Omega 613 Sweep second stuttering

[mikepilk]

I have a problem with a stuttering/jumping second hand on an Omega 613.

The second pinion looks OK, as does the cock jewel. But as you can see in the video, with the cock removed, there's a lot of play. Is this normal?

The friction spring sits up in the air above the pinion. Should it be bent down to provide pressure when the cock is not fitted?

Is something worn or is it a setting up problem. If so,  what's the trick in getting a smoothly running second hand ?

Ta

Mike

171022154504566.avi

[Marc]

With the cock removed (as in your video) there will be a lot of play as the jewel that supports that end of the pinion is in the cock.

Also, I can't see any sign of the tension spring in any if the images. The specific function of that spring is to control seconds hand stutter so without it there will be a problem. You mention that without the cock the spring sits up in the air above the pinion, which suggests that the spring isn't actually missing, but it also suggests that the spring should sit underneath the pinion leaves so that it lifts the pinion up into the jewelled bearing in the cock thus providing the tension to control the seconds hand. I have not worked on one of these so I don't know if the spring should lift the pinion up or press it down, but either way it needs to be in contact with the pinion.

[mikepilk]

21 minutes ago, Marc said:

With the cock removed (as in your video) there will be a lot of play as the jewel that supports that end of the pinion is in the cock.

Also, I can't see any sign of the tension spring in any if the images. The specific function of that spring is to control seconds hand stutter so without it there will be a problem. You mention that without the cock the spring sits up in the air above the pinion, which suggests that the spring isn't actually missing, but it also suggests that the spring should sit underneath the pinion leaves so that it lifts the pinion up into the jewelled bearing in the cock thus providing the tension to control the seconds hand. I have not worked on one of these so I don't know if the spring should lift the pinion up or press it down, but either way it needs to be in contact with the pinion.

Good point that the spring might fit under the pinion. I hadn't thought of that - I've only come across springs that press down.

Hopefully someone will clarify that.

[anilv]

it is as Marc said.

The tension of the spring should be just enough to lightly lift the pinion and hold it against the jewel hole. Too much 'bend' and it will cause some drag. Not enough and the seconds needle will stutter.

Anilv

 

[mikepilk]

10 hours ago, anilv said:

it is as Marc said.

The tension of the spring should be just enough to lightly lift the pinion and hold it against the jewel hole. Too much 'bend' and it will cause some drag. Not enough and the seconds needle will stutter.

Anilv

 

Thanks Anilv

I need to lessen the bend - it's obviously causing drag as amplitude is down 20 deg. 

I used a small amount of 9010 to oil the pinion, jewel and tip of spring.

[anilv]

OK..you can also check the amplitude with the sweep pinion removed totally and see if that improves things. Poor amplitude can be caused by a lot of things... I usually find mostly related to mainspring, barrel pivots bear the bulk of the blame on older watches.

Anilv

[mikepilk]

7 hours ago, anilv said:

OK..you can also check the amplitude with the sweep pinion removed totally and see if that improves things. Poor amplitude can be caused by a lot of things... I usually find mostly related to mainspring, barrel pivots bear the bulk of the blame on older watches.

Anilv

I was going to say the amplitude was good. I fitted a new mainspring, and was getting 300 deg face up and down (before I fitted the date works).

Now I'm seeing 265 deg face up and 245 deg face down. I removed the date works and the numbers didn't change. 

I wonder why it's dropped so much?  I'll strip it back down and have another look under the microscope

[frenchie]

Just to make sure I understand: without the second pinion, you amplitude is 300 deg. When you add it back (with the spring and the cock), the amplitude drops to 245-265 (no hands and no dial I assume)?

[mikepilk]

34 minutes ago, frenchie said:

Just to make sure I understand: without the second pinion, you amplitude is 300 deg. When you add it back (with the spring and the cock), the amplitude drops to 245-265 (no hands and no dial I assume)?

