A very unusual English lever escapement

Discussion in 'European & Other Pocket Watches' started by Dr. Jon, Oct 11, 2019.

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  1. Dr. Jon

    Dr. Jon Registered User
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    I recently took watch out of storage that I had bought a long time ago. For a very long time I had considered it a bad buy since the maker signature seems to be a fake Dent. On a long ago trip to London I found the signer did run a shop, listed in a London business directory so they were operating openly.

    Let me share my detailed phots and show my very happy surprise.

    Here is the watch face. It is a 16 size hunter in a plain polished 18K English case.
    469975-d3edf03e27efb593da2ea0b9d40a986e.jpg

    It had very ugly Swiss replacement hands, which I just replaced.

    Here is the movement with the signature "E. B. Dent"

    movement_s.jpg

    face_s.jpg
     
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  2. Dr. Jon

    Dr. Jon Registered User
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    #2 Dr. Jon, Oct 11, 2019
    Last edited: Oct 11, 2019
    This is a second try for some reason the first one disappeared.

    I recently took a look at a watch I bought a log time ago and had considered to be a bad buy because its maker was possibly a counterfeiter and the hands were bad. I replaced the hands and took a look at the escapement and it is intere sting enough that I want to share it.

    Here is the dial with the replacement hands. face_s.jpg
    I would have preferred hands a but thinner and lighter.

    The movement is a good grade helical freesprung lever with going barrel in a plain polish 18K case. The case is dated 1879 by a maker in Bristol not listed in Priestley but teh maker's mark is on the case covers pendant and bow. Here is the movement.
    movement_s.jpg

    It is plain movement without engraving not a diamond endstone but a fairly typical ruby on in a blue steel setting, which is also common in watches like this.

    Here is the balance and spring.

    balance_s.jpg

    The roller and lever fork are the most unusual aspects of this watch so here are a few views of the lever fork end.

    dart1_s.jpg
    This is very elaborately shaped and large safety dart and unusually made of steel.

    Here is top view of the fork. dart2_s.jpg

    The fork is unusual in that has corners at the entry and the center is thinned.

    this shape is to accommodate a radial impulse and unlocking jewel shown on the next picture of the roller.

    roller1_s.jpg

    I have seen several lever escapements with radial jewels but this is the first with a true double roller.

    Another odd thing about this very odd roller is that it looks to have a friction staff. It tapers out from the roller so there is no way to drive this roller onto a riveted balance staff.

    I can write more on the rationale and possible origins of this arrangement but that will be by request since it is very esoteric.

    I'd love comments and and to know whether anyne has seen anything like this and any E. B. Dent watches.

    My visit to the Guildhall Library in London resulted in finding that E. B. Dent was listed in a London business directory but I have found no mention in Mercer's book on the Dents.

    Thanks for looking.
     
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  3. gmorse

    gmorse Registered User
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    Hi Dr. Jon,

    I recall seeing something very similar in a Parkinson & Frodsham a while ago, and also in one of Morton's 'London Patent Chronometers'.

    Regards,

    Graham
     
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  4. roughbarked

    roughbarked Registered User

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    E.B. Dent could just have easily been the retailer.
    Edward J. Dent appears to have been a watchmaker. "Edward John Dent (1790–1853), English watchmaker, London, pocket watch, marine chronometer. ...." from; List of watchmakers - Wikipedia
     
  5. John Matthews

    John Matthews Registered User
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    Dr Jon - a very interesting movement.

    I would be interested to see photographs of the case hallmarks and the maker's mark.

    Do you remember which trade directory E B Dent was listed?

    John
     
  6. Allan C. Purcell

    Allan C. Purcell Registered User
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    An interesting piece you have there Jon. I have of course had a look, and will look further for you. In the Dent supplement, the family tree was re-written, there were a few errors in the book. See below, the appended tree.

    g7.JPG
     
  7. John Matthews

    John Matthews Registered User
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    I knew there were aspects of the escapement that looked familiar ...

