Losing 5 minutes at 10 to the hour

[Martyn58]

Morning everyone!

 My chiming mantle clock has started to lose 5 minutes between the 45 minute chime and the hour chime. I’m thinking it’s something to do with the warning run for the strike?  But I don’t understand how the hands can lose 5 minutes when the pendulum is still swinging?  The clock has been running sweetly for about 2 weeks. 
 

All thoughts and suggestions appreciated!!

 

Thanks in advance … Martyn 

[nickelsilver]

No idea which movement this is, but they all have a friction setup for setting the hands. It might resemble a canon pinion from a watch, or it could be a separate wheel that fits to the center pinion and is held by a friction spring (or some others but those are the most common). Sounds to me like the friction is too low, and it's slipping when trying to move levers.

[Martyn58]

Thanks for the prompt response!  I’m a newbie but I’m learning all the time. I have read about canon pinions and thought I understood … but I’m probably missing something. 
 

It’s just past 10am, and as described the hands seemed to ‘stick’ for about 6-7 minutes just as the strike movement is going into warning. However, the clock keeps running and if left to its own devices will continue for the next hour as expected. I’ll watch it as it approaches 11am. All good fun!!

[Endeavor]

We have a specialist among us @oldhippy

Does the clock, despite the fact that the hands "stick", still strikes on time?

If the clock still strikes every hour, every 60minutes and on time (measured with a watch / another clock), than you have to look somewhere Nickelsilver suggested.

If the whole timekeeping & striking is "off" with the same amount as the hands are "off", then the running-works do see some kind of "hold-up" or "sticky" moment(s).

Edited July 8, 2023 by Endeavor

[watchweasol]

Hi is this a clock you have dismantled and re built or can you give us any circumstances leading up to the problem.  There are several factors to consider, hammer wheel, warning wheel, center wheel clutch, canon pinion . Might be a clip has come off allowing a wheel/ lever to move, so as you see there are many possibilities.  Can you also supply us with pictures of the front plate and from the sides, thank you.

[Martyn58]

1 hour ago, Endeavor said:

Does the clock, despite the fact that the hands "stick", still strikes on time?

Thanks for your help! Yes, the clock chimes and strikes correctly according to the position of the hands. Since my first post I’ve allowed it to run unhindered and it lost the 5-6 minutes at 10 minutes to the hour as expected … but I haven’t adjusted it since and it remains 5-6 minutes slow despite passing through ‘10 minutes to the hour’. 

31 minutes ago, watchweasol said:

There are several factors to consider, hammer wheel, warning wheel, center wheel clutch, canon pinion .

I haven’t disassembled this movement yet. I did learn how a mainspring barrel can be removed without separating the plates. The clock has been working well for a couple of weeks.  The ‘loss of time keeping’ at 10 minutes before the hour started a couple of days ago. 
 

I don’t have a good photo of the movement between the plates atm. When I get an opportunity to use the ‘dining table - workbench’ I’ll remove the movement and take a closer look at the warning run on the strike side. 
 

I’ve not yet worked on a chiming clock … but I have learned a Smiths Enfield strike clock. All good fun !  Thanks for helping … I’ll keep you posted. 

[watchweasol]

Hi. One thing looking at the plate is the hands fitting on the center wheel, are they original ?  Check they are not loose and the minute wheel can not slip forwards and is stil held by the clip it looks sloppy maybe ok and the hands are not loose on the boss. All the pins seem to be in ok. Start with the simple things first as they are too easy to overlook.  When this occurs I take it that the clock continues to run ok    Does each subsequent hour do the same. And does it accumulate another 10 mins,  now become 20 mins 

A view of the rear plate and any markings if you could please

[oldhippy]

It sounds like the rivet in the center of the minute hand has worked loose. Can you check that first. Then get back to me.

 

 

Edited July 8, 2023 by oldhippy

[Martyn58]

3 hours ago, watchweasol said:

Check they are not loose and the minute wheel can not slip forwards and is stil held by the clip it looks sloppy maybe ok and the hands are not loose on the boss.

The movement is back in its case now with hands fitted correctly. I don’t think the minute wheel can slip forwards … but I’ll know for sure when I get a chance to remove the movement. 
 

Small update though : the loss of 5-6 minutes isn’t cumulative. If I allow it to run 5-6 minutes behind the actual time, it runs through the next chime cycles perfectly for hours. However, if I set it to the correct time , it loses the 5-6 minutes again at the approach to the top of the hour ( when setting up the warning run ). 

