Changing mainspring for more power?

Discussion in '400-Day & Atmos' started by KurtinSA, Apr 29, 2020.

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  1. KurtinSA

    KurtinSA Registered User
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    I find that the midgets, and most miniatures to really be tough to work on. They're on the ragged edge for power vs friction. So, I reached the testing stage on the Konrad Mauch #1396 and it will run somewhat weekly with no motion works, but as soon as I add the motion works and hands, it can't lift the minute hand past 0:45. Funny thing, though, I had it running with the hands, for a number of hours and then I noticed that it was running fast, so went to the adjuster to slow it down. After that, it won't run. The top saddle is not loose enough to have changed. All I did was grab the pendulum, rotate the knob, and start it running again. Sigh!

    So, in looking at the guide, they mention two springs with the larger spring to provide more power. It calls for 12x25 or 14x25. But further it says that Mauch increased the distance between the plates, 20mm to 21mm, in order to accommodate a different barrel. In my case, the plates are 20mm apart.

    Looking at the guide, I see a 12x24 main spring with an increased thickness but a reduced length. The thickness would give me more power, but it might not run 400 days. If I've run out of options elsewhere, is this something that is done? Guess I'd make a future owner/repairer mad when they found out!

    Kurt
     
  2. tracerjack

    tracerjack Registered User
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    Yes, midgets are...can't think of a single word to describe them, but I sure do like the way they look and have four of them. Well, if you decide to change springs, let us know how it comes out.
     
  3. Wayne A

    Wayne A Registered User
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    Don't have a Koma midget yet but I like the miniatures and midgets, there all I will buy. Last Koma miniature I picked up was not in the guide with a large W4 on the backplate. Its mainspring was very stiff and tightly wound, did not check the thickness though but it seemed extra thick, do have a picture attached. Was thinking as I wound it this clock its not going to run 400 days because of so few turns to fully wound. Its running well but had to run a lower fork to get enough overswing. Overall its rotating 280deg after some run time.

    Think they operate with so little extra power that every little detail needs to be as optimal as possible, perhaps oddly its one of the things I like about them. :)

    20200407_123505.jpg
     
  4. Wayne A

    Wayne A Registered User
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    Adding a but more to this.
    Apart from the typical friction spots of pivots and gear burs I work to be sure the pin is centered vertically in the center of rotation of the pendulum. Sometimes the pin is a little bent or the pallets are maladjusted so the pin rotates further to one side of vertical than than the other. Found clocks that the pin never even moved beyond vertical in one direction, this creates sharp angels between the pin and fork and can result in binding and loss of power and the need to run large fork gaps promoting flutter.

    Wayne
     
  5. KurtinSA

    KurtinSA Registered User
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    I try to check all those things. I've done all I can do with this clock so I'll see if I can "cheat" in some way. BTW...this is a pin pallet clock and I don't have a lot of confidence working with that...easier to deal with the regular escape wheel and pallets.

    Kurt
     
  6. clksmyhobby

    clksmyhobby Registered User

    Jan 29, 2011
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    Hi Kurt,
    I have an Adorna carriage-style clock, midget design by Koma, plate # 1471C. I had last worked with it 6 years ago having found it in very sorry shape, but complete, in a thrift store. After cleaning and installing a new suspension unit, I thought it would run but alas, it would not. Your post piqued my interest in it again.

    So, I began again after verifying it still will not run more than about 30 minutes. Broke it down, cleaned and polished everything. It has the smaller main spring and everything seems good until final assembly. With only the minute hand installed, it ran for two days, rotation about 225 degrees with over swing. With all components in place, it stops. The hand tension seems good and there is no contact with the hour hand. Remove everything except minute hand and it will not run to lift the hand beyond 9 o'clock. Remove the minute hand and it will run. Deja vu!

    So I am interested to hear if and when you try another main spring. In the interim, I will continue to tinker with it.

    I also have a midget Haller, plate # 1522, with similar issues.
     
  7. KurtinSA

    KurtinSA Registered User
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    I'll let you know...I might wait a bit until I build up an order for the Horolovar store.

    My clock is plate 1396. Mine has no tension washer which I thought was strange. This clock, though, has an arbor that goes through both plates which is used to turn the motion works to set time...can't get to the dial from the front. My thinking was that maybe the extra arbor might provide the resistance needed to hold the minute hand in position...I never saw it drop to straight down unless the hand nut was too loose.

    Kurt
     
  8. clksmyhobby

    clksmyhobby Registered User

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    My clock also has that arbor and gear for setting the time. Plenty of fore and aft play allows the gear to be disengaged until needed. No tension washer in mine, but there is a flat washer under the cannon pinion.
     
  9. KurtinSA

    KurtinSA Registered User
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    I found nothing under the cannon pinion...and I assembled it the same way.

    Kurt
     
  10. clksmyhobby

    clksmyhobby Registered User

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    Interesting. Without the washer, the minute hand on mine is either too tight or too loose. Seems like we are looking at the same point as Dells post about a Koma standard a couple of weeks ago.

