Strange Brockbanks Conversion??

Discussion in 'European & Other Pocket Watches' started by Allan C. Purcell, Sep 29, 2019.

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  1. Allan C. Purcell

    Allan C. Purcell Registered User
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    I found this Brockbanks movement laying a plastic bag among the cheap stuff in a Watch & Clock mart in Recklinghausen yesterday. I am no expert when it comes to the mechanics, but I do think this watch is converted from verge to cylinder, plus it has holes in places you would expect even then, or when it was converted. So here are the photographs for you to look at. Though it will cost me to get it running, I think it will be worth it just for the dial, it is almost perfect. If I am correct those pins sticking out of the balance could have been left-over from the verge, but then again maybe not.

    Allan.

    e-1.JPG e-2.JPG e-3.JPG e-4.JPG e-5.JPG e-6.JPG e-7.JPG

    e-9.JPG e-8.JPG
     
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  2. Lychnobius

    Lychnobius Registered User

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    From the images it looks as if the hole where the balance-staff passed through the back-plate is circular; in a movement built as a verge, would it not have been squared off to allow space for the vertical crown-wheel?

    At the same time I can see why Allan feels that this movement has been modified in some way, since the inner profile of the barrel-bridge suggests that the balance-wheel was once considerably larger.

    The protruding and squared-off end of the barrel arbor is curious. I suppose this could mean that the movement was designed to have an exposed set-up on the barrel-bridge but that this was never actually fitted, or else that it was removed and a new barrel-bridge, with no provision for the set-up wheel, was subsequently added.

    Oliver Mundy.
     
  3. John Matthews

    John Matthews Registered User
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    Allan - I think the balance wheel is a replacement.

    Here is my 1806 Brockbanks cylinder #4750

    20170114 011.jpg

    John
     
  4. Allan C. Purcell

    Allan C. Purcell Registered User
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    Oliver, John, Thank you for your remarks, they are food for thought. Though I must ask John is your Brockbank a verge, and there appears to be a pin sticking out on the balance just above the letter N? In the first of my photographs, you will notice there are extra holes too, and it could be the cock was of the wider old fashioned type. I did say the watch was strange. If the balance wheel is a replacement (more than possible) why did they leave those strange pins in there? I think I will send it to Golders Green.

    Regards,

    Allan.
     
  5. John Matthews

    John Matthews Registered User
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    Allan - as I said it is a cylinder, and it has always been so.

    You are correct there is a pin set into the balance wheel. At rest you will see it is aligned with the escape wheel pivot. I don't know, but I suspect this alignment has significance in terms of positioning the balance/cylinder. In operation the balance rotates ~45° either side of the rest position.

    John
     
  6. Allan C. Purcell

    Allan C. Purcell Registered User
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    Reading to quick John, anyway, it seems those pins were a safety device, when the watch is roughly used, among other things.

    Quote from "Saunier´s Treatise" Bethoud was the first to clearly lay down rules for the construction of this escapement, but his theory of dead-beat escapements in watches is generally admitted at the present day to be erroneous in many particulars. Nevertheless, credit is due to him for his work, and in reading it we must remember that at his time, owing to an opinion accepted without question amongst watchmakers, the escape-wheels of cylinder watches were formed of brass of considerable thickness, the oil was rapidly decomposed, and the teeth, in the case of light wheels, were liable to be strained by touch of the workman, and wore away with far greater facility than does a steel wheel under the same pressure. The cylinder was usually thick and heavy, and the balance light but of considerable diameter. The pivots, as a rule, thicker for a given sized cylinder than they are at the present day worked in brass holes which gradually became larger and so changed the relative positions of the working parts. It will be evident that under these circumstances the cylinder watches of that period were sure to be characterized by excessive and very variable friction, and the irregularities, especially those due to changes of temperature, were much greater than occur in modern watches. If we observe that as a rule the arc of vibration of the balance was shorter than that now in vogue, that the number of vibrations formerly never exceeded 14,00 to 16,00 per hour, and at the present day is increased with advantage to about 18,000, and that the use of the fusee, then almost universal, had the triple objection of being useless, of involving a needless increase in the motive force, and of causing, more especially when the oil was at all thick, a setting at the time of winding; it will be evident why this escapement gave rise to so great a diversity of opinion among watchmakers of the last century. Such a diversity of opinion is no longer justifiable at the present day when we can study it confidently and with profit by the light of long and well-directed practical experience, and with the science of machine-constructed in a highly advanced condition."

    I have also read up on the Brockbanks in the AHS vol. 26- sept. 2001 page 244. by Mr F. von Osterhausen. Very good article.

