kinder, gentler mainspring for time clock?

[bruce linde]

got this burk time clock movement w/ remontoire. the remontoire ticks away for 59 seconds and then moves the minute hand ONCE a minute around the dial... 60x per hour. more info and video are available in a previous thread: mechanical remontoire clocks, aka 'minute jumper'

the thing is a beast to wind... and then only runs for about four days. as you can see from the pics the barrel is 3" in diameter and 1" tall. the mainspring measures about .56mm thick (varies a bit depending on how hard i work the calipers).

my question is: given the barrel size and remontoire... can i replace this with a new mainspring that will 1) run a full 8 days (or more, given the barrel size) and 2) be easier to wind. i am a bass player with pretty strong hands and winding this thing takes a ridiculous amount of effort.

also... didn't notice it before, but someone did a nice job repairing some teeth on the barrel's second slip-on gear...

 

[Uhralt]

Unless somebody has tried this before I think it will be a case of trial and error. Time for an experiment. You probably have a typical 8-day spring (3/4x0.018x96) somewhere in your shop. Cut off the loop and make a hole in the end. Then put it into your barrel and see if the clock runs. If it does, you can replace the spring with one of the appropriate width and similar thickness and length. You can also use the mainspring calculator to find the best length for the spring. This is what I would try.

Uhralt

 

[bruce linde]

thx... do you think the size of the barrel will be an issue? i.e.. with a regular mainspring able to expand out farther than usual?

 

[Uhralt]

thx... do you think the size of the barrel will be an issue? i.e.. with a regular mainspring able to expand out farther than usual?

I think there is a chance that it may work. Three inches is rather wide for a barrel, maybe comparable to a Seth Thomas #10 movement barrel which runs for eight days.

Uhralt

 

[bruce linde]

timesavers has a mainspring for the seth thomas #10, but it's .69mm thick... even thicker than the spring i currently have.

i think i'll try their 1000 day clock mainspring: .827" x .015" x 100" 1000-Day Hole End Mainspring (21 X 50) ... the width and extra length should fit easily in the barrel, and at .381mm it's about 2/3 the thickness of what's in there now. i can turn the gears fairly easily by hand and think it will work.... we'll see.

i only have $10 into the clock, so what they heck!

 

[Uhralt]

timesavers has a mainspring for the seth thomas #10, but it's .69mm thick... even thicker than the spring i currently have.

i think i'll try their 1000 day clock mainspring: .827" x .015" x 100" 1000-Day Hole End Mainspring (21 X 50) ... the width and extra length should fit easily in the barrel, and at .381mm it's about 2/3 the thickness of what's in there now. i can turn the gears fairly easily by hand and think it will work.... we'll see.

i only have $10 into the clock, so what they heck!

.015 might be a little thin. The power of the spring goes with the square of the thickness, so 2/3 thickness is only 44% of the power. Why don't you just try what I suggested? You don't have to wait for Timesavers shipment to get your answer. But maybe I tend to be to be too impatient.

Uhralt

 

[bruce linde]

.015 might be a little thin. The power of the spring goes with the square of the thickness, so 2/3 thickness is only 44% of the power. Why don't you just try what I suggested? You don't have to wait for Timesavers shipment to get your answer. But maybe I tend to be to be too impatient. Uhralt

basically because i'm lazy, a shopaholic, and the only mainsprings i have on my bench are ones i took out of a fusee (too wide) and out of a seth thomas gallery clock... because they were time clock mainsprings and too heavy!

i do appreciate your input... i think (hope) the power will be sufficient and will be going through the movement one more time in the meantime just to make sure everything moves freely.

 

[Uhralt]

basically because i'm lazy, a shopaholic, and the only mainsprings i have on my bench are ones i took out of a fusee (too wide) and out of a seth thomas gallery clock... because they were time clock mainsprings and too heavy!

i do appreciate your input... i think (hope) the power will be sufficient and will be going through the movement one more time in the meantime just to make sure everything moves freely.