    My back plate is stamped 6 57.
     
  11. KurtinSA

    KurtinSA Registered User
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    My plate has no date stamp...didn't think Konrad Mauch did that.

    As for the washer, I'm not totally clear on it's use. If there's a tension washer, then it might be needed to prevent the points from digging into the cannon pinion. If the cannon pinion hole is too big, the washer when put on first would prevent the cannon pinion from slipping too far onto the arbor. There is a shoulder on the arbor that is proud of the front plate, so the cannon pinion can't go far enough as to rub on the front plate.

    Kut
     
  12. clksmyhobby

    clksmyhobby Registered User

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    Without the washer the cannon pinion fits over the shoulder and can rub the front plate, so it is necessary though maybe not original. Perhaps the date stamp was for the importer Perfecta Watch & Clock Company. Will continue to tinker until something else strikes my fancy. Would like to have it running before full assembly and back on the shelf, but it's waited this long so no worries.
     
  13. KurtinSA

    KurtinSA Registered User
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    On my clock, the cannon pinion does not touch the front plate, even without a washer.

    Kurt
     
  14. clksmyhobby

    clksmyhobby Registered User

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    Kurt,

    I have a number of clocks still packed up from my last move. One of them is a Haller miniature, plate 1521AA. I retrieved it and set it up. It ran despite being boxed and stored for over 4 years.

    I removed the main spring, cleaned it, lubed it and installed it in the barrel for the Koma midget, as you have speculated. The winding tension was noticeably more and I had good escape wheel movement with 1 full turn. Wound it about 1/2 way to full and observed very distinct escape action. After 8 hours or so, the total rotation was just over 180 degrees with nearly 30 degrees of over swing. This is with the minute hand installed and hand nut tight. Raised the fork to approximately 1 mm higher than Horolovar picture for unit 38A and fully wound the clock. This morning rotation was about 225 degrees with significant over swing. Will complete assembly today, leaving the Haller main spring installed. Only time will tell how it goes. I will order a new spring for the Haller.

    Math says the Koma will not run 400 days (23"/27" X 400 = 340 days). Since it is mine and I wind my operating clocks 3 times a year, I am happy.
     
  15. KurtinSA

    KurtinSA Registered User
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    Thanks...that's certainly promising!

    Kurt
     
  16. clksmyhobby

    clksmyhobby Registered User

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    As it turns out, my Haller midget also runs fine with over 270 degrees rotation. My other similar problem (other than the Koma) is a miniature Welby by Hermle, plate 1581. Same frustrations as with the Koma - apparently not enough power for consistent operation. Time to dig it out and give it a go.

    Will update you if I make any other changes or observations of importance.

    Will send photos when completed, hopefully today.

    Best regards,
    Mike
     
  17. KurtinSA

    KurtinSA Registered User
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    Got the 12x24 spring in. Made the swap. Clocked seemed better after starting around 4:00pm. Found the clock had stopped around 6:43pm, so not that great. Before, I don't think I could get it to raise the minute hand even once. This time, it raised it page 4:45 and also 5:45 before stopping an hour later. Pretty frustrating...not sure where to go. I haven't inspected the clock for the need of bushings...I've run across clocks lately that need bushings, and I've set those aside for now.

    BTW on the main spring swap...the inner coil on the 12x24 is meant for a smaller winding arbor than this clock. I had to work hard to open up the inner coil to accept my arbor. Even still, I really had to force my arbor in and get it to catch the spring hole on the arbor.

    Kurt
     
  18. clksmyhobby

    clksmyhobby Registered User

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    Hi Kurt,
    Roger on the arbor size adjustment. My Adorna (Koma) is running since May 7 with just over 240 degrees rotation and 30 degrees of over swing. It is quite lively to watch especially considering its past performance. The only adjustment I made after the main spring change was to raise the fork a bit.

    Mike
     
  19. KurtinSA

    KurtinSA Registered User
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    I have limited experience, but I see several of the arbors "jumping" in their bushings when I move wheels back and forth. So, guess I'll put this away until I get the nerve to bush the plates.

    Kurt
     
  20. clksmyhobby

    clksmyhobby Registered User

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    Rebushing not in my skill set. I have some vintage 8-day mantle clocks that look nice on the shelf, but won't run from elongated holes. One day - maybe.

    I do check my 400-day clocks and have not found any so far. I have four clocks with 1930s vintage but most are from the late 40s and up - no disc pendulums yet.
     
  21. KurtinSA

    KurtinSA Registered User
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    I probably have 6-8 that won't run and have determined that there's too much slop which can contribute to problems. I don't know if the slop in the holes is what's causing the clock not to run, but it can't be a good thing.

    Kurt
     
  22. clksmyhobby

    clksmyhobby Registered User

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    That is true. Received the new 12x24 spring to put into the Haller midget on the bench. Decided to leave the old one in the Koma and check its endurance. Hope to get to the Haller this week.

    Mike
     

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