Installation of pallet fork and pallet bridge on ETA 2824-2

[ifibrin]

Does anyone have any tips on installing the pallet fork and pallet bridge on the ETA 2824-2?

I find it really difficult to see if the upper pivot of the pallet fork is in the jewel hole of the pallet bridge when tightening the screws of the pallet bridge, and it seems like the pallet bridge itself moves even when applying pressure with pegwood; it can tilt to one side before the screws are secured.

As a result, I have broken the upper pivot of the pallet fork, although I did manage to unassemble and reassemble the movement twice before this happened. Very frustrating, since the rest of the movement is very easy to install.

[oldhippy]

Have you tried a stronger eye glass . Sorry to say but it's the old saying practice makes perfect. There is no trick that I know of. 

[Watcher]

An inspection microscope is my solution and a very worthwile investment.

[clockboy]

I have poor eyesight and double check alignment with a microscope. 

[HSL]

I think it is a classical mistake to push down the fork bridge to hard too soon when installing the pallet fork.

One just has to have patience and work it in, I use a sharp peg wood to wiggle it gently into place with a minimal tension on the bridge. If you push to hard too soon you sure will break the pivot. A too strong lupe will not let you work with the pallet fork controlled enough, I just use a nr 3 or nr 5. You can check the alignment is okay with a stronger lupe/microscope before screwing the bridge down properly After some practice with scrap movements I’m sure you get it in place within seconds.

[Klassiker]

Go slowly and check often. Get the pivots in place and press the cock down with pegwood. Check the fork doesn't wobble. Put the screws in while holding the cock down with the pegwood, but do not tighten them. Check the function again. Put some tension in the mainspring, and check the fork snaps back and forth. Turn the screws until you feel the slightest resistance. Check the function. Tighten the screws. Check a final time. Everyone has their own variation on this routine, but the basics are small steps interspersed with frequent checks.

[ifibrin]

Actually, getting the pallet fork pivot in place isn’t the hard part, but getting it to stay in place while holding the pallet bridge down with pegwood and tightening the screws is the most difficult.

I also realized that if you tighten the pallet bridge too much sometimes the pallet fork won’t move, but the pivots are still fine! Making the screws a bit looser then retightening sometimes the pallet fork will move freely which is a real mystery to me.

[ifibrin]

21 minutes ago, Klassiker said:

Go slowly and check often. Get the pivots in place and press the cock down with pegwood. Check the fork doesn't wobble. Put the screws in while holding the cock down with the pegwood, but do not tighten them. Check the function again. Put some tension in the mainspring, and check the fork snaps back and forth. Turn the screws until you feel the slightest resistance. Check the function. Tighten the screws. Check a final time. Everyone has their own variation on this routine, but the basics are small steps interspersed with frequent checks.

When I press the pallet bridge with pegwood the bridge can sometimes have a slight tilt, and even though the pallet fork pivots are in, the pallet fork doesn’t move freely.

[Nucejoe]

 I concur with Klassiker, furthure to his advice, if you are at a point to fully tighten the screw, you are close enough to test if pivot is in before you do tighten, pivot will not slide about if its in. 

 Keep pushing down on fork cock, whilst testing if you can lift one side of the fork by the horn, you can also move the pivot ( if its not in) by working through the fork horn until it drops in, 

 ""slowly tighten the screw""     at final stages

 ""and check often.""

28 minutes ago, ifibrin said:

the pallet fork doesn’t move freely.

Then its not in.

29 minutes ago, ifibrin said:

When I press the pallet bridge with pegwood the bridge can sometimes have a slight tilt, and even though the pallet fork pivots are in.

Put the screw in but not fully tighten, this to get the locatating pins in. slight tilt before fully tightening the screw is normal, tighten when the nudge test is possivtive.

[ifibrin]

7 minutes ago, Nucejoe said:

 I concur with Klassiker, furthure to his advice, if you are at a point to fully tighten the screw, you are close enough to test if pivot is in before you do tighten, pivot will not slide about if its in. 

 Keep pushing down on fork cock, whilst testing if you can lift one side of the fork by the horn, you can also move the pivot ( if its not in) by working through the fork horn until it drops in, 

 ""slowly tighten the screw""     at final stages

 ""and check often.""

Then its not in.

