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    Senior Member JunMel's Avatar
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    Default The Miyota Parashock

    Well guys, I don't want to rob David of a nice Seiko thread so here's just another thread intended for a brief visual lecture on Miyota Parashock.

    Miyota's 82xx calibers are among the most popular Japanese watch movements alongside Seiko calibers not only in Japan but worldwide. In this thread I will attemp to discuss the characteristics of the Miyota Parashock used on almost all Citizen lines of beautiful watches. Since I will focus on the shock resist system, I used the manually wound Miyota caliber 8260A, the base for Miyota 82xx automatic movements.

    This beauty was and still a joy to wind manually. Winding is silken smooth and since it has a power reserve of about 45 hours, it is isochronous for 36 hours which makes it very accurate. I use it together with other calibers as references.

    Behold the Citizen New Master 22:
    Citizen New Master 22.jpg
    * Take note of the use of Crown emblem before the automatic 7's came.

    The Miyota (Citizen) 8260A is tha base for all Miyota (Citizen) 82xx calibers. Very dependable, very durable. I give credit to ingenious Japanese engineering.
    Miyota 8260A Manual Wind.jpg
    * Note again that it utilizes a single power train bridge aside form the balance wheel bridge, just like most Seiko calibers. Miyota employs the sweep second pinion and pressure spring design seen on earlier Swiss calibers.

    Brief specs:
    Manual wind (base for Miyota 82xx automatic calibers)
    21,600 vph
    17 Jewels
    Central sweep second pinion and pressure spring
    Parashock

    How a Parashock looks like. With the big cap jewel and integral shock spring retainer assembly in place.
    Miyota Parashock.jpg
    The cap jewel is a flat and thick high grade ruby which can be considered as a real gem in the sense. This is one feature you can brag about.

    The cap jewel removed and the spiral spring jewel bearing holder is shown. You can even see the tip of the balance staff. This compensates perfectly for lateral shocks and very efficient. My father and I never encountered broken balance staffs having this design.
    Miyota Parashock 1.jpg
    This design was, I believe, pioneered by Erismann-Schinz Ltd. of Switzerland and was employed on several Swiss movements. During that time Incabloc, Kif and other shock protection system dominated the Swiss movements market.

    The Miyota Parashock in detail, a two-piece shock protection system.
    Miyota Parashock 2.jpg
    Together with the sleeves in the balance bridge and the main plate that arrest the bigger shoulders of the balance staff, the ends of the staff pivots are isolated from the weight of the entire balance wheel protecting them from undue stress.

    I haven't seen the first models of the calibers but I think Miyota (Citizen) was already using them for quite sometime. I have another Miyota caliber, a beautiful manually wound caliber 0201 which was a predecessor to the caliber 82xx series.

    Caliber 0210.jpg
    Citizen New Master.jpg

    Brief specs:
    Manual wind
    18,000 vph
    21 jewels
    Central sweep second wheel
    Parashock
    Last edited by JunMel; 02-18-2011 at 08:19 PM. Reason: Caliber number correction on Miyota 0201
    Tempus fugit...

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