    Allan.
     
  7. Jerry Treiman

    Jerry Treiman Registered User
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    Again, for comparison, here is my Brockbanks cylinder No.5548. The large steel balance wheel is well proportioned to the plates, further suggesting that Allan's may be a replacement. A small pin is visible in the edge of my balance (at one of the arms) and it appears to bank against a brass block that is hidden underneath the balance cock.
    Brockbanks_5548m.jpg
     
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  8. DaveyG

    DaveyG Registered User

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    #8 DaveyG, Oct 2, 2019
    Last edited: Oct 2, 2019
    Allan, I'm not sure that I see the relevance of the extract from Saunier at your post above vis a vis the unusual arrangement of pins on the balance rim. I think that a more pertinent point you will see if you read Saunier Chapter 425 'Over-Banking of the Balance'. I won't repeat it all as it is quite lengthy but the most relevant points are that:

    1. The balance in a cylinder watch is capable of performing a complete rotation.

    2 Over-banking is avoided by fixing in suitable positions the cock banking stud and the banking pin in the balance.

    The balance on this watch is unusual in that it has two pins, but I can see the sense of that in that it limits the possible over rotation of balance to a greater extent than a single pin. Whether that has something to do with the balance being a replacement (or an original of different proportions) would need careful examination. Whatever, they are in the wrong position to be effective as they appear at the moment.
     
  9. Allan C. Purcell

    Allan C. Purcell Registered User
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    Jerry, Thank you for the above, I think that is quite right about the balance being too small. When reading the AHS piece by Osterhausen, he says the numbering will be in another copy later. Does anyone know if that happened? Allan.
     
  10. Allan C. Purcell

    Allan C. Purcell Registered User
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    Dave, Sorry about that, my fault not to have put in the above from you. I had already found that in the article in the AHS , though the Saunier piece makes it quite clear. I think after copying the above, I just got lazy. I will try harder OK:(
     
  11. DaveyG

    DaveyG Registered User

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    No worries Allan - not after smartie points just trying to help ;)
     
  12. DaveyG

    DaveyG Registered User

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    No worries Allan - not after smartie points just trying to help ;)
     
  13. Allan C. Purcell

    Allan C. Purcell Registered User
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    No worries Dave, I would have done the same. I just think about who tampered with this watch, I cannot for one minute think it was Brockbanks. Another strange thing is those three little holes on the edge of the top plate, could it be vandalism? We will probably never know. Has your friend Einstein says- "Time is an illusion"
     
  14. Allan C. Purcell

    Allan C. Purcell Registered User
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    Hi, Dave-I have been writing a few lines on the Horological Books page, and I wanted to mention "Clocks & Watches An Historical Bibliography" by G.H.Baillie. I had intended to praise the book but thought if I were to do that I should at least go through it a few times because I had not read through it for more years than I can remember. So I will get to the point I had read in one or two other books that Tompion had invented the cylinder escapement, and Graham improved later, and I have also read it was only an idea by Tompion and it was Graham who developed it. While going through the above I stopped at 1737. SULLY; HENRY AND LE ROY; JULIEN. Then there is a large paragraph in French, I then skipped over to the next paragraph in English, and it reads, Pages 1-238 contains the matter of the 1717 edition, but without the letter from Kresa and Sully´s reply. Pages 239-272 contain Histoire critique de differentes sortes d échappements Par Mr Henry Sully, horolger. (critical history of the different kinds of escapements) This is probably a part of the projected treatise on horology, see Sully 1728. (Sully died in 1717 so never got to finish the treatise) Baillie then writes " Then follows the only description I know of Tompion´s escapement of 1695 resembling the cylinder, as follows, in translation-" He then writes that up, and then at the end he writes. " but the continual friction of the escape wheel against the cylinder, and the increased friction on the pivots of the balance wheel...were harmful to the accuracy of the watch; on this account he abandoned it as soon as he found its imperfections". So I would say Tompion did invent the cylinder escapement, no matter what Graham did to it? Allan.

    PS: I am still reading the book- I am away at the weekend, I think I will take it with me.
     
  15. John Matthews

    John Matthews Registered User
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    Allan

    If you have a copy of Ballie's 'Watches - history decoration and mechanism' (1929 reprinted in 1979) there is a description of the 1695 patent of Barlow, Houghton and Tompion 'for a new escapement' on pp. 276-277. The implication is that the patent was solely descriptive and there were no illustrations. Bailie concludes ...

    'This has been regarded as the cylinder escapement, but, in the absence of more particulars of which the Author has no knowledge, the description, though applicable to the cylinder escapement, is too vague to prove the invention of this escapement by Barlow, Houghton and Tompion.'