Put the screw in but not fully tighten, this to get the locatating pins in. slight tilt before fully tightening the screw is normal, tighten when the nudge test is possivtive.

What do you do if the pallet fork has been able to swing freely while you are slowly tightening, but at the last moment it can’t swing? That has happened to me before.

Do you just loosen the screws a bit and hope for the best? Then repeat the entire process?

[HectorLooi]

I find that checking the pallet by snapping it left and right is not a good enough test. Sometimes the pallet can appear to be in place when moving it sideways, but the upper pivot might not be in the hole. The acid test is to use a small oiler and press down then lift the arm of the pallet. If it moves, it means the pivot is not in the hole.

Practice, good lighting and magnification. Less caffeine and alcohol helps too.

[JohnR725]

1 hour ago, HSL said:

think it is a classical mistake to push down the fork bridge to hard too soon when installing the pallet fork.

 

20 minutes ago, ifibrin said:

What do you do if the pallet fork has been able to swing freely while you are slowly tightening, but at the last moment it can’t swing?

pallet forks are always a pain. You want to go slow gently push down on the plate then look at the pallet fork and make sure it looks like it's parallel to the main plate is easy to get it off a little bit then push down and break the pivot off. Once everything looks like is right you could also gently push down on the plate when you're tightening the screw so the thing doesn't move around. Then any time you're tightening something and whatever it is quits moving definitely stop before you break something.

[ifibrin]

45 minutes ago, JohnR725 said:

 

Then any time you're tightening something and whatever it is quits moving definitely stop before you break something.

So when it stops moving, you loosen the screws and try moving the pallet fork again? 

Edited July 3, 2021 by ifibrin

[Nucejoe]

2 hours ago, ifibrin said:

What do you do if the pallet fork has been able to swing freely while you are slowly tightening, but at the last moment it can’t swing? That has happened to me before.

Do you just loosen the screws a bit and hope for the best? Then repeat the entire process?

So you are likely to have inadequate end shake on fork arbour, If you are sure both pivots are in jewel holes and fork stops swinging freely at the last moment, that means jewels are pushing on pivot shoulders.

JEWELS SHOULD TO BE MOVED APART to create .02mm end shake. 

 

Good luck.

 

[ifibrin]

2 hours ago, Nucejoe said:

So you are likely to have inadequate end shake on fork arbour, If you are sure both pivots are in jewel holes and fork stops swinging freely at the last moment, that means jewels are pushing on pivot shoulders.

JEWELS SHOULD TO BE MOVED APART to create .02mm end shake. 

 

Good luck.

 

I would be inclined to agree with you, but this movement had a healthy amplitude (300deg) and variation (+2 to +7) over different positions before I disassembled it, and the pallet fork was moving freely in the default state out from the ETA factory (the pallet bridge screws were also installed tight). Furthermore, after the two times I unassembled and reassembled it, the amplitude and positional variation was unchanged. This doesn't seem to indicate inadequate end-shake for the pallet fork.

I only observed that the pallet fork would sometimes not swing freely at some stage in the reassembly (although I only did this twice) of the pallet bridge, but if I loosened the screws, and re-tightened, the pallet fork would swing freely. Once I managed to get the pallet fork to swing freely with the pallet bridge screws fully tightened, I moved on to install the balance cock.

What I thought could have happened is that during the tightening of the pallet bridge screws, the pallet bridge got somehow slightly askew/tilted on the guide pins due to uneven tightening, which caused the jewel to rub on the shoulder of the pallet fork pivots. Then, loosening the pallet bridge screws and then re-tightening allowed the tilt to be corrected, so that the pallet bridge is flush to the mainplate.

It is also possible that the pallet fork pivot could have slipped out of the jewel because I didn't maintain enough pressure with pegwood on the pallet bridge. The two times I managed to reassemble the movement successfully I kept checking the pallet fork freedom with each turn of the pallet bridge screws, and if the pallet fork couldn't move freely I loosened the screw and tried to see if the pivot was in the jewel after that. Then I proceeded tightening the pallet bridge screws again. However, this process took up half of the total time I spent assembling the movement so the third time I did it I didn't check pallet fork freedom as thoroughly while tightening the pallet bridge screws. That's when the pallet fork pivot broke.

