Help with a 992B

[rrwatch4me]

I have a 992B that I just cleaned and lubed a few days ago and it will not start up on its own, even when fully wound, unless I give it a little shake. Does it sound like I over-lubricated it? Weak mainspring? Im really not sure how it behaved before I cleaned it. I bought it, saw that it was filthy but running, and immediately took it apart for cleaning. Thanks

 

[doug sinclair]

Please describe fully the steps you used in servicing the watch, including solutions used, cleaning machines, etc. etc. What is your prior experience in repairing watches? Is the hairspring true, centred, flat, and not rubbing anywhere? Did you use pegwood on the jewels, and pith wood on the pivots and pinions? It's difficult to trouble shoot over the 'net considering all the things that could be wrong.

 

[rrwatch4me]

Sure. I have pretty limited experience with repair. I have collected for about 25 years and and I clean and lube my watches by hand (no machine) using L&R ammoniated cleaner and rinse solutions, brushes, pith and pegwood. I usually have no problems. The hairspring is perfectly flat and not rubbing anywhere that I can see. No cracked jewels. Pivots look good. It seems to be in beat and timing is within 5 seconds per day. Its running well just not starting on its own. I use Mobius 8000 oil. I always remove the mainspring, inspect, clean, lubricate and re-install if it appears OK. Hope this helps.

 

[topspy]

Try this: Let the power down completely and remove the balance and pallet fork. A single 'click' or two of winding should set the escape wheel spinning, if not look at the train. Remove the hairspring from the balance and pin to the balance cock to make sure the collet is centered over the jewel, correct if not. Replace on balance in original position and install without the pallet fork. Insure roller jewel sits between the banking pins on a line between the escape wheel pivot and balance pivot. Install the pallet fork and wind a bit. Oil 2-3 teeth on the escape wheel. Check that pallet 'snaps' from one side to the other with a nudge. If it won't start after that inspect balance and fork pivots, endshake.

 

[doug sinclair]

Again, it is difficult to troubleshoot at arm's length. You might have an off beat problem. Have you checked that? With the watch totally run down, the pallet arm should be dead centre between the banking pins. If it isn't, you'll need to turn the hairspring collet in the right direction, the right amount, in order to set the beat correctly. You asked if you "over lubricated it"! The pivots on the pallet arbor require minimal to no oil. If you over lubed there, particularly the top pivot, that might contribute to your problem. How could we know for certain? Describe how you lube your watches. You use L & R cleaning solutions and rinse. Specifically WHICH L & R cleaners and rinses? Weak mainspring? With the watch totally run down, if all else is correct with the watch, it should self start after five or six turns of the crown. So the mainspring is not your problem!

 

[rrwatch4me]

Ok Thanks. I now get to replace the staff due to a slip of the screwdriver while removing the hairspring stud. First one Ive ever broke. Oh well. Not a huge deal. The train does start easily with the pallet and balance removed so, I'm beginning to think that the hairspring collet is slightly off. Since I have to remove the HS for the staff replacement, I'll make sure it is re-installed correctly and go from them. Thanks!
PS: Doug, I use L&R #111 Ultrasonic cleaner and #3 Rinse. I use a basic small oiler and cup. I dip the oiler in the cup and just touch each pivot hole.

 

[Paul_S]

This is a typical sign on an out of beat watch. You note the watch seems in beat, but I would evaluate that before looking for more obscure causes.

 

[tkarter]

I would have cleaned the hairspring first.

 

[Rob P.]

Non self starting in something like a 992B is either a beat problem or you oiled the lever pivot jewels.

The watch needs to be slightly out of beat to self start because if it were perfectly in beat, the lever would be in the center when fully wound down. That provides no or insufficient impetus to the balance to allow the movement to self start when wound. Remember, the lever has to impulse the roller to get the balance to move. If the lever were perfectly centered when the power came on, it wouldn't move and couldn't impulse the roller.

Lubing the lever pivot jewels slows the action. This robs the escapement of enough power/energy to prevent self starting. Not enough power and there isn't enough energy to move the balance enough to start it oscillating.

 

[topspy]

If the lever were perfectly centered when the power came on, it wouldn't move and couldn't impulse the roller.

If the lever is centered, winding the watch would cause the palette to draw, therefore impulsing the balance. Isn't that why a watch has to be in beat to self start?

 

[doug sinclair]

A watch well adjusted and in excellent condition should start by itself after a few winds. Once an escape wheel tooth has locked on a locking surface of the pallet stone, the geometry of the escapement is such that the pallet should be drawn to the banking pin which causes the balance wheel to turn slightly. There should be a natural tendency for the balance wheel to pull back against the draw of the pallet to cause the pallet to unlock, thereby causing the watch to commence running again. I retrieved my Hamilton 952 from the safe. It runs within 20 seconds a month, and it is a watch that I serviced most recently. It was totally run down, and the balance wheel motionless. I commenced winding the watch, purposely not disturbing the balance wheel. On the 11th turn of the crown, the watch commenced running. I rest my case!

 

[rrwatch4me]

Well, whatever it was is now fixed after I replaced the balance staff today. Its running better than ever and started up on about the 5th wind. Thanks for all of the help!

 

[Rob P.]

If the lever is centered, winding the watch would cause the palette to draw, therefore impulsing the balance. Isn't that why a watch has to be in beat to self start?

