GILBERT CLOCK MOVEMENT SPRINGS

Discussion in 'Clock Repair' started by BOBJAYR, Jun 5, 2020.

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  1. BOBJAYR

    BOBJAYR Registered User
    NAWCC Member

    Mar 12, 2009
    440
    2
    18
    Male
    ARIZONA
    Country Flag:
    Starting to restore Gilbert clock movement(late 1800's). Very dirty
    and want to put new springs in DSC01314.JPG during restoration. The strike spring
    looks like it might be an original spring and the time spring probably
    was replaced at some time.

    Original strike spring measures 96", the time spring which I think is
    a replacement measures 110".

    Not sure why they differ this much. Can anyone give me what length
    spring should be in this clock. Should they both be the same length
    or for some reason there should be a difference in the length between
    the strike and time.

    See attached photo of movement.

    Thanks, Bob
     
  2. R. Croswell

    R. Croswell Registered User

    Apr 4, 2006
    10,326
    867
    113
    Male
    Trappe, Md.
    Country Flag:
    Region Flag:
    If the springs are OK I would not replace them. The 110" time spring is probably 108". Increasing the length beyond the typical 96" can help even out the power over a 7 day run. You might want to go with 108" on the strike side as well so the strike doesn't run down before the time. I would expect the springs should be about 0.0165" thick. These open spring movements are not critical as long as you have at least 96".

    RC
     
  3. lpbp

    lpbp Registered User
    NAWCC Star Fellow NAWCC Life Member NAWCC Member

    Aug 25, 2000
    2,905
    44
    48
    Country Flag:
    Region Flag:
    Some people use a thinner longer spring, as most were overpowered in the begininng.
     
  4. BOBJAYR

    BOBJAYR Registered User
    NAWCC Member

    Mar 12, 2009
    440
    2
    18
    Male
    ARIZONA
    Country Flag:
    Thanks for your reply. Both springs are pretty rusted so I am afraid one of these days they will break. I meant to give the width and thickness in my message. The 108" time spring is .70" in width and .018 thick. The 96" strike spring is .75" in width
    and .022" thick.

    It sounds like the 96" spring is typical but the 108" would give more even power thru out the weekly run. Which width would be typical the .70" or the .75"? Bob
     
  5. Uhralt

    Uhralt Registered User
    NAWCC Member

    Sep 4, 2008
    4,849
    575
    113
    Country Flag:
    Region Flag:
    The longer a spring is the "softer" it becomes. It will have less power but a more even power over the runtime of a clock.

    Uhralt
     
  6. R. Croswell

    R. Croswell Registered User

    Apr 4, 2006
    10,326
    867
    113
    Male
    Trappe, Md.
    Country Flag:
    Region Flag:
    For a clock like that 0.022" thick is too thick. But it can be difficult to accurately measure a curved spring. I would consider 0.018" thick max for both sides.

    RC
     
  7. BOBJAYR

    BOBJAYR Registered User
    NAWCC Member

    Mar 12, 2009
    440
    2
    18
    Male
    ARIZONA
    Country Flag:
    Thanks RC. Would the typical width be .70" or .75", Bob
     
  8. kinsler33

    kinsler33 Registered User

    Aug 17, 2014
    3,318
    377
    83
    Male
    Science teacher, writer
    Lancaster, Ohio, USA
    Country Flag:
    Region Flag:
    The springs may well break, but probably not due to rust. I'd just pull them out, clean them off, lubricate and put them back in the clock. It is the nature of clock repair that there's no way to tell (1) when or why or in what manner a mainspring might break or (2) the proper size of the mainsprings for most old clocks without measuring the old one and guessing a lot.

    I just had the time spring on an old open-spring Seth Thomas (89, maybe) break into about thirty pieces after I wound it on the spring winder, clipped it, and slipped it onto the main wheel. There wasn't any sort of explosion--the pieces just sort of fell into a pile. I stood there looking at it for quite a while.
     
  9. R. Croswell

    R. Croswell Registered User

    Apr 4, 2006
    10,326
    867
    113
    Male
    Trappe, Md.
    Country Flag:
    Region Flag:
    #9 R. Croswell, Jun 6, 2020
    Last edited: Jun 6, 2020
    Bob, American 8-day open spring clocks typically use springs that are 0.750" wide for both the time and strike, but there are a few exceptions. Sometimes the time and strike are not the same. But because springs can and do bust, one cannot be sure whether the springs we find in a clock are the original size. My spring charts indicate the sizes for Gilbert 8-day time & strike are; 0.750" x 0.0165" x 96", or 0.750" x 0.017" x 120" or 0.750" x 0.0165" x 96". I have a similar Gilbert and I used 0.750" x 0.0165" x 108". These are all standard sizes. You can get a pretty good idea of the original spring width by measuring the space between the main wheel and the end of the arbor (base of the pivot). The spring should be a bit less than that amount to provide clearance and under no circumstances should the spring extend beyond the end of the arbor.. If there is space for a 0.750" wide spring, I would suggest using the.0.750" x 0.017" x 120" or 0.750" x 0.0165" x 108". I rarely use 0.018" thick, and would never use anything thicker than 0.018" thick is this clock.

    Other than having the correct size, the two main things to look for are that there are no cracks, and that the spring is smooth. I replace springs that have actual rust pitting, but surface rust can usually be removed with steel wool etc. I would avoid replacement springs made in India and China. Nothing against the fine people who live there, but too many reports of these products failing or even arriving shattered. Unfortunately, we can't always tell where a replacement spring is made and frequently the quality is not as good as the spring we are replacing.
    '
    RC
     
  10. shutterbug

    shutterbug Moderator
    NAWCC Member

    Oct 19, 2005
    43,454
    1,235
    113
    Male
    Self employed interpreter/clock repairer
    North Carolina
    Country Flag:
    Region Flag:
    Quite a number of clock makers used the standard .75" X .018" X 96" springs, and that's what many repairers use as their 'go to' spring when the original is unknown. So it's possible that the strike spring is the one that was replaced. But the replacement springs available now are always a crap shoot, and you're usually better off using what you have than replacing.
     
  11. BOBJAYR

    BOBJAYR Registered User
    NAWCC Member

    Mar 12, 2009
    440
    2
    18
    Male
    ARIZONA
    Country Flag:
    RC: Thanks very much for your detailed explanation concerning mainsprings. Will have to remember your suggestion to check the width between the main wheel and the end of the arbor(base of the pivot) to get an idea of the original width of
    a spring. The .750 width on this clock does allow for a bit of clearance. I am going with your suggested sizes. Thanks again RC, Bob
     
  12. Bruce Alexander

    Bruce Alexander Registered User
    Sponsor NAWCC Brass Member

    Feb 22, 2010
    6,893
    622
    113
    Country Flag:
    Region Flag:
    You can, and perhaps should contact your supplier and ask them about their mainspring source.

    I contacted Merritts back in October of 2018 and received this response:

    "P" stands for pass. ;)
     

Share This Page