 

[ifibrin]

5 hours ago, HectorLooi said:

I find that checking the pallet by snapping it left and right is not a good enough test. Sometimes the pallet can appear to be in place when moving it sideways, but the upper pivot might not be in the hole. The acid test is to use a small oiler and press down then lift the arm of the pallet. If it moves, it means the pivot is not in the hole.

Practice, good lighting and magnification. Less caffeine and alcohol helps too.

Could you explain this process of testing the pallet fork freedom a bit more? Would moving the pallet fork in this way with an oiler break the pivots, or distort the pallet arms?

[HectorLooi]

8 minutes ago, ifibrin said:

Could you explain this process of testing the pallet fork freedom a bit more? Would moving the pallet fork in this way with an oiler break the pivots, or distort the pallet arms?

With a fine oiler, like a red or black one, the tip is so fine that it is unlikely to be able to break the pivots. Anyway, we're talking about being very gentle here. 

Refitting a pallet fork is not really difficult. Make sure that you have the fork the right way up. Using your tweezers, hold it by the arbor and seat the bottom pivot into the jewel hole. Try to get it as upright as possible, making sure that the pallet jewels are in the same plane as the teeth of the escape wheel. Next, carefully position the pallet bridge/cock over the fork and hover above it, trying to align the jewel over the upper pivot and aligning the screw hole and locating pins as well. Then lower it. Sometimes you'll get a "hole-in-one". If not, use a pegwood stick to apply gentle downwards pressure on the bridge/cock. Then using your fine oiler, gently nudge the fork till you feel the plate drop home. While maintaining pressure on the plate, get one of the screws in but only tighten it with the slightestamount of force. Get the second screw in a similar manner. Then test the fork by moving it left and right, then up and down. If everything feels right, tighten the screws a little more and test again. I everything is good then tighten it fully.

With good lighting and sufficient magnification, you should be able to refit a pallet in less than a minute. I recently became proficient in using a stereo microscope and I have to admit that it makes everything so much easier.

Maybe you could start practicing on pocket watches first, as the pivots of a pocket watch are more robust. Then advance to Russian watches, as their pivots are really strong.

Nobody gets it the first time. Practice until it becomes second nature. Good luck!

[ifibrin]

10 minutes ago, HectorLooi said:

With a fine oiler, like a red or black one, the tip is so fine that it is unlikely to be able to break the pivots. Anyway, we're talking about being very gentle here. 

Refitting a pallet fork is not really difficult. Make sure that you have the fork the right way up. Using your tweezers, hold it by the arbor and seat the bottom pivot into the jewel hole. Try to get it as upright as possible, making sure that the pallet jewels are in the same plane as the teeth of the escape wheel. Next, carefully position the pallet bridge/cock over the fork and hover above it, trying to align the jewel over the upper pivot and aligning the screw hole and locating pins as well. Then lower it. Sometimes you'll get a "hole-in-one". If not, use a pegwood stick to apply gentle downwards pressure on the bridge/cock. Then using your fine oiler, gently nudge the fork till you feel the plate drop home. While maintaining pressure on the plate, get one of the screws in but only tighten it with the slightestamount of force. Get the second screw in a similar manner. Then test the fork by moving it left and right, then up and down. If everything feels right, tighten the screws a little more and test again. I everything is good then tighten it fully.

With good lighting and sufficient magnification, you should be able to refit a pallet in less than a minute. I recently became proficient in using a stereo microscope and I have to admit that it makes everything so much easier.

Maybe you could start practicing on pocket watches first, as the pivots of a pocket watch are more robust. Then advance to Russian watches, as their pivots are really strong.

Nobody gets it the first time. Practice until it becomes second nature. Good luck!

Thanks for the well thought reply.

The problem is that while its easy enough to get the pallet fork lower pivot into the jewel, the upper one is more tricky. Furthermore, the pallet fork always slants to rest on the guard pin. Even when I get the pallet fork upper pivot into the pallet bridge jewel, when I tried flicking the fork with my tweezers (maybe this was the mistake!), the pivot can jump out of the jewel!

I have to add that I have only faced this pallet fork pivot problem with the 2824-2, the ETA 7001 pallet fork and pallet bridge was a breeze in comparison with this!

In any event I will have to wait for my replacement pallet fork to arrive in Singapore from Cousinsuk!

