La Joux Perret G100 stopped on impact - Why?

[tomh207]

11 minutes ago, Neverenoughwatches said:

I can varify without doubt that the root cause was a rather hard knock on the edge of a table ( I definitely have it right this time ) As to the remaining issue please let us know what your watch guy finds. Its ok you can just tell me i can keep secrets.

I have to disagree Rich, this was a customer statement which has to be taken silently with a liberal pinch of salt. I agree that it has had a shock but it would likely be of a bigger magnitude than bumping it off a table. 
 

Tom

[Neverenoughwatches]

2 minutes ago, Microbrandowner said:

This opens a can of worms though - our watch cases are made of 316L Steel, 10 ATM water tightness, Sapphire crystals. We don't use plastic movement holders, and only use metal movement holders. Second - the movement is LJP G100. I am confident it is built with some form of shock resistance - either Novodiac, or Incabloc. The watches are built well - and it is shocking (no pun intended) to hear that a hard knock on the table could cause the watch to come to a complete stop. Could a knock to the table or a door-knob cause the movement to overbank? Are modern-day Swiss movements that easy to break? OTOH, the speck of dust argument is more likely, and explains why the watch would stop.

 

I think thats a hard question to answer, though the shock protection that we have been discussing is different to the one you mention here which resists shock to cause pivot damage. We were discussing escapement, possible that the safety clearances were slack allowing some kind of overbank. I'm far from an expert but i generally do think logically, i can almost guarantee if i shake the watch on my wrist hard enough i can cause enough damage to make it stop. An impact that you describe may have been enough but neither you or anyone here were witness to it. A hard sudden jolt to a dead stop , could it cause the watch to stop and cause damage ?  It certainly looks that way

5 minutes ago, tomh207 said:

I have to disagree Rich, this was a customer statement which has to be taken silently with a liberal pinch of salt. I agree that it has had a shock but it would likely be of a bigger magnitude than bumping it off a table. 
 

Tom

Yep i can completely agree with you Tom , a decent quality watch that is set up correctly would need more than just a bump.

This is a loose example Tom , different watch different quality . A non working Timex i bought about a year ago,  it had over banked so i removed the balance put it back in , all hunky dorey for about a month of wristwear, it became my everyday wear for work. Then one day i had to break in through a front door for a customer, about 20 mins of hard drilling a 5 lever lock out. When I got home i noticed my Timex had stopped, on inspection the impulse had again made its way onto the wrong side of the fork. It hasn't done it since, i haven't drill any more locks out since either. Standard of watch plays a big part , factories can churn out friday movements that are not quite there. 

35 minutes ago, Microbrandowner said:

This opens a can of worms though - our watch cases are made of 316L Steel, 10 ATM water tightness, Sapphire crystals. We don't use plastic movement holders, and only use metal movement holders. Second - the movement is LJP G100. I am confident it is built with some form of shock resistance - either Novodiac, or Incabloc. The watches are built well - and it is shocking (no pun intended) to hear that a hard knock on the table could cause the watch to come to a complete stop. Could a knock to the table or a door-knob cause the movement to overbank? Are modern-day Swiss movements that easy to break? OTOH, the speck of dust argument is more likely, and explains why the watch would stop.

 

Can understand your concern,  companies rely on reputation,  thrive on a good one , sink with on a poor one. This issue is something you would want to get to the bottom of.  One suggestion i can make , initial inspection of a non working watch, without making any changes to the movements situation, look , look and look again very closely. I'm not suggesting your guy didn't do that , but an overbank can be easily ruled out, i did mention at the start that in this case it was an unlikely cause as it would be easily found, even if just caught up slightly. Be good to find out what damage or change has happened to make the tg freak out , that will at least point you in some direction instead of no direction .

[Nucejoe]

  @Microbrandowner   In case this is a culprit with LJP G100 ,  More detailed, accurate, tech investigation is needed done and analysed to propose a solution in improving your product. 

 

Question:

Do movements come to you all assembled?  

 

Rgds

 

 

 

[Microbrandowner]

36 minutes ago, Nucejoe said:

Question:

Do movements come to you all assembled?  

Yes, movements always come to brands fully assembled, unless there is an explicit request from the brand. In our case, we get movements fully assembled and ready to be cased up.

2 hours ago, Neverenoughwatches said:

Can understand your concern,  companies rely on reputation,  thrive on a good one , sink with on a poor one. This issue is something you would want to get to the bottom of.  One suggestion i can make , initial inspection of a non working watch, without making any changes to the movements situation, look , look and look again very closely. I'm not suggesting your guy didn't do that , but an overbank can be easily ruled out, i did mention at the start that in this case it was an unlikely cause as it would be easily found, even if just caught up slightly. Be good to find out what damage or change has happened to make the tg freak out , that will at least point you in some direction instead of no direction .