Well, from what I understand, a watch set "perfectly" centered in beat will be at that precise moment between impulse and draw. It can't draw and it can't impulse because to do one or the other means that it must fight against the opposing force. Which are equal.

For a watch to self start it must be slightly out of beat. Emphasis on "slightly". That allows the EW to move, drop, & impulse the pallet/lever/balance, and the watch self starts. Or it must be so overpowered that the power necessary to impulse the lever is greater than the draw/friction.

This is what I understand is going on in there. I may be wrong but it is what I understand about how things work. However, in the real world, side shake, tolerances, and human error all compound to allow a watch which is set perfectly in beat to self start.

 

[doug sinclair]

A watch well adjusted and in excellent condition should start by itself after a few winds. Once an escape wheel tooth has locked on a locking surface of the pallet stone, the geometry of the escapement is such that the pallet should be drawn to the banking pin which causes the balance wheel to turn slightly. There should be a natural tendency for the balance wheel to pull back against the draw of the pallet to cause the pallet to unlock, thereby causing the watch to commence running again. I retrieved my Hamilton 952 from the safe. It runs within 20 seconds a month, and it is a watch that I serviced most recently. It was totally run down, and the balance wheel motionless. I commenced winding the watch, purposely not disturbing the balance wheel. On the 11th turn of the crown, the watch commenced running. I rest my case!

Rob P.,

Please re-read the above. Certainly, not every watch would react as this 952 did, but a quality watch, in beat, well adjusted, and in good condition certainly should. My Vibrograph indicates that this watch is perfectly in beat. That means that either pallet would be in a position to lock an advancing escape wheel tooth as you imply. But taking draw once lock has occurred into account, the watch should start like the 952 did.

Oh! By the way, this watch has the correct mainspring in it.

 

[rrwatch4me]

Non self starting in something like a 992B is either a beat problem or you oiled the lever pivot jewels.

The watch needs to be slightly out of beat to self start because if it were perfectly in beat, the lever would be in the center when fully wound down. That provides no or insufficient impetus to the balance to allow the movement to self start when wound. Remember, the lever has to impulse the roller to get the balance to move. If the lever were perfectly centered when the power came on, it wouldn't move and couldn't impulse the roller.

Lubing the lever pivot jewels slows the action. This robs the escapement of enough power/energy to prevent self starting. Not enough power and there isn't enough energy to move the balance enough to start it oscillating.

Are you saying that the pallet fork pivot jewels should never be oiled? I've always oiled them the same as all of the other jewels.

 

[topspy]

Generally from what I understand, wrist watch pallet fork pivots should not be oiled. With pocket watches it's a bit grey, but if they are jeweled I don't oil..... The way I see it is that since by the nature of reducing torque as you progress down the train, by the time you get to the pallet drag from surface tension with the oil offsets any lubrication advantage. Also the fact that the pallet does not rotate 360 degrees means that oil hardening applies to one side of the pivot, complicating matters.

 

[topspy]

Well, from what I understand, a watch set "perfectly" centered in beat will be at that precise moment between impulse and draw. It can't draw and it can't impulse because to do one or the other means that it must fight against the opposing force. Which are equal.

For a watch to self start it must be slightly out of beat. Emphasis on "slightly". That allows the EW to move, drop, & impulse the pallet/lever/balance, and the watch self starts. Or it must be so overpowered that the power necessary to impulse the lever is greater than the draw/friction.

This is what I understand is going on in there. I may be wrong but it is what I understand about how things work. However, in the real world, side shake, tolerances, and human error all compound to allow a watch which is set perfectly in beat to self start.

If this was true, watches would not run at all! The power of the mainspring must exceed the force of the hairspring - they do not 'balance out.'

 

[Smudgy]

If you oil the pallet fork pivots you will lose 1/8 to 1/4 turns on the balance.

A watch perfectly in beat will start easier than one "slightly" out. A watch that is out of beat to any great degree will not reliably self-start. A lot of people on the clock board think that you have to set the balance slightly out of beat to have it self-start, but they don't often work on the lever type escapements and don't seem to fully understand it. If you believe that being slightly out of beat is required for a lever escapement to self-start you need to disabuse yourself of the idea.

 

[Bohemian Bill]

I have to agree with Doug..I have observed watching my watches. If the watch is wound completely down (check by release the click) and perfectly in beat and the pallet fork is centered between the banking pins and the pallet jewel resting on the escape tooth. When the train get enough power to move the escape wheel & hairspring tension to lock the escape tooth. At that point the balance will receive a half or weak impulse to start the balance moving. As you add winding power the impulse will gain more impulse power to finally attain full balance wheel amplitude.

 

[doug sinclair]

I have done this kind of work for 60 years. I was taught by my mentor (my late father) to leave pallet arbor jewels dry. Some folks moisten sharpened pegwood, dip the tip in oil, and insert the tip into the jewel. Some folks oil the jewels. I doubt there is any real harm in oiling the arbor jewels. Just make absolutely certain that an absolute minimum of oil is used on the top jewel. You do not want a bleb of oil to form between the pallet cock and the lever. Viscous friction can reduce the impulse given to the balance by the pallet. Admission! If I run into a watch in which the pallet arbor is an extremely loose fit in the arbor jewels, resulting in a "twitchy" lever which wants to "flutter", I do oil the arbor jewels.