    Baillie expresses his view that George Graham 'invented the cylinder escapement in its present form about 1725, and introduced it into France by sending a watch to Julien Le Roy'. I have seen other authors use the phrase that Graham 'developed the cylinder escapement'

    However, if you look at Britten 1894 book on p. 86,

    'Prior to September, 1695, Tompion produced a watch in which the teeth of a horizontal escape wheel dropped on to a cylindrical body of a verge ... and in September 1695, he, in conjunction with Booth and Houghton, patented the cylinder escapement.'

    With this description there is a small thumbnail illustration, which has some minute annotation, from which I infer it is imported from a source, that is not referenced.

    On p. 89 ...

    'After the expiration of Booth, Houghton and Tompion's patent, Graham devoted some thought to the cylinder escapement, which in 1725 he modified to practically its present form and introduced into some of his watches.'

    This all I can offer, but I would think there are many on this forum who will be able to provide more.

    John
     
  16. Allan C. Purcell

    Allan C. Purcell Registered User
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    John, Thanks for the above, it is most useful. but I am in a hurry, we are out this weekend, could write more Sunday night. Baillie wrote the above before 1929, he only found the Sully documents in the 1940s, and the book I quoted came out in 1951, first edition. I will write up what he said then. Best wishes, Allan.
     
  17. John Matthews

    John Matthews Registered User
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    The diagram is taken from Rees ...

    Plates001.jpg
    This is what Rees has ...

    First dead beat escapement by Tompion. - The ingenious Tompion of London was probably the first watch maker who contrived an escapement without recoil, or escapement of the second class, called dead-beat escapement from the circumstance of the second hand remaining motionless, or, as it were dead, during the motion of the balance after the escape. Sully says that he succeeded in effecting this about the year 1695. In this escapement of which Fig 7 is the plan, the balance verge carried a cylindrical piece of metal a b c, terminating with a pallet c, with a notch cut between a and c to allow the escape of each successive tooth of the balance wheel. This wheel had its plane parallel to the plates of the frame, and its teeth bent at the end and so distant that the cylindrical piece and pallet could revolve between the two of them.When the cylindrical part of the pallet presented its notch to the contiguous tooth of the escapement wheel, it received a push therefrom, which put the balance in motion in the direction of c b a, resting against it without recoil till the the balance spring had brought the notch back again when it escaped in its turn by giving its push and a third tooth fell on the cylindrical part of of the pallet, and in like manner remained motionless till the notch came back again and allowed the escape: thus one escape took place at every alternative vibration, and the contrivance was admirable calculated to prevent the bad effect on the balance of any change in the impulse derived from the mainspring; but the friction on the back of the pallets when large, and at the balance pivots occassioned by the pressure of the resting teeth, constituted the same objection in practice as applied to De Tertre's modification of the escapement with two balances. This escapement, however, was the archetype of all the succeeding dead-beat escapements and is therefore deserving of the notice we have given to it.

    Subsequently, in discussion Graham's cylinder movement Rees notes ...

    The contrivance bears a great analogy to the Tompion escapement and was probably derived from his, which, however, does not lessen the merit of the contrivance, as it requires as much ingenuity to improve an existing instrument, frequently, as it does as it does to invent a new one ....

    Plates002-2.jpg

    John
     
  18. Allan C. Purcell

    Allan C. Purcell Registered User
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    John, It would appear Baillie was a little confused when writing up his remarks on the Cylinder escapement, he must have read the above in Ree´s, which about says it all. You can summarise the above with just, Tompion invented the first dead beat escapement, and George Graham improved it. Though as promised, here is what Baillie wrote in 1951,

    "Then follows the only description I know of Tompions´s escapement of 1695 resembling the cylinder, as follows in translation:- The verge carried a cylindrical portion of about 1.5 lines in diameter; the escape wheel was parallel to the plates, and its teeth were spaced sufficiently to allow the cylinder to turn freely between them. A grove made in the cylinder in the direction of its arbour. formed a pallet which presented itself to the action of the escape wheel, the first tooth, in turning the pallet away escaped from it, and the following tooth dropped on the cylindrical portion and was stopped by it until the return of the balance brought the groove to this tooth, thus giving only one beat for two swings of the balance. This escapement had the excellent property that the movement of the watch was not affected by changes in the motive force: but the continual friction of the escape wheel against the cylinder, and the increased friction on the pivots of the balance wheel....was harmful to the accuracy of the watch; on this account he abandoned it as soon as he found its imperfections". :(

    Not that any of this explains the two pins on my Brockbanks movement. Allan:rolleyes:
     

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