Need help identifying replacement suspension spring

[HowardW]

I broke the suspension spring on my grandfather clock, inherited from my parents. It is a Ridgeway model, made in 1971. The label identifies it as "model number 166, movement G, finish Calais, serial number 4231". The spring is approx. 8 mm wide, but as it is broken, I don't know its exact length -- perhaps 15mm. At timesavers.com, they have several suspension springs which match the dimensions & general shape, so I'm unsure about which replacement part to obtain. Perhaps with the model information, someone at this forum can give some advice?

Attached are photos of the broken spring, with a cm ruler for reference.
Thanks, Howard
P.S. I believe the thickness of the top piece (with the hole for the pin) is about 3/64". I can't vouch for the accuracy of the device used to make this measurement -- I found it in a box of violin-making tools which my wife purchased at a garage sale.

 

[c.kugle]

The measurement to worry about the most is from hole to pin. The width should be as close as feasible but the pin to hole is more crucial.

 

[Curtis Brown]

Generally speaking most of the clocks that use these types of suspension springs are rather forgiving regarding getting a precisely matched suspension spring.

Timesavers has a huge assortment but looking at your photos I'd say this one is a close match:

#9 Suspension Spring

If they don't have that one in stock I suspect a #10 would work too.

 

[HowardW]

Thanks Curtis. My best candidates at timesavers were suspension springs #9, #10, Hermle #21-6, & Hermle #21-100.

And thank you too, c.kugle. To your point, because the old spring is broken, I don't know the correct hole-to-pin measurement.
For the above 4 candidates from timesavers, the hole-to-pin distances are respectively 10.5, 12.5, 12, & 12 mm. If the clocks don't require a precise replacement, then I may try one of the 12 mm ones.

 

[Curtis Brown]

Thanks Curtis. My best candidates at timesavers were suspension springs #9, #10, Hermle #21-6, & Hermle #21-100.

And thank you too, c.kugle. To your point, because the old spring is broken, I don't know the correct hole-to-pin measurement.
For the above 4 candidates from timesavers, the hole-to-pin distances are respectively 10.5, 12.5, 12, & 12 mm. If the clocks don't require a precise replacement, then I may try one of the 12 mm ones.

I'd say, based on your photos, that the suspension springs themselves (the two metal pieces that are broken) on your spring are relatively short. They tend to break right at the base. The photos suggest that's what happened with your spring. I bet your hole-to-pin distance is somewhere around 10-12mm and yes this doesn't need to be a precise match. I'm pretty sure the #9 will work. If you want to be sure buy the 9 and the 10 (and/or another) together. They're cheap and then you'll be sure.

Any small variability in precision in spring length can be made up in adjusting the pendulum bob.

 

[HowardW]

Excellent, I'll do that! Thanks very much, this has been extremely helpful.

The wonderful fellow who re-conditioned the clock when I inherited it around 6 years ago has unfortunately passed away since. There doesn't seem to be another repairman locally, so I'm forced to make the repair myself. I'm very grateful for the advice given here.

I'll get at least 2 of the likely springs at timesavers, considering that the shipping & "small order charge" come to more than the part cost. Then I'll be ready if I clumsily break the spring again.

(There was an envelope packed with the clock, with instructions for replacing the suspension spring, and containing a spring. So I thought this was going to be an easy 15-minute job. It turns out that the spring enclosed is nowhere near the correct size -- about 1" x 1/2" -- and is too thick to fit into the slot provided -- I have no idea how my dad came across a non-matching spring... Instead it's taken a few days and lots of internet time. But I should be OK now.)

 

[Curtis Brown]

I'll get at least 2 of the likely springs at timesavers, considering that the shipping & "small order charge" come to more than the part cost. Then I'll be ready if I clumsily break the spring again.

Let us know how you make out.

Oh and welcome to the message board!

 

[RickNB]

Given the very modest cost of #9 ($3.25), I would acquire one and try it out. If it works, it's fine. If not you're not out of pocket for much.

 

[shutterbug]

Request the parts book when you order. The pictures in it are actual size, so you can hold your spring against them to match.

 

[Dick C]

Given the very modest cost of #9 ($3.25), I would acquire one and try it out. If it works, it's fine. If not you're not out of pocket for much.

Add significant shipping costs to this. I might buy 3 or 4 at one time.

 

[HowardW]

Let us know how you make out.

I ordered three different types of springs from timesavers.com. [To avoid the "small-order" fee, I also got some parts for a Jefferson "Golden Hour" clock -- unfortunately, blind ordering as the clock is at my winter home, so not sure if I've ordered all the necessary parts.] When they arrived, I could directly compare to the remnants of the old spring, and none of the three matched exactly! Armed with the knowledge that one doesn't need a perfect replacement, I proceeded...

I was unable to find the pin which holds the suspension spring, despite having been careful -- or so I thought -- to place all small parts removed in a little plastic sandwich bag. Rookie mistake. It turns out that a short piece snipped from a paper clip serves the purpose. (Later I located the missing pin on a table next to the clock.)

I was able to insert the new spring and connect the pendulum support (don't know the correct name) and the pendulum. Got it running! Had a little trouble with the chimes -- it worked for about a day, then stopped -- but I think that's resolved now.

Thanks for all your help! I like this forum.