It is likely our watchmaker missed the overbank and slightly adjusted the balance/pallet fork when he opened the watch. Now that the customer watch is being sent back with a brand new movement, we will look into this movement closely to see if there's anything we need to escalate with LJP as @Nucejoe suggested.

[VWatchie]

15 hours ago, Neverenoughwatches said:

in normal running circumstances H, but the impact may have damaged a safety feature allowing an overbank to occur. Without a gaurd pin tracking the safety roller to bump off, a quick flick of the wrist can trigger an overbank.

Anything is indeed possible, but considering the safety features put in place on this quality movement to precisely combat overbanking, it is not one of the more likely scenarios.

15 hours ago, Neverenoughwatches said:

A disney song from Frozen now springs to my mind   "Let it go, let it go"

Indeed! Better bring out the Sherlock magnifying glass and take it apart.

14 hours ago, Microbrandowner said:

4) The cause was none of the above, the entire movement has to be taken apart and inspected to identify root cause.

Yes, as there could be many other reasons or a combination of reasons.

15 hours ago, Microbrandowner said:

So a thorough investigation is required. I will ask our watchmaker to do this and come back with any observations. 

That would be very interesting. Thanks!

14 hours ago, Microbrandowner said:

Second - the movement is LJP G100. I am confident it is built with some form of shock resistance - either Novodiac, or Incabloc.

As far as I can tell it's equipped with the KIF anti-shock system. It is the very same system used in millions of Rolex movements. These days, Rolex has its patented anti-shock system named Paraflex but that's a different story. Anyway, if KIF was good enough for Rolex, it's good enough for LJP. So yes, no problem there.

14 hours ago, Microbrandowner said:

Could a knock to the table or a door-knob cause the movement to overbank?

That is highly unlikely as it's been designed and thoroughly tested to combat overbanking.

14 hours ago, Microbrandowner said:

Are modern-day Swiss movements that easy to break?

No, they are generally speaking very rugged. Still, it's a fine balance between making a movement precise (Swiss) and rugged. If you want a movement that can take a beating like no other I'd suggest a Russian Vostok movement calibre 2415 or 2416B. Those movements are on the other hand not very precisely built so that's a trade-off and the watch would no longer be Swiss.

My 15-year-old son (who can be pretty wild) has been abusing my Helson skin diver watch (built like a hockey puck) for six months now (Miyota cal. 9015) and put quite a few dents on the case (soon time to repolish) but it's still working perfectly.

[Geotex]

I'm not familiar with the movement, but it was interesting to read up on. It would seem that a 4Hz movement with a 68hr power reserve kept on full wind by the automatic works could certainly be developing significant force through the power chain that could cause something to go awry in the escapement if given a severe shock!

You say you have a watchmaker that looked it over but remained stumped, so that would probably mean this is a moot point but I see that it is a hacking movement. If the balance stop lever became dislocated from its normal location as a result of a shock that transmitted along the crown/stem, it could stop the balance but then might settle back into its normal position when the stem and winding works were manipulated as part of letting down the power. Again, I don't know this particular movement, but in some those levers are very thin and sit in shallow recesses.

[mehm]

Hello everyone 

I will start with my intro first 

I'm mehmood I'm 23 years old 

A watchmaker having a work experience of 5 year I'm not a very professional but a decent and enthusiastic in technical operation loved to find the problems and figure out the problems. 

 

Okay LA JOUX PERRET G100 stopped from impact  WHY ? 

so the answer is OVERBANKING 

1 When the watch has the more (OVERWINDING)power reserve amplitude it cause the hairspring to hit the escape lever TWICE i.e ( touching outside of pallet fork ) 

2 If the barrel Mainspring releasing the power in the gear wheel too much or two early due to (over powered OR over greasing in the main spring ) it lose the the friction and tension of mainspring to early,

what it does is it pushed the pallet fork faster then usual, after the hairspring roller jewel hit the escape wheel outside of the pallet and more often when the amplitude goes to medium level in between of 170-215 amplitude it get stucked between the pallet fork 

A person who doesn't know what is causing the problem in the watch ( he'll wind the watch again ,again he'll shake the watch it will start to work again for around 10-15 sec again and it stopped back in outside of the pallet fork 

No matter how much time you wound up it won't work correctly but over winding can start the watch back again 

