to a standstill. Where should the entry and exit stone be resting in relation to the escapement wheel.

This knowledge would be of great assistance on a "

Initial Set Up" yet I can't find reference to it. Have posted what I do have below.

Any diagram would be great.

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[StuartBaker104]

If all is good and your hairsping is correctly aligned on the balance wheel, then with no power on the mainspring, you should land at Figure C, but I have no idea how you will use this information!

[digginstony]

If all is good and your hairsping is correctly aligned on the balance wheel, then with no power on the mainspring, you should land at Figure C, but I have no idea how you will use this information!

I was given a Waltham movement mod 1908. Where the guy disassembled it, including the banking pins. Walthams are not fixed they are threaded and rotate.
I wouldn't normally touch these they are factory set. I've reassembled the movement and without power I will set the Banking pins so the Entry stone corresponds to Figure C. And work from there.
Many thanks

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[Tmuir]

If you can find a copy of 'Know the Escapement' by Sarah & Homer A Barkus it goes into great detail about how much clearance there should be, but they only printed 5000 copies in the 1940s, so its hard to come by, but they do turn up on ebay.

[JMElam]

To understand this theory please first imagine a straight line drawn through the escape wheel pivots, lever staff pivots and balance staff pivots. when this line is created the lever must also follow, the spring must be quiescent or in it's unstressed condition with the roller impulse jewel resting in the centre of the lever forks slot, this position is the most favourable for impulse, because a small impulse is sufficient to unlock the escape wheel and energize the balance under the least resistance of the spring. This is essential if the escapement is to be self starting from the run down condition. The quiescent position of the spring is then the centre line of the escapement. 

*Please note that the diagram you provided is how the escapement works, and all though figure (C) shows the correct positional locations for the pallet and escape wheel tooth for the escapement to be self starting, the angle of the lever is not ideal, it is not straight and will create an oscillation that is not isochronous. 

When the line is created an escape wheel tooth must be over either the entry pallets impulse surface or the exit pallets impulse surface, either is sufficient to create a self starting escapement. The creation of this centre line is also a must for the escapement to be in beat.

The position of the banking pins is crucial if the unlocking, impulse, lock and run to the banking is to be set correctly, this will require most careful and precise craftsmanship if the escapement is to work well. 

Most tedious examination will be required to set these correctly. Keeping close attention to the locking depth and drop of the escape wheel teeth to both the entry and exit pallets. 

I hope this explanation helps. 

[digginstony]

To understand this theory please first imagine a straight line drawn through the escape wheel pivots, lever staff pivots and balance staff pivots. when this line is created the lever must also follow, the spring must be quiescent or in it's unstressed condition with the roller impulse jewel resting in the centre of the lever forks slot, this position is the most favourable for impulse, because a small impulse is sufficient to unlock the escape wheel and energize the balance under the least resistance of the spring. This is essential if the escapement is to be self starting from the run down condition. The quiescent position of the spring is then the centre line of the escapement. 

*Please note that the diagram you provided is how the escapement works, and all though figure © shows the correct positional locations for the pallet and escape wheel tooth for the escapement to be self starting, the angle of the lever is not ideal, it is not straight and will create an oscillation that is not isochronous. 

When the line is created an escape wheel tooth must be over either the entry pallets impulse surface or the exit pallets impulse surface, either is sufficient to create a self starting escapement. The creation of this centre line is also a must for the escapement to be in beat.

The position of the banking pins is crucial if the unlocking, impulse, lock and run to the banking is to be set correctly, this will require most careful and precise craftsmanship if the escapement is to work well. 

Most tedious examination will be required to set these correctly. Keeping close attention to the locking depth and drop of the escape wheel teeth to both the entry and exit pallets. 

I hope this explanation helps. 

The position of the lever in diagram C was confusing; it definitely looks off centre. I've followed all advice and the good news is the movement is ticking away.
The bad news is its coming to an abrupt stop, intermittently! Sometimes after a few seconds and sometimes after 10 minutes or more. This is with the movement face down in a holder kept absolutely still with no change of position.
I think I need to make more adjustment as the exit stone appears to be jamming. The slightest touch of the escapement wheel with a small screwdriver starts the movement working again. I think the exit stone is going too deep into the escapement wheel, even though the wheel is Turning several revolutions before jamming. Or am I missing something else ?
Anyway I've put the movement away and will have another look next weekend and report back.
Many thanks for all the advice and help who contributed to this thread.

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[JMElam]

If you can provide a close up video of this happening, it will be easier for the group to help diagnose as theoretical and practical horology can be different.

However theoretically it sounds like more examination and adjustment is needed in the escapement. 

 

 

[digginstony]

If you can provide a close up video of this happening, it will be easier for the group to help diagnose as theoretical and practical horology can be different.

However theoretically it sounds like more examination and adjustment is needed in the escapement. 

 

 

I will make an adjustment next week. If the issue isn't resolved. Will video but it's a bit like sitting there waiting for paint to dry. If I spend anymore time upstairs now I think my Mrs will shoot me.
I know there's power through the train. All the wheels and teeth are good, including all pinion gears.

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[jdm]

11 hours ago, Tmuir said:

If you can find a copy of 'Know the Escapement' by Sarah & Homer A Barkus it goes into great detail about how much clearance there should be, but they only printed 5000 copies in the 1940s, so its hard to come by, but they do turn up on ebay.

Lots are available https://www.abebooks.com/book-search/title/know-escapement/ from $30.

[JMElam]

14 minutes ago, digginstony said:

I will make an adjustment next week. If the issue isn't resolved. Will video but it's a bit like sitting there waiting for paint to dry. If I spend anymore time upstairs now I think my Mrs will shoot me.
I know there's power through the train. All the wheels and teeth are good, including all pinion gears.

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I look forward to your update.

Patience is a most desirable attribute for the horologist, and the horologists Mrs  but if you're to succeed in this field then the time should not be of a concern. 

I too spend an inordinate amount of hours in my studio. 

[digginstony]

I look forward to your update.

Patience is a most desirable attribute for the horologist, and the horologists Mrs [emoji6] but if you're to succeed in this field then the time should not be of a concern. 

I too spend an inordinate amount of hours in my studio. 

Well I've spent many hours on this movement and am glad to say after making more adjustments ie..
Further adjustments to the banking pins.
Setting the watch in beat everything the pins are moved and
Also poise the balance as I observed a slight "Roll Back" and power loss in a couple of positions.
The mainspring is ok but needs replacing. It's not completely "Set" it's expanding to about two and half times the size of the watch but could do with being better than that. Also this may improve the amplitude as it's on the low side.
The watch has been running for over 24 hours in all 6 positions and has lost 3 minutes which I'm not particularly concerned at.
It's been an interesting exercise and have gained knowledge particularly how everything in the Escapement interacts with each other and has to be perfect harmony.
Have some final tweaking to do. Everything looks and sounds good but my timegrapher is saying the movement is a little out of beat.
Again many thanks to help received but can't leave the thread without a couple of pictures.


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