Edited July 3, 2021 by ifibrin

[HectorLooi]

27 minutes ago, ifibrin said:

!In any event I will have to wait for my replacement pallet fork to arrive in Singapore from Cousinsuk!

Hey! Are you from Singapore? I'm also from Singapore. 

[ifibrin]

8 minutes ago, HectorLooi said:

Hey! Are you from Singapore? I'm also from Singapore. 

Yeah, I'm from Singapore too. Nice to see someone else from SG on WRT.

Everytime you break something and need a part you end up having to wait a long time (ok, maybe 7 to 10 days) for replacement parts to arrive from overseas, which really kills the mood. Surprisingly, parts from UK (specifically CousinsUK or HS Walsh) come faster than from elsewhere like China.

Edited July 3, 2021 by ifibrin

[ifibrin]

On 7/3/2021 at 11:40 PM, HectorLooi said:

With a fine oiler, like a red or black one, the tip is so fine that it is unlikely to be able to break the pivots. Anyway, we're talking about being very gentle here. 

Refitting a pallet fork is not really difficult. Make sure that you have the fork the right way up. Using your tweezers, hold it by the arbor and seat the bottom pivot into the jewel hole. Try to get it as upright as possible, making sure that the pallet jewels are in the same plane as the teeth of the escape wheel. Next, carefully position the pallet bridge/cock over the fork and hover above it, trying to align the jewel over the upper pivot and aligning the screw hole and locating pins as well. Then lower it. Sometimes you'll get a "hole-in-one". If not, use a pegwood stick to apply gentle downwards pressure on the bridge/cock. Then using your fine oiler, gently nudge the fork till you feel the plate drop home. While maintaining pressure on the plate, get one of the screws in but only tighten it with the slightestamount of force. Get the second screw in a similar manner. Then test the fork by moving it left and right, then up and down. If everything feels right, tighten the screws a little more and test again. I everything is good then tighten it fully.

With good lighting and sufficient magnification, you should be able to refit a pallet in less than a minute. I recently became proficient in using a stereo microscope and I have to admit that it makes everything so much easier.

Maybe you could start practicing on pocket watches first, as the pivots of a pocket watch are more robust. Then advance to Russian watches, as their pivots are really strong.

Nobody gets it the first time. Practice until it becomes second nature. Good luck!

Special thanks to HectorLooi for pointing me in the right direction on where to get spare parts for ETA watch movements in Singapore. Although their website only mentions a few watch consumables, Khatena has many more watch parts (such as the 2824-2 pallet fork) that you have to call them to find out.

Edited July 5, 2021 by ifibrin

[ifibrin]

Update on pallet fork:

I bought an original ETA 2824-2 pallet fork, and I have managed to get the entire movement to function again! Turns out peg wood pressure is super critical to correct installation, and it’s a technique you have to really master.

However, that is not the main point of my update. I also bought some Chinese 2824-2 pallet forks which were claimed on the description by the seller to work with the original ETA 2824-2. However, the pivots are way too big to fit into the pallet fork jewels, and I thought it would be very helpful for others to know this. The tip of the pallet fork pivots do fit into the jewels, but most of the pivot cannot fit in. If you put the pallet bridge on, you would crack your pallet fork bridge jewels.

Notice that the lower pivot doesn’t fit properly into the jewel of the pallet bridge.

 

The Chinese pallet fork is above; it has larger pivots than the original eta 2824-2 pallet fork below.

 

The Chinese pallet fork pivot does not fit into the main plate jewel properly.

Edited July 14, 2021 by ifibrin

[ifibrin]

One other thing I realized is that the kind of loupe used has to be appropriate to the task. My Bergeon 15x loupe couldn’t show me clearly whether the pallet fork pivots were in, but the Bergeon aplanatic 10x (4902-1) allowed me to see clearly whether the pallet fork pivots were in. Even among other 10x eyeglasses I tried, the Bergeon 4902-1 was superior in field of vision and clarity, with no distortion.

[oldhippy]

In the end  I think it all depends on ones eyesight and the magnification and quality of the eyeglass.  

[Nibbler]

I have learned to use a stick and an old oiler to get the pallet fork in alignment. With 3x mag I can do it quite easily after a bunch of practice. I never push down on the bridge and usually just mess with the fork until the bridge drops into place.

mileage may vary,

Matt