Using an existing anchor to make a replacement.

Discussion in 'Clock Repair' started by shimmystep, Aug 23, 2017.

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  1. shimmystep

    shimmystep Registered User

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    #1 shimmystep, Aug 23, 2017
    Last edited by a moderator: Dec 15, 2017
    I've created this this post due to a recent post enquiring around making replacements for worn anchors. Hope it helps anyone thinking of doing that, who has not tried it before.

    Wear ruts on the impulse faces of an escapement anchor are common place. Sometimes it is possible to move the position of the anchor on its arbour, to introduce unworn areas to the pathway of the escapement wheel teeth. However this may have been done before to the anchor, or the ruts are in a such a place that rules out the use of any unworn area on the impulse face. For example, if the ruts are dead centre of the faces, there may not be enough room for the escapement teeth to land fully, either side of the ruts.

    Gauge plate tool steel is an ideal material to use to fabricate a new anchor. It is well made to precise thickness and hardens well. The gauge plate below is O1 steel, chosen to fabricate a replacement anchor from an English long case movement. The original anchor had already been repaired historically at some point by grinding down the entry pallet and putting a steel slip on the exit pallet. Neither operation had been done well, and the geometry of the anchor was terrible so I decided to replace.
    xyzzytom_354534

    A hole to allow the anchor arbour to fit snugly through the gauge plate needs to be drilled. Blue the gauge plate but leave some areas unblued where the anchor will sit, to accept the superglue. The anchor can then be super glued to the gauge plate. When it has dried, scribe with a hardened steel sharp scribe accurately around the original. The scribe line will also need to make an impression in the steel itself not just the blue. I use a blue Sharpie pen to blue colour the steel, as I find the engineers blue ink a bit messy.
    xyzzytom_354539


    If you need to use a brass collet to mount the anchor, as in this case, the hole needs then to be enlarged to suit.
    314268.jpg

    Now the task of removing excess steel can be done. A combination of saw, mill and files are ideal. Not having a mill does not stop the ability to make these at all. I have made many without a mill, before I bought one. Using a large half round file is the way to go for the underside profile of the anchor. Choosing the right shaped file will go a long way to a good shape and finish when trying to recreate a period style.
    314269.jpg 314270.jpg 314271.jpg

    Once all the excess is removed and you have the basic shape and style you want, you can move on to the impulse faces. If you have taken excess steel off up to the scribe line, and not through or over it, you will have left yourself material for fine adjustments. The anchor will come on and off the arbour numerous times when you are adjusting the impulse faces, as you will need to keep replacing it in the movement and testing its geometry with the escapement wheel. i.e. adjusting the drop off edges and span.

    Below, the rough impulse face is being made on the mill, however, as mentioned this can be carefully filed with the right technique. You can take steel off, but you can't put it back on! Take a little and test again, take a little and test again.
    314276.jpg

    When you are happy with the drops and span, which should be the same as your original anchor if you have scribed and removed steel well, you can then put a finish on your impulse faces. Folk have different techniques to do this. Personally I work up from 1500 grit wet and dry paper all the way through to 7000grit wet and dry, and then finish off with a felt wheel and fine polish.

    However, that said, I finish off the impulse faces to 2500 grit and then harden the anchor ends (or the whole anchor) and complete the final finish after hardening. Heat until cherry red for approx 20-30 seconds before quenching in either oil or water. In this case oil, given it is O1 steel. Personally I do not trust that because the steel has been cherry red that the steel has reached and maintained the appropriate temperature that will enable hardening at quenching. I have made that mistake before. Personally I always test the steel with a small magnet, if the steel is no longer magnetic, it is ready to be quenched/hardened. A change must occur, where the carbon in the steel must change from carbon pearlite form to a martensite form, which will enable hardening. The magnet test will tell you if this has been accomplished.
    When quenching the anchor in oil, move it about in the oil as you do so.

    Oil quenching steel, I find, leaves less scale on the piece and is easier to remove in my experience. The reason I only finish the impulse faces down to 2500 grit before hardening, is because I find that 2500 grit is the finest grit I can get away with using to remove any scale. After this has been removed the anchor can be tempered in order to make it less brittle but still maintain hardness. Most domestic ovens will go to approx 240 deg centigrade (about 464 F), and tempering at that temperature in the oven for an hour is good enough. The steel should appear straw coloured after this. That colouration is easily removed with fine paper.



