Repivot a Balance Staff/Graver Sharpening - Part 2

Поділитися
Вставка
  • Опубліковано 22 сер 2024
  • Process of completing the initial Staff Pivot. In includes Graver Sharpening
    / @jdrichard

КОМЕНТАРІ • 11

  • @ferguscosgrave7510
    @ferguscosgrave7510 Місяць тому +1

    Iam enjoying looking

  • @mercuriall2810
    @mercuriall2810 Місяць тому +1

    Great work, JD! This isn’t an easily accomplished task.
    That brass graver sharpening jig looks fantastic, similar to a crocker style jig, but a better design. Perhaps you could make an insert for it so it can grip the narrower knife shaped gravers?
    The translucent white stone you showed is a very hard, fine grit Arkansas stone. The ruby red coloured one is a composite ruby stone.
    Regarding parting off, my preference would be to seat the balance onto the new pivot and then part off immediately, just as you did.
    There’s no right or wrong graver shape to use for parting off in this instance, but the thin knife profile gravers are great for this task. A knife edged file is often great for parting off, too.
    One tip regarding Loctite, which will make your bottles of it last far longer and have it perform more reliably :
    The chemical process by which loctite begins to harden is activated by the liquid coming into contact with metal.
    Once that reaction starts, it continues even in the absence of metal.
    To preserve your loctite and keep it in optimum condition, always dispense some loctite from the bottle onto something non-metallic. I often use a little bit of cardboard.
    Then transfer the loctite on the cardboard onto the part where you need the loctite.
    If you dispense loctite directly onto the metal part, the chemical reaction to harden it starts. If even a tiny bit of ‘activated’ loctite gets back in the bottle (it does), then that bottle of loctite slowly starts going bad and won’t perform to manufacturers specifications.
    In extreme cases, using it from the bottle onto the metal part will result in the rest of the product hardening inside the bottle.
    The loctite manufacturers don’t advertise this fact widely, because they sell heaps more loctite if people use it right out of the bottle.

    • @JDRichard
      @JDRichard  Місяць тому

      Great tip on the Loctite. As well, I knew that the white one was the Arkansas Stone, but I wasn’t sure what the red one was. I can remove more material using the ruby coloured one and then do the fine work with the Arkansas stone. I’ve use these two stones for many years to finalize pivots. I usually use synthetic 0W 20 oil on the stone, and not cutting oil

    • @JDRichard
      @JDRichard  Місяць тому

      I do have to go to the cottage for the next few days so I won’t be doing much watch work after lunchtime today. 27 days of retirement so far and I haven’t killed myself. I do need to go and jump on stage and start jamming.

  • @sonnymoorehouse1941
    @sonnymoorehouse1941 Місяць тому

    Fantastic video !!!!
    Gold Jerry Gold !!!!
    Interesting sharpening. love your sharpening jig.
    and you sharpen dry ?
    Ive always used 3in1 oil.
    are you going to use those pivot doming tools ?

    • @mercuriall2810
      @mercuriall2810 Місяць тому +1

      The closer the new pivots get to the final diameter, the more risk of snapping them off whilst reducing them in the lathe.
      Getting below 0.1mm on the lathe using a freehand graver is very difficult for all but the best. 0.15-0.2 is a safer place to stop.
      The final adjustment of the pivot to the correct diameter is done with a pivot file on the Jacot lathe, and the last couple hundredths of a mm is removed/compressed by burnishing on the Jacot tool.
      At this point you have a highly polished and well hardened pivot, but it is flat ended. This is fine for pivots that don’t run on endstones, but a balance staff pivot needs rounding off once it is the right length.
      The Jacot tool lantern runners are for shortening and rounding the ends of pivots, the shortening is done using the lantern, but the pivot doming tools you mention are an easier and safer way to round off the tip if you don’t have heaps of practice doing it in a Jacot tool.

    • @JDRichard
      @JDRichard  Місяць тому

      @mercuriall2810 i’ve actually finished pivots off in the lathe using an Arkansas stone versus a pivot file, to get the pivot down to almost the right diameter. Then I use the burnishing part of the pivot file to finish off the pivot. I’ve done this before and shown it in other videos, and it works really well, I’m also able to round off the pivot well still in the lathe. If I have to do further shortening or sizing of the bounce staff, then I go to the jacot tool. The challenge here will be determining the overall upper and lower length of each of these new pivots. I can kind of see where I cut off the old pivots so I can get very close, but what I’d really like to do is have the inner length of the complete balance staff. This of course is very difficult to measure between upper and lower jewel settings. And may end up being a trial and error exercise. I don’t want to cut it too short because you can’t grow a balance from nothing

    • @mercuriall2810
      @mercuriall2810 Місяць тому +1

      @@JDRichard Bringing the pivot down very close to final diameter using an Arkansas stone is certainly an equally valid way to do it, if you can keep the pivot cylindrical.
      The beds of the Jacot tool are great for keeping things cylindrical, but nothing wrong with using a stone as you did if you prefer.
      Burnishing down on the Jacot tool to reach final size very last bit is important, though. It’s the compression of the pivot between the burnisher and Jacot tool bed that hardens the outside of the pivot and gives a highly polished, friction free bearing surface.
      This last step can be done on the lathe rather than the Jacot tool if you have a Jacot bed to fit your tailstock to rest the pivot in.
      An equally smooth finish can be had via sapphire burnisher on the lathe without a Jacot bed to rest the pivot, but you don’t get the hardening that burnishing the pivot in a bed provides.
      In future, I’d strongly suggest final finishing all new pivots be done on the Jacot tool, or Jacot beds in your lathe tailstock. You can still burnish the pivots of this staff on the Jacot tool now to harden them.
      There’s an excellent PDF circulating online that shows really high magnification of pivots finished in different ways. Burnishing in the Jacot tool/Jacot bed tailstock provides a far superior finish. If I can find a copy, I’ll email it to you.

    • @sonnymoorehouse1941
      @sonnymoorehouse1941 Місяць тому +1

      If you have a piece of wire thin enough to fit into pivot jewels you can install balance cock with cap jewel removed and place wire down through pivot holes resting it on lower cap jewel. Then use a scribe to mark top of wire flush with hole jewel. It will give you a really close total hight of staff pivot to pivot.

    • @JDRichard
      @JDRichard  Місяць тому +1

      @sonnymoorehouse1941 Not a bad suggestion.