I just assumed that everybody has a bunch of old mainsprings of that size sitting around. I certainly do from the times that I replaced mainsprings more often than I do now. And of course, I don't throw them away because I might use them for making something else.....

Uhralt

 

[bruce linde]

i'm more of a weight-driven seconds pendulum kind of guy... mainsprings scare me, because i've been bitten before.

i've also haven't been doing this as long as you... just a few years.

i really appreciate the insights and experience you all share on the MB!

 

[glenhead]

If you indeed have a "typical 8-day spring" that Uhralt suggests, I'd sure as heck give it a shot. If not I'd give the 1000-day spring a try. The worst that happens is that the clock won't run for beans, right? (Well, that and you'll be out 30-ish dollars with shipping.) Since the 1000-day is a bit wider than the 8-day it will probably provide nearly the same torque. (I'm not gonna do the math on a Sunday morning!) The newer alloys are inherently springier than the ones from several decades ago so it may have enough oomph to push things well enough. Either one is thin enough to give a nice long run time. Let us know what you decide and what it does. Interesting experiment!

Glen

 

[shutterbug]

I'll have to ask the more obvious question: When the clock stops, is there a lot of power still in the spring? If you let it down at that point, how many turns are left in it? You might be making the newbie mistake of assuming it's one thing, when it's really another

 

[bruce linde]

newbie mistakes? moi?!?!?

when the spring runs (ran) down after four or so days there was no power... and it was loose when starting to wind but almost immediately really hard to wind.

i pulled it and it's more than 100" long. you can see it with tension released above... maybe it was 'tired'/set? i suppose i could have tried stretching it out to see if i could regain power and duration, but would still have the too-hard-to-wind problem.

hoping the new one will provide enough power and run a full eight days... trial and error, yes?

 

[shutterbug]

Yeah. I just wanted to be sure you were kicking the correct prone horse That one might just be asleep.

 

[tom427cid]

Hi all,
I have encountered this problem with the Seth Thomas and a look alike movement in time clocks. The reason for the massive spring was not so much to power the movement but to operate the stamping mechanism. I have used 3/4 x .019" x 108 main springs with success. I have also thought about using the mainspring for a Sonora chime. I think it is .022" thick. However the .019" spring seems to be adequate for an eight day run. I disconnect the driveshaft to the stamping unit and overhaul the movement. Sometimes it is necessary to locate a donor movement because of damage to the lower wheels. Because this is a deadbeat escapement, pay attention to the escapement set up. The other issue you will encounter is mounting the inside coil of the mainspring on the winding arbor. The coil needs to be enlarged and I use a long taper punch, seems to work the best.
Check the dimensions of the barrel, I think that the spring should fit just fine.
Hope this helps
tom

 

[bruce linde]

well, the 1000 day mainspring was, as urhalt predicted, not beefy enough. the remontoire actually doesn't function until it's under pressure from the wound great wheel, and then requires power to snap back to the top and start counting down again... moving the minute hand to the next minute.

i've ordered the sonora mainspring mentioned by tom... slightly less beefy than what i had in there (.55mm compared to .60) but also longer, wider and certainly fresher than what was in there before. if i can't solve the hard-to-wind problem, i'd at least like it to run for a full 8 days so i don't have to wind it mid-week.... my other clocks get jealous.

and... before you say i'm a nut for blowing $50 on mainsprings, a couple of things: the clock cost me $10 on craigslist and i look at it more like i just took 'getting a feel for mainsprings 101' at the university of nawcc...

clock: $10
1000 day mainspring: $20
sonora mainspring: $30
messing around with the clock instead of doing real work: priceless

 

[shutterbug]

Depending on where you bought them, you could likely return them for a refund of the purchase price (but not the shipping).

 

[bruce linde]

timesavers.... not a big deal either way.... i did put the mainspring in, so it's not new anymore... i wouldn't want one that someone had already put in somewhere.