So here we are back again in issue of OVERBANKING 

As you have mentioned that you watchmaker took out the balance and released the power reverse and fixed it back, wound up normally and started to work 

Here is thing to fix it if same things is happening again again 

1 : check mainspring power ( BY REMOVING THE BALANCE AND THE PALLET FORK IT WILL RELEASE ALL THE POWER FROM WATCH) 

So you got to know that the watch owner had over winded the watch 

You can placed those parts back in watch and start to monitoring the watch 

2 REPLACE BARREL MAINSPRING 

sometimes the power of the mainspring lose it friction or lose it shape that cause the gear wheel to work in unusually and stop the hairspring roller jewel stuck in between pallet fork Overwinding can stress the watch's components, which can affect its accuracy 

That's it 

I hope that I was able to solve your questions and the reasoning correctly 

 

[Mercurial]

Hi Mehmood, and welcome to the forum!

There are some misunderstandings in what you’ve written, I hope that the information below is helpful.

It is considered bad practice to let down the power in the mainspring by removing the balance and pallet fork. 

This releases the power in an uncontrolled manner, and it can cause damage to the watch.

The train of wheels is not designed cope with a sudden release of power, and the rapid acceleration of the escape wheel as you remove the pallet fork can cause a destructive collision between the pallet jewels and the escape wheel teeth. 

Sometimes the pallet fork will move as you lift the pallet fork bridge, unlocking the escape wheel with the pallet fork still in close proximity, which can chip the pallet stones or damage the escape wheel.

A watch with excessive amplitude can result in the roller jewel hitting the outside of the fork horns as you describe, which is known as rebanking or knocking. 

A shock to a watch that accelerates the balance wheel can also cause the roller jewel to knock, but this behaviour will stop once the shock stops, the amplitude will return to normal and the watch should run properly again unless the shock was strong enough to cause physical damage, such as a broken roller jewel.

Overbanking, or the escapement going ‘out of action’ is a different condition, and occurs when the roller jewel ends up stuck on the wrong side of the pallet fork. 

A watch that is out of action will only start running again after the balance is removed and replaced in the watch with the roller jewel on the correct side of the pallet fork. 

A shock should not cause a watch to go out of action as the result of a shock unless the safety action of the escapement is set up incorrectly. 

Finally, you cannot overwind a watch, unless you wind it to the point that it is fully wound, the winding crown comes to a hard stop and you apply brute force to the crown in an attempt to wind the watch further.

Overwinding in the sense that the word is usually used doesn’t exist. 

Best Regards,

Mark

[VWatchie]

Well written @Mercurial! 

[mehm]

16 hours ago, Mercurial said:

Hi Mehmood, and welcome to the forum!

There are some misunderstandings in what you’ve written, I hope that the information below is helpful.

It is considered bad practice to let down the power in the mainspring by removing the balance and pallet fork. 

This releases the power in an uncontrolled manner, and it can cause damage to the watch.

The train of wheels is not designed cope with a sudden release of power, and the rapid acceleration of the escape wheel as you remove the pallet fork can cause a destructive collision between the pallet jewels and the escape wheel teeth. 

Sometimes the pallet fork will move as you lift the pallet fork bridge, unlocking the escape wheel with the pallet fork still in close proximity, which can chip the pallet stones or damage the escape wheel.

A watch with excessive amplitude can result in the roller jewel hitting the outside of the fork horns as you describe, which is known as rebanking or knocking. 

A shock to a watch that accelerates the balance wheel can also cause the roller jewel to knock, but this behaviour will stop once the shock stops, the amplitude will return to normal and the watch should run properly again unless the shock was strong enough to cause physical damage, such as a broken roller jewel.

Overbanking, or the escapement going ‘out of action’ is a different condition, and occurs when the roller jewel ends up stuck on the wrong side of the pallet fork. 

A watch that is out of action will only start running again after the balance is removed and replaced in the watch with the roller jewel on the correct side of the pallet fork. 

A shock should not cause a watch to go out of action as the result of a shock unless the safety action of the escapement is set up incorrectly. 

Finally, you cannot overwind a watch, unless you wind it to the point that it is fully wound, the winding crown comes to a hard stop and you apply brute force to the crown in an attempt to wind the watch further.

Overwinding in the sense that the word is usually used doesn’t exist. 

Best Regards,

Mark

hi @Mercurial thank you so much for your help! your explanation really clarified the concept for me, and i appreciate your patience in making sure i understood it correctly, from past years when the watches having the same issues were handed to me to fix the roots cause of the problem ,i did all this method and i'm grateful for your willingnesss of your knowledge and help me improve my understanding