Carriage Clock Speed Mystery

David D'Apice

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Mar 22, 2012
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Good evening. I've just completed a carriage clock (an oversized one) -- it has been running gladly for the last few days ---- it tends to run about two minutes slow per day -- and I have increased the mainspring strength from .011 to .0118 in the hopes of speeding it up ever so slightly -- the regulator is far toward the advance position as much as possible.

Does anyone have a tip to gain this slight amount --- what if I were to shorten or lengthen the hairspring by a 32nd or so == would that help. Or is that just crazy. Any help appreciated. The clock is a lever escapement of nice quality that has been beaten pretty badly -- when I bought it, it had 4 mashed teeth on the time barrel, and some broken glass. Any ideas?
 

dAz57

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Dec 7, 2011
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Well you can shave a bit of weight from an opposite pair of balance screws, try removing a pair of the smallest screws and see how much of a difference in makes to the rate, then you will get a better idea how much weight you need to remove.
 

David D'Apice

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Mar 22, 2012
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Wow -- that's interesting -- never heard of it --- does the lighter weight balance make the clock run faster or slower? I suppose it doesn't oscillate as much, so it will get quicker -- that's really a neat idea -- I never even thought about that.
 

dickstorer

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Oct 19, 2010
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I do not see any balance screws. So you can try making the HS a little shorter and then reset the beat. How much amplitude are you getting now?
 
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gmorse

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Hi David,

Removing weight from the balance rim will increase its frequency, but a lever escapement will tend to run faster if the amplitude is low, so that's something to look at first before removing any timing screws. Low amplitude can be caused by magnetism, hairspring rubbing or out of true in the round or flat, dirty or damaged pivots, pivot holes, jewels or endstones, chipped pallet stones, lack of freedom anywhere in the train, or a tired mainspring, to name just a few. Making irreversible changes should always be the last resort when you're absolutely sure it's the correct solution, otherwise you can just introduce more problems.

Regards,

Graham
 

ClipClock

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I dont see any timing screws either. Is the hairspring correctly through the regulator and can you see it making contact with it as it pulses?
 

gmorse

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Hi Sally,

The balance is running, so the screws are just a blur, but I think they're there. It's a good point about how the spring is acting in the index pins.

David, If it's running slow as opposed to fast, it's still worth checking the amplitude, which should be around the 270° mark. If you take a short video of the balance running you can play it back in slow motion to see what's happening. All the things I mentioned can cause problems, so they all need to be correct for the platform to run as it should. Re-pinning the hairspring would fix the slow running, but there may be something else going on. If you aren't familiar with hairsprings, go carefully, they're delicate little beasts and not necessarily easy to find a replacement.

Regards,

Graham
 
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David D'Apice

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Mar 22, 2012
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You guys are the best -- Graham, I'm going to have to check amplitude. I'll do that with the video --- all the screws are there -- and I agree, to lighten the wheel isn't the best thing historically ---- The regulator does seem to be in order -- and the spring is laying against the pin (between it and the block), so that appears in order. I've got it as fast as possible, and it's about 1/2 minute over the course of the night -- not horrible, but frustrating to see the lever way over like that. I'll check carefully at amplitude, but I'm thinking repin and re-set of beat. It's possible that the spring was re-pinned already a little too "shortly" -- I see lots of extra spring.
 

gmorse

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Hi David,

... It's possible that the spring was re-pinned already a little too "shortly" -- I see lots of extra spring. ..
That's a pretty good clue . . .

Regards,

Graham
 

Ralph

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Shorten the spring, by just relocating it's pinning. You don't have to cut it. You can do it, later for aesthetics, if you get it running correctly. You 'll have to reset the beat, after moving the spring. I wouldn't consider lightening the balance or it's screws, especially if this is the original platform.

Ralph
 

Tinker Dwight

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Oct 11, 2010
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We have seen cases where a long clean in an ulta-sonic
will weaken a hair spring. This slows the clock.

The balance wheel is designed to be least effected by
using a different strength main spring, when working correctly.
If it has good swing with the original main spring you
should go back to that.

