Pendulum Spring Advice

Petec

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Jun 5, 2014
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See the pic. I believe the broken part is called a pendulum spring. Back in 1974 when I repaired this clock the first time the same part was broken. I worked around some machinists and one of them took a look at it, went over to his parts drawers and pulled out this strip of metal and gave it to me. He has passed away and the same for the company.

Over all it is 85 mm long. The broken piece is 5.5mm wide. I can't get a reading on the thickness with my dial caliper.

I have searched Timesavers and found both a Suspension Spring $7.00

-suspension-spring

But it is 0.10mm. Far thicker then my part.

I also found a Suspension Rod- Pendulum $1.50

suspensionrod-pendulum

Should I get the rod or could that give me a problem?


pendulumrod.jpg
 

Willie X

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Feb 9, 2008
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Normally the spring and rod would be bought and installed as one piece. This is usually called an 'American style suspension rod'. The most common size for the spring is .003". This will work in nearly all old American movements. They all come from India now and cost about 3 bucks/dozen.

Do not buy the 'one piece' suspension rods, they are not made correctly and often cause problems.

Note, your machinist friend likely used steel shim stock. It is soft and bad about bending (and eventually breaking) but if unmolested, can work great for a very long time.

Willie X
 

Petec

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Jun 5, 2014
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I'm sorry the links didn't work. Try again:
Suspension Spring
Suspension Rod Pendulum

I think you are saying the second option is what I should go for.

And, the machinist's shim stock lasted 48 years and most likely would have kept working except......the spring that makes the chime main wheel ratchet poped off as I was winding it and spun the key out of my hand and jammed a bunch of stuff inside. It also took a chunk out of the face of the clock. Soon I will be looking for a way to repair that.
 

ChimeTime

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May 4, 2021
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Going a bit further than Willie's wise words....
• The very first thing I'd want to do is take some measurements while you still have all the pendulum Leader and suspension spring pieces. The length of the pendulum is critical to good time keeping. If you can't restore a similar pendulum length, then all is for naught.

• The spring will need to overlap the top of the Leader and be reattached. I might use a #2-56 machine screw, washer and nut, or maybe you have copper rivets.

• An option for your spring would be the raw 0.003" spring steel sheets that Timesavers sells (#10576). This can be trimmed with household scissors to any width and length. Holes can be added with standard drill bits. This way, the new spring won't be at the mercy of a catalog photo.

Hope these ideas help.
 

Willie X

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Merritt's P-111 will do it. Make it a little longer than the old one. It's easy enough to shorten it a bit if necessary.

It's described as a 'three piece' but it's just a single item, 12 of em. Willie X
 
Last edited:

demoman3955

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Apr 9, 2022
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Do not buy the 'one piece' suspension rods, they are not made correctly and often cause problems.



Willie X
well that bit of info would have been nice for me to know before i bought a bunch of them... lol
 

Petec

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Jun 5, 2014
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Well, I didn't see the last three posts above. I was sure I refreshed the screen. Anyway, I bought 5 of the "rod pendulum".
From the dimensions, it should work. I wonder what could go wrong with them?

Mine attaches using a wire slipped through the hole near the top.
 

shutterbug

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They will probably be fine. When they're bad, it's usually noticeable from the get-go.
 

demoman3955

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Apr 9, 2022
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They will probably be fine. When they're bad, it's usually noticeable from the get-go.
ive already used 5 and all on mantel clocks and no problems thus far. as cheap as they are, i sure wont sweat it.
 

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