verge escapement

[roger naughton 1Participant @rogernaughton1]

is it possible that some-one can explain how to set a verge escapement in beat?  thanks

[roger naughton 1Participant @rogernaughton1]

[Richard ParsonsParticipant @richardparsons61721]

 

The beat of a verge escapement is a regulated, in the main, by power available to drive it. Verges are very sensitive to this. Looking after the verge was a specialist job. In the monasteries it was done by a brother called the ‘Verger’.

If you are using a foliot then it is regulated by the weight of the weights and their position along the foliot arms. The heavier the weights and the further they are from the centre the slower the beat.

If you are using a balance wheel you can only regulate it modifying the power input. If your balance wheel is running slow you can lighten it. That is what my old friend Bill did. If it is too fast you try to add weight.  Of course you can always make a new balance wheel –Bill had to make 4 or 5 to get it on beat. With a very small balance wheel the old‘uns used a hog bristle on the banking arm, but your barber would need a few confidential minutes with a large old porker. (Honest Mr Policeman the pig has not got rabies that is shaving foam). This bristle checked the swing of the balance wheel

If you are using a pendulum you need to make a pair of cycloid cheeks these change the path of the pendulum swing from a circular to a cycloidal path when the suspension chord strikes one of the cheeks.

Another problem is that you have to minimise the ‘drop’ and make it equal.

There is a very good descriptionin Clock and Watch Escapements by W.J.Gazeley

Whilst I am here, does anyone know of an escapement called a whip escapement. This was an arm with a string with a weight on the end. The whip struck a pin the weight spun the cord round the pin two or three times. This checked the rotation of the whip arm. When the whip weight unwound the whip arm spun on round until the whip hit the next pin.  It is to timekeeping as late and very unlamented Mr Hitler was to Jewish charities.

[Roger HartParticipant @rogerhart88496]

I have done 2 of these.  First set the verge leaves to be equiangled about the foliot or balance wheel pin.  Next adjust the balance spring so the foliot or balance sits halfway when in the movement.  Then set the escape wheel a little way out from the verge leaves and try gently with your finger,  advance the escape wheel to improve the action.  Adjust the lateral position of the escape wheel to achieve the best (least worse) beat.  Assemble and try.  Repeat as required – I found it a pretty frustrating business on verge watches.

 

What seems important is to make sure the acting faces of the verge leaves are a flat mirror polish – without this you are wasting your time.  If you are making the verge staff then some careful grinding of the verge leaf tips may be needed – but keep them polished. 

[Richard ParsonsParticipant @richardparsons61721]

 

Roger I will agree with you about polishing the Verge leaves. You also have to make certain that that the teeth on the ‘scape wheel are all the same height relative to the verge staff. For a verge to be successful accuracy is essential. The foliot and pendulum are easier to being into ‘beat’ than the balance wheel, but they are not so ‘handy’. The balance wheel system was often used in watches of the period. There was one in the Ashmolean museum Oxford, but someone changed the movement in the 18^th Century.

PS.  I used dry ptfe lube on the verge leaves or palletts.  Spray it on and polish it off. 

Edited By Richard Parsons on 17/10/2010 11:16:19

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