Note May 14, 2010: The newest batch of these spring that I received are too weak for most clocks. When released from their clamps, the springs open out only to about 5 inches (as compared to over 11 inches on the original batch). I cannot recommend these springs any more. I just tried one on the time side of a Seth Thomas No. 89 movement, and it was too weak to be satisfactory.
Merritt’s Antiques has a new 3/4 inch by 0.0165 inch by 96 inch mainspring for American clocks. It is part no. P-1956, currently selling for $7.00 each individually (quantity discounts are available). It is a higher quality, American made version of their P-1496 that I have blogged about earlier.
I bought one of these springs to test. The quality appears to be excellent. The thickness measured as specified, 0.0165 inches. It is tempered to a nice uniform blue, and is well finished with a nicely made, neatly attached loop end.
It seems to have plenty of power, as the coils open way up when the spring is first uncoiled. It may be too strong for some clocks.
Tomorrow I am going to install it in an Ansonia long drop octagon clock with early type movement.
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[…] Strike mainspring: 3/4 x 0.0163 inch. (Unfortunately, I had to replace the strike mainspring because it had a rough action when nearly wound, typical of springs that may break soon. I used a new Merritt’s Antiques P-1956). […]
[…] years ago, I wrote about the P-1956 mainspring from Merritt’s Antiques. This spring was ideal for many antique American […]
[…] (0.02 inch). Both springs were stiff and very hard to remove from the mainwheels. I installed new Merritt’s P-1956 mainsprings that are 3/4 by .0165 by 96 inches. They provide a good escapement action and striking […]
[…] spring was 0.0178 inch thick. I replaced both with thinner mainsprings, Merritt’s Antiques P-1956, 0.0165 inch thick, to reduce future wear to the mainwheel teeth. The escapement takes an excellent […]
[…] Time mainspring: The original time mainspring was broken, and measured 3/4 inch wide by 0.018 inch thick. The replacement is 3/4 by 0.0165 by 96 inches, Merritt’s P-1956. […]
[…] strong. The thinner one was replaced because it did not unwind smoothly. Both were replaced with Merritt’s P-1956 springs 3/4 inch wide x 0.0165 inch thick x 96 inches […]
I recommend the type listed in the post above (part number P-1956), available from Merritt’s Antiques. There is a link to Merritt’s in the post.
I have an old 8 day ingraham mantle clock that needs both mainsprings replaced. Where can I find and buy two mainsprings and is there a certain kind I need to buy. Thank you
[…] This clock was a good example of original thin Seth Thomas mainsprings. The time mainspring is 3/4 inches wide and 0.0159 inches thick. It is in good condition and was retained in the clock. The strike mainspring was 0.0164 inches thick. I intended to keep it in the clock, but it broke after cleaning, so I installed a 3/4 inch wide, 0.0165 inches thick, and 96 inches long, Merritt’s Antiques part no. P-1956. […]
[…] The strike mainspring was a replacement that was too thick (0.018 inches). I replaced it with a spring 3/4 inch wide, 0.0165 inches thick, and 96 inches long, Merritt’s Antiques part no. P-1956; […]
[…] the time mainspring with one of the new Merritt’s 3/4 x 0.0165 x 96 inch […]