    I purchased this movement from David .. Edmond JOHNSON, Dublin. No 11000 - David Penney's Antique Watch Store - it has balance wheel features in common with your Dent and is also an unusual double roller

    upload_2019-10-12_10-22-38.png

    With this example the safety dart is above the impulse jewel

    upload_2019-10-12_10-45-58.png

    - as is yours.

    So effectively I believe the Dent can be described as an inverted double roller as in the normal double roller the safety dart is below the impulse jewel - please correct me if i am mistaken!

    For comparison the roller and dart of from one of my free sprung inverted double rollers from ~1885 ...

    20170825 004.jpg 20170825 002-2.jpg 20170825 005.jpg

    John
     
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  8. John Matthews

    John Matthews Registered User
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    I knew I had seen another similar - Ray posted here

    John
     
  9. Allan C. Purcell

    Allan C. Purcell Registered User
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    g-9.JPG Here is another Jon, from Robert Roskell´s 28015 c1820. A strange story really, the double toller went straight through from Mudge´s invention in 1757 to about 1820-then was ignored till about 1860 in England. Anyone know why.

    Going back to your question on E.B.Dent, I looked up the numbers for E.J.Dent and Numbers 907 to 927 was a batch by le Comte in 1849. Is it possible that there was an engravers fault?
     
  10. Dr. Jon

    Dr. Jon Registered User
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    Thanks for the replies.

    1) Here are the marks inside the back cover
    470063-9148dd1dd582e9dd5c2fe318eaf51298.jpg

    2) I looked over the updated family tree and did not find an E.B Dent of that time. E. B. probably used the "B" to avoid being prosecuted for using the Dent name. He may not have been a Dent, playing near the edge, but he seems to have sold very good watches. On this basis, I think he was an unrelated, or very distantly related Dent.

    3) Inverted double rollers are not that unusual on freesprung levers.

    The E. Johnson Dublin #11000 looks like a P&A Guye lever, and probably is. Guye was a wholesale factory. It is technically a single roller but I suggest it is a hybrid between the double and single. The safety is a smaller radius than a table roller, but not as much as a true double roller.

    The second example in the post (#5) is identical to a David Glasgow watch which was in the time Museum sale and I think I have seen others like it on freesprung levers

    I suspect the Parkinson and Frodsham example was by Walsh. They sent one of these to the 1876 Geneva trials and got a first prize with it.

    Here is another Walsh lever that came through the shop. It is a keyless fusee freesprung (duo in uno)
    470066-8d39f109c99d15edb2c10bd3b6c875f7.jpg



    470067-36f9b0973a14861f2fc780206f55f49d.jpg

    The gold color dart actually comes up and then bends over, which is not always clear in the photo. It too is an inverted "hybrid" roller as are the P. &A. Guye examples.

    The E. B. Dent is the only radial jewel true double roller I have seen.
     

    Attached Files:

  11. John Matthews

    John Matthews Registered User
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    Dr Jon - my thanks for your helpful comments and additional information.

    I have never seen reference to the difference in the dimensions of the roller and safety as being a being critical in defining a 'true double roller'. My understanding has always been that if the safety radius was less than the impulse radius it was a double roller and vice versa for a single roller.

    Are you aware of a progression of the dimensions with time?

    There are two matching marks listed in Ridgeway & Priestley. White & Hawkins, Legge Street, Birmingham - not Bristol. They are listed as silversmiths & goldsmiths with the mark dated 10/06/1874. However more likely, there is a mark recorded in the Chester 'Large Punch Book' on 11/12/1878 for Louis Weill & Henry Harburg (watchmakers), 14 Hatton Garden. The fact that neither of the two entries are identified as case makers, explains their absence from Priestley's publications. Weill and Co has a substantial biographical entry in Vol II of Culme with Weill & Harburg dating from 1876 to 1890. Harburg & Feis are identified as wholesale & export watch manufactures based in Chaux de Fonds - my guess this is where your movement may have started its life.

    I could find no reference to a Bristol based matching mark in the Chester records.

