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  • 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, 08:19 PM. Reason: Caliber number correction on Miyota 0201
    Tempus fugit...

  • #2
    Very similar to the movement HMT used...

    ...in their military-style Pilot watch. It is well known they use Miyota technology:


    (borrowed photo above)

    My watch:


    Thanks fo the info, JunMel!

    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 0210 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
    Time is Money, except on Dark Side of the Moon

    Comment


    • #3
      You're most welcome, Brad. That's a very nice HMT model too. And its the first time I've seen that caliber in a different brand. It's no surprise why some watch manufacturers opt to use some Japanese calibers. Better build, better quality like the Swiss does and you won't find it in cheap knock-off movements.

      It's nice to have the old manuals, they give nice finger exercise and you feel united with the movement everyday
      Tempus fugit...

      Comment


      • #4
        Thanks for the pics and info!!! Very cool!

        Comment


        • #5
          Thanks! I was lucky--a colleague from India travelled home and found about 5 new mechanical HMTs at his local shop. He brought them back to the States and gave me a pair. The other is a 21j automatic day/date (very Rado-like!). Combined, the prices for these 2 watches amounted to less than I would expect to spend on cheap leather straps.
          Cheers,
          Brad

          Time is Money, except on Dark Side of the Moon

          Comment


          • #6
            Great post!

            I wonder if the asymmetry of the spiral spring design is why others have avoided using it. The other systems seem to use more symmetrical spring designs.
            -Brian

            Comment


            • #7
              Great post! I have newfound respect for Citizen/Miyota.
              sigpic

              Comment


              • #8
                very cool post

                thank you

                Comment


                • #9
                  Thank you all guys. I will try, in my capacity and with your approval, to post what we think are very innovative designs employed in watches. I was thinking of comparing features between watches but I don't wan't to upgrade or degrade a feature of any watch let us just give them credit. But this credit I will never give to fakes as those makes me lose my appreciation in the art of watchmaking. I will try my best not to duplicate posts already documented before, and please bring it to my attention just in case.

                  I will go back in time again when I saw some admirable designs that amazed me, baffled me, made me wonder, specially in the movements. Tiny products of engineering that made the time go round. Pity I never thought of photographing them during those times. If I can get hold of them once again I will post them for all of us to see, understand and enjoy. I am hoping to get a better camera with a strong macro feature so we can all see the finest details.
                  Tempus fugit...

                  Comment


                  • #10
                    Originally posted by FuzzyB View Post
                    Great post!

                    I wonder if the asymmetry of the spiral spring design is why others have avoided using it. The other systems seem to use more symmetrical spring designs.
                    Hi Brian. My father commented on the original Swiss design which was somewhat a true spiral. He told me that though it was the brightest idea he had seen, he observed that it was not so stable considering the weight of the screwed balances employed before. I can imagine the gyroscopic effect he was pointing out. He claims there could be an undue wobble in the spin of the balance wheel since the first design was not stiff enough to maintain the axis of rotation. According to him whenever he touches the rim of the balance wheel lightly with a tweezer he can feel a very lenient springing action. There could be some offseting if the watch is in any side position. Maybe we can't observe that when it is in a dial up or dial down position. With the Miyota design, I have to apply a slight force approximately equal to the weight of the balance wheel before I can feel a springing movement. It could already be considered and redesigned by the engineers.

                    Cheers!
                    Tempus fugit...

                    Comment


                    • #11
                      Miyota 8215

                      A Company named HEMESS in Glashütte, Germany, use the Miyota 8215 in their watch "Hematic Royal", but they put in a lot of their own parts and do a very nice finish. Have a look at these watches JunMel if you have the time and tell me what you think.
                      Regards to all from the Vienna Woods
                      Peter

                      Comment


                      • #12
                        Those are nice remakes of the Miyota, Peter.

                        I was so surprised at what these movements can be, given proper attention; gilding, engraving and such. 8215 is a date only version of the more popular 8200A, chosen mainly for diver's watch application since it has thicker bridge and rotor and maybe the plate too. According to an agent, it was made that way to compensate for tremendous pressure applied on the watch in the deep. Quite logical, and considering that the bridge is one piece, it is robust in construction omiting few screws on ratchet wheel and barrel wheel. Not to mention the complete omision of automatic mechanism bridge and screws. Assembly is surprisingly easy and one won't have to fiddle with the pivots.

                        Miyota maintains very critical clearances on the shoulders of the pivots to the jewels, that an undue pressure on the bridge of the thinner 8200A can put all of the wheels to a halt.

                        I wish to see decorations too on the main bridge and the rotor. I got an idea from Brad when I was directed to his site detailing Benzinger's work on his re-cased Elgin. Excellent work and a unique idea.

                        Regards,
                        Jun
                        Last edited by JunMel; 02-18-2011, 08:16 PM.
                        Tempus fugit...

                        Comment


                        • #13
                          Hi,

                          Although the thread is rather old, I felt it would be the right place to ask my question.

                          I have a 10 years old Citizen 7 watch with a Miyota 8200 movement. While visiting my home town I decided to get it serviced as it was not accurate anymore. A local watchmaker opened it up and told me that the oil has dried up and the mechanism needs striping down, cleaning and reassembling. The work was going to take several weeks therefore I asked my dad to send the watch to me once it has been serviced.

                          Without meening anything bad my dad did what he was asked to. He got some bubble wrap, wrapped around the watch, stuck in a bubble-padded envelope and posted it to me. Imagine my horror when I found that my precious watch was delivered through the letterbox and landed on the floor!

                          The bubble wrap took some of the impact. However, I am seriously worried that the 3 foot fall has seriously damaged the mechanism inside. So far it seems to be ticking away nicely, but what can be done to make sure no damage was done?

                          Best regards,
                          Martynas

                          DSC_7273.jpg
                          Last edited by mbrijun; 09-15-2012, 04:00 AM.

                          Comment


                          • #14
                            If it is running well and keeping time then I would relax. It is probably all ok.
                            DavidM1

                            Comment


                            • #15
                              I'm surprised to see a resurrected old post

                              Hi Martynas, David is right, if it ticks it works BTW, that's a neat Citizen "Eagle" 7.

                              Well, I am not in any way connected to Citizen but I do collect some nice models. And being a watch technician here in my place I have discovered that little feature of Citizen that is not offered by any other watch brands, including the most expensive watches: the unique Parashock system.

                              If you are paranoid that your Citizen incurred a damage from a 3-foot fall, surely it survived that drop specially it is still wrapped in a bubble bag. I can't find the documentation that I've read before but true to Citizen's claim the Parashock survived the most abusive fall that ever occured. Actually a prototype of a Citizen watch with the Parashock system was dropped (in a packaging) intentionally from a helicopter at a height of about 20 meters or more (it was documented by media). It can be considered a torture test for a precision machine but it survived without any damage whatsoever. Hence, the Parashock system is still employed exclusively by Citizen/Miyota till these days.

                              Cheers!
                              Last edited by JunMel; 09-15-2012, 11:21 PM. Reason: Rectified ambiguity.
                              Tempus fugit...

                              Comment

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