58 minutes ago, oldhippy said:

 

It sounds like the rivet in the center of the minute hand has worked loose. Can you check that first. Then get back to me.

 

Hello again!  Thanks for your suggestion … I’ll be able to check tomorrow. Will get back to you then. 

3 hours ago, watchweasol said:

A view of the rear plate and any markings if you could please

 

[watchweasol]

Hi so the time differential is no accusative, then check that the minute hand is not loose on its boss like I said, as it’s travelling up though 9 the hand drops a little then when through 12 going down it pick it up again as it pivots on the boss. Take off the minute hand and put a square file handle through the boss, hold  the hand close to the boss and try to turn it . If it’s slack it will need re riveting if not we are looking for something else.

[Martyn58]

12 hours ago, watchweasol said:

Take off the minute hand and put a square file handle through the boss, hold  the hand close to the boss and try to turn it . If it’s slack it will need re riveting if not we are looking for something else.

Morning! I’m pretty sure that the hand is securely riveted. Looks and feels good to me. 
The movement is out of the case right now and I can feel quite a lot of resistance as the rack hook is lifted to free the gathering pallet. 
For sure this movement has not been serviced since the 1980s and possibly not often before then either. So please excuse the dirty condition. 

14 hours ago, oldhippy said:

rivet in the center of the minute hand has worked loose. Can you check that first. Then get back to me

Morning! I’ve checked that and it’s not the problem. I’ve got the movement out of the case now. When I manually advance the hands through an hour I can feel a greater than usual resistance as the lifting lever tries to lift the rack hook to free the gathering pallet. Can that cause the clutch on the centre wheel to slip?

[watchweasol]

Hi  good morning to you,  so the hand is fixed ok. For the clutch to slip needs quite a lot of force and the tension would have an effect on the time keeping as each time it went through the hour it would loose time. Try removing the hands, hour wheel  check the other wheels , minute wheel, snail cam. then try the lifting lever on its own holding the strike train stationary by blocking either the fly or warning wheel, the lifting lever lift and drop freely.   Check all the removed wheels for wear/damage and refit.  Now whilst blocking the srrike train hold the fly or block warning wheel and see if you get the same resistance as before.

[oldhippy]

If the movement is in such a dirty condition then it needs a complete clean and checking for wear. I'm not surprised about the hand because I would expect to gain about the same amount of time from just past the 12 on its coming down as it travels up. When they start playing up that is sign it needs a good checking over.  

[Martyn58]

1 hour ago, watchweasol said:

Check all the removed wheels for wear/damage and refit.  Now whilst blocking the srrike train hold the fly or block warning wheel and see if you get the same resistance as before.

It was quite difficult removing the broken taper pin to remove the minute wheel, but I got there. Despite years of ‘dirt’ I think everything looks ok. I’ve lubricated the contact points of the lifting lever, gathering pallet etc and it seems a lot easier than before. For sure the whole thing needs a complete service but that’s above my pay grade atm. What’s more, I like to see and study a working movement before I attempt a disassembly. As I get more familiar with it I’ll find the confidence to disassemble further. 

1 hour ago, oldhippy said:

If the movement is in such a dirty condition then it needs a complete clean and checking for wear.

I agree completely!  But it’s the first time that I’ve had a chance to look at a chime mechanism and my only other movement experience to date is a striking Smiths Enfield. I’ll figure it out slowly. One step at a time. Actually, I bought what looks to be a very similar clock off eBay this week that isn’t quite working. It will be my practice clock. Then I’ll feel more confident servicing this one which belongs to my father in law. 

[oldhippy]

We are here to help you with what ever. 

[watchweasol]

Hi if that one is a family clock makes sense to study it and be confident so practising on a spare sounds like a good idea that way you get experience and the tools you will require.  Come back with any questions when on your practise clock.   

Hi attached are a few pics that put names to the parts in case you are not sure.

[Martyn58]

2 hours ago, watchweasol said:

practising on a spare sounds like a good idea

Exactly!  That’s what I did with a couple of watch movements. Thanks for the illustrations … really helpful!!

I’d be interested to know what you think of the photo … is it the canon pinion crimped onto the centre wheel arbor? And how would you go about removing it when the time comes?

4 hours ago, oldhippy said:

We are here to help you with what ever. 

