JUF Lunar

Discussion in '400-Day & Atmos' started by etmb61, Aug 30, 2018.

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  1. etmb61

    etmb61 Registered User
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    This arrived today. Lots of corrosion so it's apart now for restoration. The drum has lost a good amount of its plating and I need to get a back cover for it. I also need to replace the paper dial as it's falling apart.

    As you can see it has the DRGM stamp on the movement, but no other markings. The suspension bridge is adjustable to set the beat, a nice surprise.

    Can't wait to see it run.

    Eric

    L1.jpg L2.jpg L3.jpg
     
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  2. KurtinSA

    KurtinSA Registered User
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    #2 KurtinSA, Aug 31, 2018
    Last edited: Aug 31, 2018
    Nice one! You are amassing a unique collection of clocks!

    It looks like clock #79 in the repair guide, but the back plate reference isn't the same as your plate. I don't find that back plate in the guide. The patent number wasn't listed in the report Doug Stevenson wrote for the bulletin many years ago. But the placement of the number would indicate that the patent was awarded sometime in 1913.

    Kurt
     
  3. etmb61

    etmb61 Registered User
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    Kurt,

    This one wasn't on my wish list. I was saw it online and managed to get it at a good price.

    John Hubby has posted a few times about the plate markings and dates for these. The DRGM was awarded in 1914, so this is one of the earlier examples. The suspension bracket and pendulum are different than the later versions.

    Do you have the reference handy for that bulletin article?

    Thanks,
    Eric
     
  4. KurtinSA

    KurtinSA Registered User
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    Eric -

    I only found out about the work done to find the DRP and DRGM patents relating to 400-day clocks after reading some of the Torsion Times. I found the article by doing a bulletin index search for "DRGM". It shows up in Vol 48 Iss 360 Pages 33-45...looks like February 2006.

    Kurt
     
  5. etmb61

    etmb61 Registered User
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    That's DRGM 588490 (for the search engines).
     
  6. KurtinSA

    KurtinSA Registered User
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  7. etmb61

    etmb61 Registered User
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    Thanks Kurt,

    I think I've read all the lunar clock threads on the board by now. There isn't much there.
     
  8. etmb61

    etmb61 Registered User
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    #8 etmb61, Sep 1, 2018
    Last edited: Sep 1, 2018
    Here are some detail pictures of the movement. I won't be taking It apart at this time. It has a damaged pinion on the second wheel that I cannot repair. For now I'll just finish cleaning it up and put in on display.

    The plates are about 59mm diameter and 1mm thick.
    Back_plate.jpg Front_plate.jpg
    The bracket looks like it's fixed but it is adjustable. The cannon pinion and hour wheel float on a fixed center shaft, with the minute wheel driving the hands.

    Escapement.jpg
    Here you can see the pin pallets, and the beat adjustment joint on the suspension bracket.

    W1.jpg
    Here is the 1st wheel the click and ratchet attached.

    W2.jpg W2_wear.jpg
    Here is the 2nd wheel with a solid brass pinion. All the other examples I've seen have lantern pinions throughout, so I was surprised to find this. The leaves are almost worn through, so I'll be leaving this one alone for now.

    W3.jpg
    Here is the 3rd wheel showing the tension spring under the minute wheel.
     
  9. Harry Hopkins

    Harry Hopkins Registered User
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    #9 Harry Hopkins, Sep 1, 2018
    Last edited: Sep 1, 2018
    Thanks for the pictures Eric. I am surprised to see a brass pinion.. especially on a second wheel. Also surprised to see an open mainspring. Are the main wheel teeth ok?
     
  10. etmb61

    etmb61 Registered User
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    The teeth that mesh with the brass pinion are worn on the driving sides. They resemble saw teeth now. The rest of the movement looks good.
     
  11. etmb61

    etmb61 Registered User
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    Here is the case. I thought I'd done a good job cleaning it up until I put it under bright lights and took its picture and all those dark spots showed up.

    Case1.jpg Case2.jpg Case3.jpg
    Everything visible is brass except for the top drum which is ferrous. The front bezel is also brass.

    Case_bottom.jpg
    The base has a ferrous doubler plate. You can see from this picture that the columns are evenly spaced around the base. All but one other I've recorded have the front 4 columns in a rectangle centered on the base and the 5th column centered on the back. The small Vosselers also have the columns evenly spaced but use a different base. See clocks 79 and 80 in the repair guide. Also, this case is only 9 1/2 inches tall. Clock 79 (Horolovar Collection 42) is 10 1/2 inches tall.

    Column_parts.jpg
    Here are the parts for the columns. The center rod is basically a long threaded nail.

    Column_bottom.jpg
    The bottom of the column is open and fits over the center of the base thimble.

    Column_top.jpg
    The top of the column has a pressed in cap that keeps it in place around the center rod. Three of these were inverted when I received the clock so the columns looked all messed up.

    I'm curious if anyone else has or has pictures of any other JUF Lunar clocks with this case.

    Eric
     
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  12. John Hubby

    John Hubby Principal Administrator
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    The DRGM 588490 was correctly identified by Eric, actually granted January 26, 1914 as “Monatsuhr mit Hohltrieben und Stiftengang”. This translates to "month-going clock with lantern pinions and pin pallets". These clocks are good runners and easy enough to work on but I've come across some with wear as described.
     
  13. etmb61

    etmb61 Registered User
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    #13 etmb61, Sep 5, 2018
    Last edited: Sep 5, 2018
    Here is the restored pendulum.

    pend_ba.jpg
    The two lower screws had to be dissolved out. The replacements are from a Schatz 53 three-ball pendulum. The threads are the same but they're about 2mm too long out the back so I'll need to cut them down.

    Also note the straight knurling on the adjustment disk, the rings that don't taper up to the hook, and the shape of the hook cutout. This is the earlier design.

    Now to that dial.

    Eric
     
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  14. etmb61

    etmb61 Registered User
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    Here is my first attempt at the new dial. I started with the picture posted by AndyDWA in another thread, cleaned it up in a paint program, and printed it on photo paper with a laser printer.
    new_dial.jpg
    It's not quite what I want but it looks ok (from a distance).

    The replacement back cover is from a seller in Australia who makes repro parts for several torsion clocks. It's a good match.
    back.jpg

    Since I did not rework the movement, this is how it will go in my display for now.
    front.jpg
    With the dome and pendulum of course.

    Eric
     
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  15. John Hubby

    John Hubby Principal Administrator
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    Great job, Eric!! When you get to the movement then it will truly be a showpiece.
     
  16. Mothyman

    Mothyman Registered User

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    Hi Eric

    You have a great looking clock. When you do get the movement repaired you might be interested in my experiences with the same clock.

    My clock has the same top bracket as yours and had a similar top block. After cleaning it suffered from uncontrollable flutter, and no amount of adjustment could stop it. You cannot raise the fork as it engages in the slot in the backplate.

    Searching the forum I found the same thread as mentioned by Kurt in post #6. In that you can see that the later clocks (those without the DRGM number) on the backplate have a very different top bracket with the top block mounted quite a bit lower.

    IMG_1127.jpg IMG_1130.jpg

    I fabricated an elongated top block which stopped the flutter completely, the clock is now running well – hope this tip will help you or anyone else with the same clock.

    Good luck with repairing the movement.

    Tim
     
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  17. etmb61

    etmb61 Registered User
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    #17 etmb61, Sep 20, 2018
    Last edited: Sep 20, 2018
    Tim,

    Thanks for the tip.

    I'm pretty sure it will run in its current state so I'll just hang a suspension on it and see what it does.

    I see your clock has the other DRGM stamped on the pendulum.

    Eric
     

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