    John
     
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  12. Dr. Jon

    Dr. Jon Registered User
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    The essential idea of the double roller is to reduce the safety radius as much as possible. It has the additional benefit that the safety dart can be much more rigid and a table safety pin (unless it is a Swiss knife edge) and shaped to minimize the effect of it striking the roller. The Guye and Walsh rollers reduce the safety radius but they are a single element. My definition of a double roller is that it is a double roller, i.e. that there are two rollers. It is bit tricky since many double rollers are a single part, as the one on the E. B. Dent probably is. At this point we are probably splitting hairs but to me a true double roller has a separate disk radius away from the notch.

    I do not know what the progression in time was and I would be surprised if such happened. Double rollers go back to the first levers.

    What I have found is that there was a revival or radial impulse jewels in the 1870's up to the 1890's. Chamberlain has a discussion of this in terms of some patent activity.
     
  13. John Matthews

    John Matthews Registered User
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    To be correct 'escapement' started life ...

    John
     
  14. Allan C. Purcell

    Allan C. Purcell Registered User
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    Looking at Priestley for your WH. I too was a bit put off, for the sponsor's mark on your watch looked quite clear. Then I found WIH, for William John Hammon II (See WH). Witch I did and we have William (John) Hammon II (see other Hammons) 8 Fleet Street, Coventry. this in 1862. His mark also London and Chester. His address in London 1860 was 11, Sekforde Street Clekenwell. Allan.
     
  15. Dr. Jon

    Dr. Jon Registered User
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    To Allen's question in post 7 .

    The double roller did go away in about 1820. My speculation is that this happened at the same time makers figured out that they needed draw to make the lever reliable. This was a real deal breaker for most makers. In short, the improvements over the verge, the cylinder, virgule, and duplex for example were to make the escapement dead beat. I believe the rack lever was another reaction to this realization that a detached lever could not be dead beat. It is manifested by the absence or extreme rarity of precision lever watches from 1820 until about 1850, shortly after the Great London exposition.
     
  16. John Matthews

    John Matthews Registered User
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    I agree it is splitting hairs in some respects.

    The problem I find is that it difficult to make the distinction between the geometry of the action of the escapement based upon the physical design of the rollers, i.e. whether there is one or two. My personal view that the use of the term 'roller' is unfortunate as it puts the emphasis on the physical shape. I have always ascribed greater significance to the relationship between the impulse and guard circles. You pays your money and takes your choice.

    Gasley starts his section on the single roller with 'A single roller must be considered as two rollers in one, the impulse-pin circle being taken as one roller and the metal outside this as the guard roller." and in his section on the double roller 'The double roller was invented by Thomas Mudge and was incorporated into the first detached lever watch ever made'.

    John
     
  17. Dr. Jon

    Dr. Jon Registered User
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    I used to think the roller was less important than the impulse/unlock jewel and safety dart or pin but I now believe the safety roller radius is important. Safety was the reason draw had to be introduced with its "loss of innocence" . In real life watches get jarred and the safety action of the pin or dart can have a lot of impact on watch rate in real life. The double roller reduces the safety acting radius to a minimum.

    I just read Borer's book on watch making, written in the late 30's. He argues that a single roller just is not strong enough for a wrist watch to give good performance and something like playing the piano is enough to make this difference.
     
  18. John Matthews

    John Matthews Registered User
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    My apology in advance if I am missing something - but does not this statement put the emphasis on the safety circle - i.e. the roller design is driven by importance of minimising the safety circle, I don't see how this necessitates two physical rollers. I have read that the reason is that the single roller was easier to make by hand, but more difficult to make in mass production and that there was a move to make the two rollers as a single unit, again for production reasons.

    John
     
  19. gmorse

    gmorse Registered User
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    Hi John,

    'Watchmaking' chapter 8 and particularly page 214.

