Home Forums General Discussion Forum waltham friction fit balance

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  • #49405
    mclark3617
    Participant

      I replacing the balance pivot on a Waltham pocket watch, its a friction fit. When I first installed just the pivot a while ago and set it aside. Now that I have time to work on it again I notice the shaft is loose, it seemed to press in when I first installed it, now it slips in and out with ease. Question I have is am I suppose to tap it a bit to seat it in the taper? Or am I gonna have to peen the pivot shaft a bit to get it to press in better. And yes, I’m sure its a friction fit balance.

      #61314
      chris mabbott
      Participant

        @Mclark3617 wrote:

        I replacing the balance pivot on a Waltham pocket watch, its a friction fit. When I first installed just the pivot a while ago and set it aside. Now that I have time to work on it again I notice the shaft is loose, it seemed to press in when I first installed it, now it slips in and out with ease. Question I have is am I suppose to tap it a bit to seat it in the taper? Or am I gonna have to peen the pivot shaft a bit to get it to press in better. And yes, I’m sure its a friction fit balance.

        Any chance of a photo so we can be certain of what is what? To be sure is to be sure :)

        #61315
        Bob Tascione
        Moderator

          Hi MClark,
          Peening won’t work with this type of staff since there’s no rivet to peen. When pressing that Waltham staff you do need to tap it until the top of the bevel on the staff is level with the top of the blue hub. The bevel tapers on the staff do need to make contact and seat. Doesn’t usually take much and you should ‘feel’ when it’s bottomed out and seated.
          Hope this helps,
          Bob

          #61316
          mclark3617
          Participant

            Thanks guys, and ill get a pic posted soon. So its normal for this to slip up to the taper then tapped into the tapper? cause of that didn’t work I was just gonna tap a few flats on the pivot just to knock up enough material to give me more of a light press.

            #61317
            mclark3617
            Participant

              Pic as promised

              #61318
              Bob Tascione
              Moderator

                Hi Mclark,

                So its normal for this to slip up to the taper then tapped into the tapper?

                I’m not sure about when the pressfit begins as it’s been a while since I replaced one and don’t have one in front of me to try. The press fit is light and should be around .005mm to .01mm so it’s possible that you have a staff that’s out of tolerance but by tapping it in place you’ll know for sure. If it is a bit undersized then rolling it between two small flat needle files should strike up a light knurl around the entire circumference for a decent press fit.

                Bob

                #61313
                mclark3617
                Participant

                  Good idea, never thought about using a file as a knurlng tool. Thanks Bob

                  #61320
                  Bob Tascione
                  Moderator

                    You’re welcome Mclark,
                    Of course the best and correct option is to grab another staff that fits without altering it this way but if that’s not possible then the knurl will at least give grabbing power.
                    Still a good chance that tapping it in the rest of the way will do the trick.
                    Good luck,
                    Bob

                    #61319
                    chris mabbott
                    Participant

                      Thanks for the photo. I just wanted to be sure for my own sanity before commenting, but now that I have self confirmation…. Yep to what brother Roberto said 😆

                      Some people herald the friction fit staff, but others, myself included, have seen their failings. Like anything that is taper fit, friction, after a few re-staffing jobs, the original hole expands, the result is a not quite tight fit as when new. I have a waltham service buletin somewhere that recommended replacing the complete balance after three staff changes.

                      Your’s could have fallen into this category, no one knows how many staffs it has seen. Broken pivots were the main failure back in the day, due to knocks, so depending on the age of your watch, at least, minimum, it has had two replaced already :?:

                      Here’s an interesting little something, you may find it useful… :)

                      #61321
                      chris mabbott
                      Participant

                        A question about your Waltham, mostly for a little study I’m doing, and curiousity, would it happen to be either a model 1899 or 1908 16s or 12s ? Could you also tell me what year it is please..

                        Thx in advance

                        #61322
                        Bob Tascione
                        Moderator

                          Hey Chris,
                          I’m glad you put that diagram up here. It jogged my memory. :) Mclark, as his diagram shows, the taper shoulder fits down into and just a little below the hub surface and not level with it like I said earlier. The tool they show in that diagram may not be in your staking set but no worries as a common round nosed punch will also work for taping it down into the hub recess and is commonly used. Again you’ll feel when it’s seated. Also having a small selection of friction square shoulder and taper shoulder staffs (such as the 4860 & 4861) can be helpful as you’ll find a small variation in diameter between them and can use one that fits best. At todays staff prices this may no longer be an option. In the past staff assortment prices were reasonable and many watchmakers had vials filled with the most common balance staffs so picking through them was common procedure. I’m not sure which staff you are using but as an example the 4860 and 4861 are very common staffs and extremely easy to replace and when done correctly poses little danger to balance wheel distortion or balance wheel hole damage that can occur with riveted type staff removal and replacement when done incorrectly. If the hole is too far gone as Chris suggests may be the problem then replacing the hub (or balance if no hub is available) or making a new staff may be your only option. Still may get lucky though when you seat it down the rest of the way.
                          Good luck Mclark and please let us know how it goes,
                          Bob

                          #61323
                          mclark3617
                          Participant

                            For info,, this is a 14s Waltham Bond st. grade model 1897 brass 7 jewel production year is 1915
                            it also looks like the pivot holes on the second hand wheel need to be bushed.
                            and my notes say its a 8143 Balance Staff
                            the old staff friction diameter is .722mm(.0285)
                            the new staff friction diameter is .709mm(.0279)
                            Im gonna try the file knurl idea

                            #61324
                            mclark3617
                            Participant

                              The knurliing idea didn’t work for me but I was able to find another balance and the staff fit fine in this one. so the problem must be in my old balance…

                              #61325
                              chris mabbott
                              Participant

                                Thanks for the info bud. The new balance you found ,was it from another watch of the same ilk? Do you have the original hairspring and roller that cam with the replacement balance wheel?

                                Just checking, but you know that you’ll have to re adjust and sync the complete balance if you swap or interchange the parts? 😮

                                #61326
                                chris mabbott
                                Participant

                                  I forgot to mention, there is one other thing you can try, we’ll, two really.. Preferred method is to make another staff that fits, or to have someone make a slightly larger one for you.

                                  The other way, is you could use a hole closing punch on the top of the balance hole to try and reduce the diameter a mil. You won’t need much for an interference fit. But you have to be veeeery careful not to distort the arms.

                                  At least that way you can keep the original matched & numbered balance..

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