Home Forums General Discussion Forum Mainspring Let Down

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      Firstly I apologise for any dumb questions, I am a complete novice and just finding my feet!
      Could anyone tell me how to let the mainspring down on a 3/4 plate Oris pocket watch? I have worked on 5 or 6 other watches/pocket watches where I could see or locate the click but on this watch I am at a loss. It seems on Elgins and others there is a hole at the one o’clock area where the click can be released but I can’t see it on this watch. I have scoured the internet but not found anything.

      The other issue I have is that I seem to be unable to find a let down tool small enough for the watches I have (I am in the UK by the way!) I have purchased a “bunch” of 14 keys and then a wrench but none of these fit into the Waltham, Oris or other miscellaneous makes I have purchased to practice on. I haveseen the list of suppliers for the UK on another thread on this forum and will be looking at them this evening but if anyone has any suggestions it would be appreciated.

      Bob Tascione

        Hey Andy, no such thing as a dumb question up here. Ask away.
        Also Welcome to the Forum Andy!
        Might be able to help on the letting down mainspring question but not sure what movement you’re dealing with. Would it be possible for you to put a few pics of the movement up here? That will probably do the trick.

        As for the let down keys have you tried Uncle Larry’s in Canada? You can find him really fast by putting ‘Uncle Larry’s watch parts’ into the big ‘Gs’ search engine. Another alternative is to make some quick let down keys by measuring the stem square dimensions. You can make one up quickly using a round piece of steel or brass stock inserted into a pinvice and then filed square to the required dimensions.

        Take care for now,


          Hi Bob, the movement is an Oris Cal 421, 7 jewel. I’m sure I am missing something basic!! Will post a pic when I work out how to do it!!

          And thanks for all the info on the tools – it was really helpful.


            Sorted now, as I thought, I was missing something basic!! Thanks for the reply though and apologies for wasting your time!!

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