    Regards,

    Graham
     
  20. Allan C. Purcell

    Allan C. Purcell Registered User
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    g10.JPG I don´t think everyone as a copy of Daniel´s Watchmaking-so her it is. Regards, Allan
     
  21. John Matthews

    John Matthews Registered User
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    #21 John Matthews, Oct 12, 2019
    Last edited: Oct 12, 2019
    Graham - I believe I do understand Figure 453 in Daniels - but if I am mistaken please correct me.

    The diagram introduces the length of the lever and shows that with a shorter lever you need to have the safety circle less than the impulse circle - that is all. You could accommodate that with a 'single piece roller'. viz a thick one piece roller, providing the 'slot' was sufficiently deep to accommodate the safety date.

    This has not changed my view that it is the relative size of the impulse and guard circles that is the important characteristic to distinguish what we normally describe as single or double roller - not whether there are two distinct rollers in the physical sense.

    How would you describe a escapement with two physical rollers if the guard roller had a greater diameter than the impulse roller?

    John
     
  22. Ethan Lipsig

    Ethan Lipsig Registered User
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    Some of this thread is about impulse jewels, some of it is about safety darts, and almost all of it is above my head. I do want to report that I have a free-sprung minute repeater, almost certainly Swiss, that has an inverted double roller and an English-style side lever escapement. Unfortunately, I do not have any good photos of these features. Because they seem to go together, was there something about a free-sprung movement that warranted using an inverted double roller?
     
  23. Allan C. Purcell

    Allan C. Purcell Registered User
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    Ethan, I like you I am waiting for Graham´s answer-should be a crackero_O.
     
  24. John Matthews

    John Matthews Registered User
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    Ethan

    For reasons, I don't understand, it is true that many inverted double rollers, are freesprung. To understand, I would need to understand why a particular watch was designated to be freesprung. I don't.

    John
     
  25. Dr. Jon

    Dr. Jon Registered User
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    I think the reason was vanity. Freesprung levers were top of the line except for complications.
    The escapement makers liked to do something special on these and were probably paid extra to do it.

    The other aspect is that it i possible to see the dart when the double roller is inverted and these darts are works of art. In the normal configuration the dart is really visible only with the balance removed which most owners were not going to do.

    They had no chronometer certification so the high end watch had to show it was high end by features visible to the buyer. Freesprung, often diamond endstones, and an inverted double roller are things a seller can show a buyer. They are arguably functional features rather than decoration like engraving.
     
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  26. gmorse

    gmorse Registered User
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    Hi John,

    Yes, except that the impulse pin and the passing crescent necessarily have to be in alignment, and since it's more desirable that the safety radius is less than the impulse radius, this ends up being two rollers of different radii; how this is physically constructed matters little to the underlying concept of operation. This is just a confirmation of your following paragraph.

    Exactly.

    Probably as a failed experiment . . .

    I was a little prescriptive in my reference to 'Watchmaking' in post #19, I think I should just have recommended the entire section on levers in chapter 8, which goes into the relative geometries of the two roller types.

    Regards,

    Graham
     
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  27. John Matthews

    John Matthews Registered User
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    :)

    John
     
  28. Allan C. Purcell

    Allan C. Purcell Registered User
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    Geroge Daniels "The action occurs equally on each side of an imaginary line drawn through the pivot centres" Never fails.
     
  29. Allan C. Purcell

    Allan C. Purcell Registered User
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    #29 Allan C. Purcell, Oct 17, 2019 at 2:36 PM
    Last edited: Oct 17, 2019 at 2:41 PM
    Yesterday at 10:26 AM
    Catalogue of Waltham Watch material: Waltham Watch Company: Free Download, Borrow, and Streaming: Internet Archive The whole book to look at here.

    American Waltham Watch Co. Material Catalogs and Advertising | Pocket Watch Database

    I put these catalogues on the board for someone else, who wanted dated Waltham catalogues, but I did have a look through them myself. On the second thread here, in the little blue book, there is a very interesting graphic and explanation of the Jewelled double roller escapement used by Waltham in 1909. Look for the "Jewel Pin Action" page 33. Enjoy.

    Regards,

    Allan
     

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