I tested it whilst assembling - no dial/hands/date works, and with the second pinion fitted, but with the spring above the pinion instead of below.

I was happy to see 300 deg amplitude dial up and down.

A couple of days later I'm getting the reduced amplitude, even with the pinion removed (no dial/hands/date works). It's a bit puzzling as to why. I can't see anything obvious. The hairspring is absolutely flat. The timegrapher plot looks 'clean' with no odd noises

The difference dial up/down suggests it could be the balance pivots? When I came to clean it the oil was solid. One IncabIoc setting was completely stuck in solidified oil. I had to scrape the cap jewels as twice through the ultrasonic didn't clean it. I need to inspect the balance pivots under the microscope. They only got an ultrasonic clean, maybe they need more.

[anilv]

Mike..was the crown pushed back in the second time round? this can cause some drag as the watch will try to turn the winder.

Apart from that double checking the balance pivots is a good idea..could be some dirt which got dislodged and caused the drop. Also check the barrel pivots.

all the best!

Anilv

[rodabod]

Firstly, although it's counter-intuitive, you usually don't oil these friction springs. They are there to create drag, and in some cases to hold the sweep seconds pinion in place if there is no seconds pinion cock.

There should be just enough drag created to help the motion of the seconds pinion become smooth. This is needed as this is an indirectly-driven design and has some "slack" in the meshing of the seconds pinion. You should notice a slight drop in amplitude; say 5-10 degrees for example when the spring is fitted. Adjust to suit.

This is a later Omega calibre with fine pivots. The jewels and pivots must be scrupulously clean. Especially the balance pivots and towards that end of the train. Inspect the balance jewels with a high magnification loupe and look for any smears on the surface when the jewel is reflecting light. I find that dipping or rubbing with naphtha sometimes helps before going into my cleaning machine.

[mikepilk]

9 hours ago, rodabod said:

Firstly, although it's counter-intuitive, you usually don't oil these friction springs. They are there to create drag, and in some cases to hold the sweep seconds pinion in place if there is no seconds pinion cock.

There should be just enough drag created to help the motion of the seconds pinion become smooth. This is needed as this is an indirectly-driven design and has some "slack" in the meshing of the seconds pinion. You should notice a slight drop in amplitude; say 5-10 degrees for example when the spring is fitted. Adjust to suit.

This is a later Omega calibre with fine pivots. The jewels and pivots must be scrupulously clean. Especially the balance pivots and towards that end of the train. Inspect the balance jewels with a high magnification loupe and look for any smears on the surface when the jewel is reflecting light. I find that dipping or rubbing with naphtha sometimes helps before going into my cleaning machine.

Thanks for the advice.

I've just taken the balance+ jewels out. The pics are before re-cleaning. It looks like there could be some muck on the shoulder of the lower  pivot. Could be hardened oil that's worked loose. Would explain the drop in amplitude after a couple of days.

I'll clean it and see.

 

Edited October 25, 2017 by mikepilk

[mikepilk]

On 10/25/2017 at 8:55 AM, rodabod said:

Firstly, although it's counter-intuitive, you usually don't oil these friction springs. They are there to create drag, and in some cases to hold the sweep seconds pinion in place if there is no seconds pinion cock.

There should be just enough drag created to help the motion of the seconds pinion become smooth. This is needed as this is an indirectly-driven design and has some "slack" in the meshing of the seconds pinion. You should notice a slight drop in amplitude; say 5-10 degrees for example when the spring is fitted. Adjust to suit.

This is a later Omega calibre with fine pivots. The jewels and pivots must be scrupulously clean. Especially the balance pivots and towards that end of the train. Inspect the balance jewels with a high magnification loupe and look for any smears on the surface when the jewel is reflecting light. I find that dipping or rubbing with naphtha sometimes helps before going into my cleaning machine.

Well I've found out what the problem is. After re-cleaning I'm getting 290 deg amplitude face up, but less than 200 deg face down.

