Measuring mainsprings

Vernon

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Dec 9, 2006
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I wanted to try a safe and accurate way to measure this spring from an anniversary clock. I spray painted a sheet of paper then set the spring straight down in the wet paint and then removed it. With the spring removed and the paint dried, I traced the line with a pencil which helped highlight the line against the black. I then used my map measurer to get the exact length. Maybe I'll try a different color the next time.
First picture is before tracing.

IMG_20210802_104115.jpg IMG_20210802_110446.jpg
 

Willie X

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Feb 9, 2008
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Get the book ... "The Horolovar 400-Day Clock REPAIR GUIDE" by Charles Terwilliger. Nearly all MS info is in 'the book'.

Also, you don't need a new edition. My 1982 edition is just fine and the mainspring is probably not your problem.

:) Willie X
 

Bruce Alexander

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Feb 22, 2010
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Hello Vernon,

To get a close approximation of the installed springs, I use thin string and lay it around the coils. Once I get over the inner coils, if there isn't enough room for the spring between the coils, I can still lay it on top of the gap between the coils to get as accurate a measurement as possible.

Works for me.

Good luck,

Bruce
 

Vernon

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Dec 9, 2006
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Willie X,
I do have the book but didn't think to check there. This clock has a lot of issues but I simply wanted to present a way to measure the current spring safely.
Thank you!
 

Vernon

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Hey Bruce,
I recall reading about your idea before. I need to try it!
I must say that it is difficult to hold position using the map wheel. Maybe the use of a lazy susan (rotating table) would help.
Thanks
 

R. Croswell

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Apr 4, 2006
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I have a box of old tractor feed printer paper and I gather several sheets shear off a slice about 1/2" - 3/4" wide (can also cut a slice from adding machine paper tape). Start in the center and feel the paper strip around the spring coils, then measure the paper strip. A dressmaker's measuring tape is recommended by some.

RC
 
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shutterbug

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I just measure as best I can with a tape measure, and estimate the inner coils. If you're within 6 inches or so, you're good to go
 
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