Thanks! I appreciate it. 
I have a question re pendulum bob. Where there are 2 nuts on the rod I presume the smaller is to support the bob at an approximate height, and the other larger nut is for very fine adjustment … raising or lowering the centre of gravity of the assembly? In this photo I would say they’re the wrong way around?

[LittleWatchShop]

2 hours ago, watchweasol said:

attached

Thanks for this. I have yet to memorize all of the levers and such on clocks!!

[watchweasol]

Hi the canon pinion/ star cam are pressed on to the center wheel which is a tapered shaft. The star cam has either.   2.  Projections, for the half hour/ hour strike.  Or. 4 for one for each quarter the longer on in each case is for the hour and lifts the long lever higher than the quarters to release the strike from warning state to strike.  There are different opinions regarding removing it some say if it is not worn or needs bushing Lea it alone others say remove it but in the latter case I made a tools to take it off a nd put it back, but care needs to be taken not to bend/warp the shaft.

regarding the pendulum  most have just the one nut for regulation but there is no reason not to use a second as a lock nut depends on how slack the first is on the shaft.

 

[LittleWatchShop]

36 minutes ago, Martyn58 said:

Exactly!  That’s what I did with a couple of watch movements. Thanks for the illustrations … really helpful!!

I’d be interested to know what you think of the photo … is it the canon pinion crimped onto the centre wheel arbor? And how would you go about removing it when the time comes?

Thanks! I appreciate it. 
I have a question re pendulum bob. Where there are 2 nuts on the rod I presume the smaller is to support the bob at an approximate height, and the other larger nut is for very fine adjustment … raising or lowering the centre of gravity of the assembly? In this photo I would say they’re the wrong way around?

Looks like the Canon pinion could slip while the chime cam still maintains accurate.

I have never seen two nuts on a pendulum. Looks like a hack to me. But, I am an amateur with limited experience.

Edited July 9, 2023 by LittleWatchShop

[oldhippy]

The two nut on the pendulum might be because the first ones thread might be worn so the second was added. I prefer not to remove the cannon pinion unless  you have wear. 

[Martyn58]

Morning all !  Short update : I did as much as I dared ( just cleaning and a little oil ) and re-cased the movement. It certainly helped but only for a day or so. Right now the clock is not gaining or losing over a week or so, but it is about 10 minutes behind Greenwich. If I set it correctly it’ll ‘struggle’ next time it gets to the top of the hour and end up 7-10 minutes behind Greenwich again.  Then it’ll happily stay like that for days. 
 

Anyway, I managed to buy a very similar movement from eBay and am currently servicing that one ( it was sold as not working and holds no sentimental value to me so I’m happier working on it ).

Since it’s pretty much the same movement I’d like to add a couple of questions here. 1. Should the chime locking plate simply pull off the arbor after the two locking screws have been removed?  And 2. should the rack also pull off the post after the taper pin has been removed?

Both seem very reluctant to budge. 
Thanks in advance as always!

[oldhippy]

Number 1 it should have a screw look between it or look behind it. The rack will just pull off but in the photo it looks like a pin in the hole which you need to remove if you can't get hold of it knock it out, I used another pin or a punch. 

[Martyn58]

4 hours ago, oldhippy said:

Number 1 it should have a screw look between it or look behind it. The rack will just pull off but in the photo it looks like a pin in the hole which you need to remove if you can't get hold of it knock it out, I used another pin or a punch.

Yes. I removed the screws of the chime locking plate but it didn’t want to budge … and I’m not sure if it’s normal to pry it off?

And yes, I removed the taper pin but same issue. It’s the first time I’ve come across this … on my Smiths strike mechanism the rack lifts off easily. 
Regardless, I left them in place and was still able to separate the plates and remove all but those 2 wheels and the going centre wheel.  Not ideal perhaps, but I’ve been able to get everything clean. 

As for the original problem of this thread … I’ve found the problem. Matthew Read explains it in YT video Open Clock Club #043. He explains how a going train can keep running while the friction clutch on the centre wheel slips for some minutes and then grips sufficiently to continue turning the hands. 
 

So I need to learn how to remedy that problem

All suggestions and advice welcome!

[oldhippy]

Number 1 is normally held with a screw sometimes it can be a small grub screw. I have never come across a movement where you have to force it off. 2 The rack can you put a fine wire through the hole, I still think a bit of the pin is preventing you from taking the rack of. Can you take clear close up photos of both  and make one so I can see number 1 from the side and behind it.