Help with Seth Thomas A206-002 movement.

[Lloyd M]

After cleaning and oiling a rear wind Seth Thomas A206-002 movement, I have had problems getting it to run slow enough. It has a foating balance which appears to be working fine, but I have the adj all the way as slow as possible and it still gains about 10 min/hour. I tried a new Hermle balance unit, but the center height is not the same so it would not assemble.
What other items would make it gain??

 

[shutterbug]

There are several possibles, but if it's out of beat (uneven) it could cause the issue you describe. There may be easy fixes to the issue (assuming it IS in beat) but we'll need a picture of the top of the balance.

 

[Willie X]

Lloyd,

10 minutes in an hour would most likely indicate a serious problem with the escapement. How much amplitude do you have with the ballance movement? These little movements are farely robust, to be so small, and normally run with well over 360 degrees rotation.

With a sharp wood peg tap the fork gently against the double pins (roller table) that drives the balance. You should have adequate (but close) clearance between the fork and the double pins and hard banking against the banking stop, with the escapement pallet pin NOT bottoming in the gullet of the escape wheel.

A beat amplifier can help a lot to help locate some troubles. Performing the above test should result in a single noise, when the fork hits the banking stop. Stray noises can usually be tracked down easily and corrected.

Don't go of on a tangent and start to make weight changes on the balance rim, etc. Your problem is a basic flaw, probably in the escapement adjustments, or possably resulting from a lack of power to the escapement.

Good luck, Willie X

 

[Lloyd M]

Thanks for the tips. I will be getting back to that movement tomorrow. I have a beat amplifier, and noticed extra noises, but was not intent on them yet.
I will get a photo and check the other items also.

 

[al_taka]

Thanks for the tips. I will be getting back to that movement tomorrow. I have a beat amplifier, and noticed extra noises, but was not intent on them yet.
I will get a photo and check the other items also.

This is just a long shot guys but when a movement has not enough power reaching the escape wheel, doesn't it run fast?
If this is the case, power is being robbed somewhere before it gets to the escape wheel.

Does the clock stop long before the 8th day?

Al T.

 

[Lloyd M]

I have taken the photo of the top of the balance unit and attached.
As far as the rotation of the balance unit when running- it goes less than 90 degrees, but does so quickly.
Another item, I have to leave the cap off the rear end of the pallet pivot or it will drain the power, the pivot seems to stick though the rear plate to much. If I move the front cap, and put the rear cap on,it pivots fine.
The stray noises I am hearing I think are coming from the pallet pins as they lock on the escape wheel.

 

[Smudgy]

It sounds like you are having problems with the pallet fork. Anything that dampens the power transmission through the pallet fork on its way to the balance will cause the problems you've described. The balance should be turning a much larger arc than you describe. Check the pallet pivots, it sounds like that is the source of the problems. Also check the hole and cap jewel for the same pivots. The pivots should fit close with no appreciable slop, but with free movement. With the power off if you tip the movement to one side the pallet fork should fall to that side, tip to the other and it should tip to that side. If the fork doesn't fall to the low side during this test it means that the forks aren't as free as they need to be. It may be a bent or mushroomed pivot, or a problem with the jewelling. From your description it also sounds like the pallet arbor may be a bit long. That could be caused by the jewelling needing to be adjusted, the plates being bent, or a pallet staff that is too long and needs to be shortened (most likely the jewelling needs adjusted). In any case, the pallet staff pivots sounds to be at the center of the problems you've described.

While you have the balance off of the movement give it a spin. Make sure that it is free to run and doesn't dampen out too quickly. Sometimes this type of balance will have the suspension wire that it rides on develop grooves where the balance jewels ride. The grooving causes the balance extra friction, resulting in the balance motion being dampened. If the wire is grooved it will need to be replaced.

 

[Cactus50]

Before you start making changes in the escapement/balance assembly you need to determine where the fault lies, in the gear train or escapement. You can check by gently applying pressure to the minute hand (assist it in moving) if balance amplitude increases to normal, problem is in the gear train, if amplitude does not change, problem is in the escapement. Generally, if it was a good running movt. in the period before serviceing the escapement will be OK. Having said all of that, the most common fault I have found with these particular movements is pivot hole wear.