I noticed lots of balance end shake - the lower Incabloc sticking proud of the dial side of the main plate. When pushed flush on the dial side it sticks out far enough to snag the pallet fork. 

I've never seen an Incabloc setting that doesn't sit flush with a plate, so I assume the wrong setting is fitted?

 

Edited October 28, 2017 by mikepilk

[rodabod]

Have you tried swapping the incabloc settings over in case they were previously swapped? I can't remember if these ones match or not. 

[mikepilk]

48 minutes ago, rodabod said:

Have you tried swapping the incabloc settings over in case they were previously swapped? I can't remember if these ones match or not. 

I found some pictures which show that the Incabloc setting does sit proud of the surface on these movements (see pic). Seemed odd to me.

I adjusted the end shake and the balance is fine now. 

What was puzzling me was that I was getting good amplitude, then the next day very poor .... then good. Tracked it down to a bent center wheel. I've tried to flatten it but haven't managed to get it perfect, so I've ordered a replacement. 

 

[JohnR725]

Sometimes helpful to look at what other people are doing so you can compare. Link below someone else servicing the same movement. I've also stepped out a image from the same site which is attached showing where the spring goes.

http://watchguy.co.uk/service-omega-seamaster-136-017-calibre-613/

[mikepilk]

18 minutes ago, JohnR725 said:

Sometimes helpful to look at what other people are doing so you can compare. Link below someone else servicing the same movement. I've also stepped out a image from the same site which is attached showing where the spring goes.

http://watchguy.co.uk/service-omega-seamaster-136-017-calibre-613/

Hi John.

I always check up on what other people have posted before servicing a new movement. The Watchguy's site is especially good. That's where I clipped the above pic from ..... and where I'm getting  a replacement centre wheel !

Edited November 11, 2017 by mikepilk

[anilv]

The height of the balance jewels is determined by the interaction of the train. If the escape wheel and its pivots look unmolested, start there by ensuring the pallet fork hits the escape wheel squarely in the middle of the pallet jewels. Then check that the impulse jewel does not hit the guard pin (middle leg). It is difficult to see so you may need to remove the train and barrel bridges and associated parts to allow you to examine this. I believe the balance jewel on your watch has been moved so you would need to ensure that it is corrected here. Finally install the balance and check endshake. You have some leeway here to increase/decrease the endshake by moving the lower balance jewel but this is very minimal. The jewel on the balance cock is not adjustable. While the hole jewels and cap jewels can probably be swapped around, the settings cannot. The lower jewel is generally a friction fit and the upper is usually held by a clip.

Anilv

 

[mikepilk]

3 hours ago, anilv said:

The height of the balance jewels is determined by the interaction of the train. If the escape wheel and its pivots look unmolested, start there by ensuring the pallet fork hits the escape wheel squarely in the middle of the pallet jewels. Then check that the impulse jewel does not hit the guard pin (middle leg). It is difficult to see so you may need to remove the train and barrel bridges and associated parts to allow you to examine this. I believe the balance jewel on your watch has been moved so you would need to ensure that it is corrected here. Finally install the balance and check endshake. You have some leeway here to increase/decrease the endshake by moving the lower balance jewel but this is very minimal. The jewel on the balance cock is not adjustable. While the hole jewels and cap jewels can probably be swapped around, the settings cannot. The lower jewel is generally a friction fit and the upper is usually held by a clip.

Anilv

 

I have adjusted the lower jewel to give the right amount of endshake. From what I can see the pallet fork is sitting at the correct height.

I'm just surprised that the Incabloc setting does not sit flush with the plate. I don't remember seeing this with any other movements.

[Watchtime]

Reading with great interest...hats off for your stamina to get this right.

[anilv]

Hi Mike.. tis could have been done to correct endshake on a replacement balance staff that did not quite fit. Sometimes looking at the overall condition of the watch will give you an idea of its past.

Hopefully the new centre-wheel will solve the problem!

Anilv