 

[bruce linde]

ok... final report. i put in the sonora chime mainspring from timesavers ( 1.0" X .022" X 136" Sonora Chime Hole End Mainspring )... the movement likes it, it winds way easier, but it stops after six days (plus a bonus couple of hours). that's an improvement over the four i was getting, but i guess it's still on my 'wind twice a week' list.

i tried moving the counterweight in as much as possible to reduce the effort the movement needed to expend to raise the remontroire back up after it ticks away 60 seconds (and moves the minute hand).... could tell a difference but didn't really change how long it would run. it helped the arm raise back up easier, but also makes it a touch harder for the rementoire to tick down each time as it loads up before release.

 

[Bruce Alexander]

Appears to me that your mainspring is a little short. If you haven't already done so, I'd recommend checking the length using this calculator: http://www.nawcc-index.net/CalcMainspringLength.php

 

[bruce linde]

Appears to me that your mainspring is a little short. If you haven't already done so, I'd recommend checking the length using this calculator: http://www.nawcc-index.net/CalcMainspringLength.php

well, maybe... but the sonora mainspring was the largest/longest hole-end mainspring i could find:

1" wide x .22" thick x 130" long...

is there a comparable width and thickness mainspring longer than 130"? i thought for sure that would do it...

 

[Willie X]

If it runs good and the spring is slack at
4 to 6 days, two things come to mind: The spring is not long enough, or the clock is designed to do only a few days on a wind. Three days would get you over a weekend or holiday. Willie X

 

[bruce linde]

If it runs good and the spring is slack at 4 to 6 days, two things come to mind: The spring is not long enough, or the clock is designed to do only a few days on a wind. Three days would get you over a weekend or holiday. Willie X

The original spring gave me four days, the new spring gives me six

The barrel is big and could accommodate a longer spring, if anyone made one. Again, 130 inches was the biggest I could find. Do you guys ever extend mainsprings?

 

[Uhralt]

The original spring gave me four days, the new spring gives me six

The barrel is big and could accommodate a longer spring, if anyone made one. Again, 130 inches was the biggest I could find. Do you guys ever extend mainsprings?

I didn't find a longer one either at Timesavers. Maybe they do exist, for example for grammophones or big music boxes but I don't know where to look for them.

Uhralt

 

[Bruce Alexander]

well, maybe... but the sonora mainspring was the largest/longest hole-end mainspring i could find:

1" wide x .22" thick x 130" long...

is there a comparable width and thickness mainspring longer than 130"? i thought for sure that would do it...

Okay. If the calculator indicates a long spring is needed to fill half of the space available in your 3 inch barrel, you might need to go to a custom made spring.

Here's a list of sources: Mike's Clock Clinic's Listings of Companies Who Offer Trade Repair & Horology Resources
Hopefully one, or more of them might help. (I know there is a listing on the NAWCC Message Board itself but I can't seem to find it).

Your other springs can definitely go into your inventory. Sonora clocks are plentiful and collectible. Little doubt you can find a use for that one. Seth Thomas also made a few Sonora Wall models. Very collectible and more in line with your preferences.

Good luck with it Bruce

 

[shutterbug]

Extend a main spring? Interesting question. It would for sure need to be hard soldered or brazed ... but I would think it would be possible to do. Might end up in the HOS thread later though, if someone thinks it was a bad spring repair

 

[bruce linde]

it's not that important to me... six days is fine... but i appreciate all the comments. thx.

 

[Uhralt]

I have a few weight driven clocks that I wind twice a week even though they would run for a full week. These are "wag on wall" clocks where the weights are not enclosed in a case. I think these clocks just look odd when the weights have dropped almost to the floor. My winding days for these are Sundays and Wednesdays.

Uhralt

 

[Bruce Alexander]

If the clock is for your own collection, that's always an option.

 

[RJSoftware]

are you possibly using wrong key? Some of the heavy duty recorder punch clocks use a massive key with big wings. I cant even imagine winding them with regular small key. The square of shaft might be same but a normal keys wings too small. just curious.