 

[Lloyd M]

Well, I removed and burnished the pallet fork pivots, I could see a dirty spot under 10X loupe. First time to do that with a loupe!!
Must have been part of the problem, cause now the caps do not retard the pallet fork. It falls free when tipped. Burnished the other gear pivots in the time train also.
Put it back together, oiled, but it still gains the same.
Could the spring on the balance wheel be weak??
Are they different strengths for the different movements??
Applying pressure to the minute hand adds a little amplitude, to a little over 90 degrees.
The owner said that it did not run, and it was dirty, but there is no signs of worn pivot holes.
I will keep watching it and see if anything else looks like it is stealing power.

 

[Willie X]

Lloyd,

Sounds like you have addressed at least some of the problem.

A good test to see if enough power is getting to the palet / fork assembly is to: take out the balance, make sure the clock is wound up about 90 %, slowly push the, now free to move, fork slowly left and right with the little pointed wood stick I mentioned earlier.

If power is adequate, you will get a nice little click, as the fork is impulsed to snap over to one side, and the pallet pin will be drawn tight to the escape wheel. A slow and careful nudge, with the wooden stick, in the other direction will cause a similar click and draw. The motion should be clearly positive, any slugishness means trouble in the train somewhere. Do this several times to make sure you are getting a good read.

A fast running 130 is almost certain to have escapement problems or loss of power problems. If the balance spring and wheel look OK, it probably is not the problem. This is one of those areas where eveyone wants to start working on the balance, but unless it has been visably damaged they will be barking up the wrong tree.

The above test should rule the loss of power issue either in or out. If power looks good, it's time to take a closer look at the escapement.

Another quick test for general condition of these clocks is to let the power all the way down and while looking down throught the plates, with magnafication, push the mainspring barrel sharply back and forth with your fingers. You should see the escape wheel jump back and forth a tiny amount in each direction, and there should not be any lateral movements of the shafts. In other words if you see a lot of wallering around in the pivot holes, time to overhaul or replace.

Good luck and hope this helps, Willie X









probablys are changeable but no longer in production for this clock

 

[Lloyd M]

Lloyd,

Sounds like you have addressed at least some of the problem.

A good test to see if enough power is getting to the palet / fork assembly is to: take out the balance, make sure the clock is wound up about 90 %, slowly push the, now free to move, fork slowly left and right with the little pointed wood stick I mentioned earlier.

If power is adequate, you will get a nice little click, as the fork is impulsed to snap over to one side, and the pallet pin will be drawn tight to the escape wheel. A slow and careful nudge, with the wooden stick, in the other direction will cause a similar click and draw. The motion should be clearly positive, any slugishness means trouble in the train somewhere. Do this several times to make sure you are getting a good read.

A fast running 130 is almost certain to have escapement problems or loss of power problems. If the balance spring and wheel look OK, it probably is not the problem. This is one of those areas where eveyone wants to start working on the balance, but unless it has been visably damaged they will be barking up the wrong tree.

The above test should rule the loss of power issue either in or out. If power looks good, it's time to take a closer look at the escapement.

Another quick test for general condition of these clocks is to let the power all the way down and while looking down throught the plates, with magnafication, push the mainspring barrel sharply back and forth with your fingers. You should see the escape wheel jump back and forth a tiny amount in each direction, and there should not be any lateral movements of the shafts. In other words if you see a lot of wallering around in the pivot holes, time to overhaul or replace.

Good luck and hope this helps, Willie X



Thanks Willie X for the hints,
I removed the balance unit and moved the mainspring barrel to look for worn pivots, but did not see any. I checked them for end shake at the same time to see if there were any binding there, but all looks good.
I applied one turn on the mainspring and could get the pallet fork to click over when moved with the wood. As I applied more spring tension the click over was firm,but seemed to go without any binding.
I oiled the balance jewels a tiny bit to see if that would help. The balance seems to run for a good amount of time when out of the movement and spun.
I have talked to Empire Clock to check on a replacement balance unit, and he suggested that I do a smoothing on the pivot holes as well as the cleaning to gain power. I will do that and see if it helps.





probablys are changeable but no longer in production for this clock

 

[Lloyd M]

Just a followup.
I think that I found the problem!!
I found that I had a new pallet fork in my inventory- and nothing to lose by trying it- so I installed it and the movement has been close to time now for half an hour, the amplitude of the balance is near 360 degrees and the BPH is close. I will leave it run tonite and see what morning brings.
Thanks for all the input, it kept me focused on the area that was the apparent problem.

 

[JAT]

Where did you get a spare pallet fork? I need one for a A206-002 movement. Thanks, JAT