The strength of the hair spring or amount of weight only
has a tiny effect on the amount of swing but a large effect
on the rate. I suspect that removing balance weights will
overshoot the desired weights.

If you decide to remove a weight, I recommend removing the balance wheel.
The pivots on these are extremely fragile. Any significant torque could easily
break one.

It has already been mentioned that changing the hair spring
length will require resetting the beat.
Tinker Dwight
 

David D'Apice

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Mar 22, 2012
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I'm trying to get up the nerve to shorten the hairspring --- hopefully I can get it back into proper beat afterward -- assuming I don't sneeze and lose the whole thingl Yikes. Gives me the willies just thinking about how delicate that stuff is. Do I just put a really tiny screwdriver into the collet of the hairspring and turn the wheel to bias it? Should I do it while it's assembled? I feel like a tight rope walker!
 

David D'Apice

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Mar 22, 2012
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OK -- I just dove in head first -- with headband magnifier and my best Bergeon screwdrivers -- I managed to get the cock and balance out safely, unpinned the hairspring, shortened it up a bit and re-pinned -- and then -- the triple gainer off the top diving board --- I re-set the collet so that the impulse jewel ended up between the banking pins. My first attempt at something this delicate ---- it's ticking away --- and I've moved the regulator back to the middle. Wish me luck!!! So far, I haven't managed to destroy this innocent clock!
 

Tinker Dwight

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Shortening a hair spring often takes more than you'd think. It is better
to just extend the excess spring out the back until you get it to work.
Also, you need to bend the hair spring so that it enters the regulator
without any side load ( or very little ).
I did not notice an step in the curve of the spring ( I should have noticed that ).
It might be an indication that the spring you have was a replacement.
Tinker Dwight
 

David D'Apice

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Mar 22, 2012
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Good thought dwight -- as always --- I didn't cut the spring at all -- left the extra behind -- I didn't note a step either --- we'll see what it does. It appears to be vibrating pretty happily.
 

David D'Apice

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Mar 22, 2012
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Pretty good news -- I'm not sure how sensitive the tolerances are for beat and speed, but this looks pretty good to me, assuming 18,000 is where I want to be. attachment.jpg
 

Attachments

gmorse

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Hi David,

If it stays stable at that rate, that's a gain of 1.296 seconds per day. Checking the hands will soon tell you if it is in fact an 18,000 bph movement.

Regards,

Graham
 

David D'Apice

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Mar 22, 2012
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Graham --- definitely an 18000 movement -- kept near perfect time overnight. The only wrinkle is that the strike seemed to be an hour off -- I'll have to check that pesky snail -- could be off a tooth or so! Other than that, this one has been conquered --- with everything that was wrong, the cards were against it, but it lives again for another century! That's so rewarding -- thanks everyone for all you wonderful insight!
 

Tinker Dwight

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Oct 11, 2010
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Check it at 12 and 1. If it is always shifted, you can move the hour hand.
If only off at some hour strikes, setting the motion works teeth position
usually fixes that.
Otherwise, you may have to look at the rack tail to see what could be causing
it to not measure the snail right.
 

David D'Apice

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Mar 22, 2012
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I did just as you suggested Dwight -- last night I moved the hour hand a re-assembled the clock --- the rack seems to drop into the sweet spot for each hour on the snail, so I think the teeth mesh is OK -- so far, it's run and struck correctly all day -- couldn't be more pleased to see this clock get rescued from the bonepile -- although it's been a long ride! Sometimes, the time and money aren't the drivers -- it's just fun to put history back in order like that. I have great respect for these little masterpieces! Thanks again. Consider this one solved!
 

Doug Osborne

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Jan 28, 2006
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Hold the tail of the adjustment that has the index pins. Hold it tight and move the other end that points to the adjustment scale, move it to point at the center of the scale. You will now have plenty of adjustment. Don't mess with the hair spring you will have plenty of adjustment when you relocate the scale pointer to the center.
 

David D'Apice

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Mar 22, 2012
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Fantastic -- I had no idea! Thanks Doug.
 

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