Identifying Massey escapements without dismantling

Discussion in 'Highlights' started by Lychnobius, Apr 2, 2020.

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  1. Lychnobius

    Lychnobius Registered User

    Aug 5, 2015
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    Semi-retired designer & printer
    Redruth, Cornwall, UK
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    #1 Lychnobius, Apr 2, 2020
    Last edited by a moderator: Apr 2, 2020
    In discussing English fusee lever movements made between about 1812 and 1850, we often come up against the question whether the escapement is a standard English single-roller pattern or one of the five styles developed by Edward Massey from 1812 onwards. One can usually recognise the Massey types, and even distinguish one from another by looking through the side of the movement (obviously with the dust-cap removed if there is one), but this inspection is not always possible, especially if one is trying to evaluate a watch or movement solely on the basis of online images supplied by a vendor or an enquirer. However, it seems to me, from my admittedly limited experience, that there may be a clue – I do not say it is a decisive one – in the position of the banking-pins: that Massey levers tend to be a little shorter than standard single-roller levers, and therefore that in the former the pins, whose ends can be seen on the back plate, will be further from the edge of the plate than they are in the latter.

    By way of evidence, I give below images of two Joseph Johnson movements of about 1823: No. 5680, a Massey I, and No. 5687 which was (alas, I no longer have it) a standard English lever. These two are in most respects as nearly identical as any two hand-made articles could possibly be, but in 5687 the pins are visible towards the right-hand side just clear of the perimeter of the balance, whereas in 5680 the pins are further enough inboard to be actually under the rim of the balance.

    It may be that this is a false scent and that the movements I have been able to inspect are too small a sample to justify any conclusion. That is precisely why I am asking those of you who have many such movements at your disposal, or who have seen more than I have, to consider whether my suggestion is valid or not. It may not be; but if it is, this may make it a little easier for us to draw conclusions about items which have been posted here for discussion, which we are thinking of buying, or which those of us who have the craze for compiling databases are trying to describe to the best of our ability. Of course one would still have to inspect the movement itself in order to say which Massey type was present, if any; but at least my idea, if it is sound, would limit the options.

    Besides the two images just mentioned, I have added a sketch (adapted from one in my Johnson database) of the various types of escapement in question; the upper row shows what one will see mounted on the balance-staff between the plates, while the lower illustrates the different styles of the forked inner end of the lever.

    Oliver Mundy.

    johnson_3.jpg johnson_5680_back_03.jpg horology_escapement_types.jpg

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