    When you are satisfied that the anchor ends or the whole thing is hardened and tempered, then finer and finer grades of wet and dry can be used to finish the impulse faces, followed by a felt polishing wheel and fine polishing compound. I use Menzerna yellow super finish. With a felt wheel, this will give a mirror finish.
    314283.jpg

    The desired final finish to the main body of the anchor can be completed and refitted to the arbour, or re-fitted via a brass collet on the arbour. I only harden the ends of long case anchors, in order that in the future a repairer can easily adjust the span if they need to remove surface area from the pallet impulse faces due to wear, with out fear of snapping it when they close the span.

    314287.jpg 314285.jpg 314268.jpg 314269.jpg 314270.jpg 314271.jpg 314276.jpg 314283.jpg 314284.jpg 314285.jpg 314287.jpg

    314268.jpg 314269.jpg 314270.jpg 314271.jpg 314276.jpg 314283.jpg 314287.jpg 314285.jpg 314268.jpg 314269.jpg 314270.jpg 314271.jpg 314276.jpg 314283.jpg 314284.jpg 314285.jpg 314287.jpg
     
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  2. bruce linde

    bruce linde Technical Admin
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    hmmm... kind of like watching a great guitar player solo... **i** couldn't begin to play it, but can sure appreciate how good it is! :)

    thx for sharing info, techniques and experience... very informative and helpful.
     
  3. R&A

    R&A Registered User

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    So did it work. Looks good
     
  4. shimmystep

    shimmystep Registered User

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    Thank you :)

    It is happily working away in a customers clock.
     
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  5. shutterbug

    shutterbug Moderator
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    Nice tutorial, shimmy! :thumb:
     
  6. roughbarked

    roughbarked Registered User

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    Yeah. Templates are good.
     
  7. AJSBSA

    AJSBSA Registered User

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    #7 AJSBSA, Aug 23, 2017
    Last edited: Aug 23, 2017
    Great work shimmy and tutorial, I would only add that gauge plate is extremely rough on tooling when I made my own longcase clock anchor I avoiding using machine tools altogether it can be done with just a pillar drill with a carbide PCB drill, piercing saw and files

    314306.jpg 314307.jpg
     

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  8. shimmystep

    shimmystep Registered User

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    Thanks for the nice feedback :)

    Stephen, nice anchor, good work.
     
  9. David S

    David S Registered User
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    Very nice work Shimmy and I like the references to being able to do this stuff without fancy equipment. I think that helps the beginners here that wonder how they can get from "here to there", as they progress.

    Also very nice photos as well.

    David
     
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  10. shimmystep

    shimmystep Registered User

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    Thanks David. A great many things can be done without the equipment I believe, it might take some creative thinking and more time but it can be done. I also think that by doing as much as one can without equipment, it means you use and develop hand tool skill, it did for me anyway.
     
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  11. wow

    wow Registered User
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    That's where I am also, David. Well said!

    Thank you, Shimmy. As always, great work and another great tutorial.
     
  12. shimmystep

    shimmystep Registered User

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    Thanks Will. These can be made with only files, saws and patience :)
     
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  13. ClipClock

    ClipClock Registered User
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    Great tutorial Shimmy, hopefully the mods will find a way of pinning it somewhere so it can be found easily when needed!
     
  14. P.Hageman

    P.Hageman Registered User

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    Wow, thats the right way of doing!! Perfect finish on the faces, must be working very good. Thats what I call restauration. Thanks for showing Shimmy.
     
  15. Berry Greene

    Berry Greene Registered User

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    Great tutorial and comments too. Getting a result within ones resources IS engineering IMHO. Using one's ingenuity. I wonder sometimes where the balance is between appearance and function. Surely in the case of a clock ….. it seems at first obvious. Yet I just passed a photo from AJSBSA with fantastic wow factor. So aesthetics can't be ruled out. Once seen there's no going back. I have an anchor to make. Mmm!
    BerryG
     
  16. bangster

    bangster Moderator
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    Done. See Hints & How-To's forum
    bangster
    moderator
     
  17. daveR

    daveR Registered User
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    This is a good one shummy, I have to do one so it is timely that it has come to the top again. one question: having got your besutifully flat impulse facesfrom the mill, how do you go about keeping them that way through the polishing processes?
    David
     
  18. novicetimekeeper

    novicetimekeeper Registered User

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    Great to see Sally still helping out. I have a bell in the conservatory I was going to send to her, think of her every time I see it!
     
  19. bangster

    bangster Moderator
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  20. novicetimekeeper

    novicetimekeeper Registered User

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    Clipclock. The one you were replying to in #16. Sadly no longer with us but fondly remembered.
     
  21. MartinM

    MartinM Registered User

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    O1 is usually sold in an annealed state. But not always. Make sure before you start trying to mill it.
     

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