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The Miyota Parashock

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  • #16
    Hi David, JunMel,

    thank you for reassuring me, your advice makes me feel better. Still, I should have known better and foreseen this happening!

    I am a little confused about one thing though. It looks like the Parashock protects the balance (in my understanding that's the little flywheel that goes back and forth and counts the seconds). Now the heaviest part in an automatic watch would be the balast that winds up the watch. In any fall situation surely that would be the most likely candidate for a damage?

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    • #17
      Hi Martynas. You are referring to the winding rotor. It is mounted on a miniature ball-bearing with a single but big screw as in the case of your Citizen 8200A. It swings as you move your wrist causing it to wind the mainspring barrel. It winds in one direction and spins freely in the other. Sometimes you will feel a little whirl when the rotor is freewheeling, but this is normal. In a droppage it won't get dislodged if the watch technician tightened the screw properly. It gets worn-out only in an event of water entry. The rim of the rotor rusts and the ball bearing clogs or wears out. You can check yourself by shaking the watch vigorously. If you hear or feel a rattling sound like metal banging against metal or grinding sound (not the jerking sound of the rotor bearing) then either the rotor is loose or the bearing is worn. Other parts can also get damaged if the bridge screws are not properly tightened. Else, the entire movement is literally safe from droppage alone. The factors that can ruin a movement are: 1) water entry, 2) dried out lubrication, 3) worn-out pivots/bearings/wheel teeth, 4) subjecting to strong magnetism 5) loose screws, 6) noob technician induced damages, etc.

      The balance staff is the most delicate part of a watch movement so research and development was conducted intensively to find a solution to protect it. Among the best designs developed is the Parashock system. Other parts are considered robust so no need to worry on those.

      While we're at it, I have drawn a diagram with AutoCAD this morning, since I can't find a decent diagram in the net, to help explain the action of the Parashock system.

      Citizen-Miyota Parashock 1
      Parashock Action.jpg

      Best regards.
      Tempus fugit...

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      • #18
        Hi JunMel,

        thank you for taking time to draw a diagram. Initially I thought that protection is only available for axial movement, but thanks to your picture I understand this is not the case.

        When I swing the watch and then listen to it, the winding rotor makes the whirring sound which eventually turns into little clunks and then stops. Like this:

        whir-whir-whir-clunk-whir-whir-clunk-whir-clunk-whir-clunk-clunk-clunk

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        • #19
          That sound indicates everything is normal I have a big 35 years old Citizen dive watch (53-2273) given by a retired military which he named 'Black Thunder' due to that familiar '8200' sound whenever he brings it near his ear. For more than 30 years of operation, the caliber 8200A inside is still like new and the timing is as accurate as a Rolex Submariner. It is really hard to part with 'characters' like this

          Kind regards,
          Jun
          Tempus fugit...

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          • #20
            Thanks for the info.

            Iīm an Citizen 8260A user. It still in perfect conditions and works incredible right, I donīt change it for anything.

            Cheers!
            Last edited by fran1080; 12-13-2012, 08:06 AM. Reason: Very similar to the movement HMT used...

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            • #21
              Thanks for the info.

              Iīm an Citizen 8260A user. It still in perfect conditions and works incredible right, I donīt change it for anything.

              Cheers!


              Originally posted by JunMel View Post
              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:
              [ATTACH]6996[/ATTACH]
              * 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.
              [ATTACH]6997[/ATTACH]
              * 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.
              [ATTACH]6998[/ATTACH]
              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.
              [ATTACH]6999[/ATTACH]
              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.
              [ATTACH]7000[/ATTACH]
              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.

              [ATTACH]7001[/ATTACH]
              [ATTACH]7002[/ATTACH]

              Brief specs:
              Manual wind
              18,000 vph
              21 jewels
              Central sweep second wheel
              Parashock

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              • #22
                Does anyone know if the 8260A is still made? And if so, where I can source them from?

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