I'm a new kid on the block here so I apologize if this has been already discussed and I could not find it. Anyway this is a stumper (for me).
I have been working on PW's for about a year now. Mostly cleaning and learning. This BWR is one of the first watches I bought but took me some time to get up the nerve to work on it. Finally I cleaned and oiled it (it was working when I got it but I didn't test it.) I got it all cleaned and oiled and it ran like a champ. It ran so well and regulated up to keep perfect time. It became my favorite and I wore it every day for about 3 months, maybe longer. Then all of a sudden for no apparent reason it just stopped. If I gave it a little shake it would start up and run for a while and then stop. I finally decided I must have done something wrong in the cleaning process so I cleaned it again. Also during the 3 months I aquired a 30X microscope so when I cleaned it again I inspected all the jewels and all the pivots and everthing looked fine. I even pulled the balance jewels and took extra care to clean them thoroughly. I put it back together and got it started back up and it ran strong...for about 5 hours and then stopped; give it a shake and it starts right up and runs for a while and stops. I do notice when it stops I can take a piece of peg wood and gentley try to turn the balance and the balance is truly bound-up. A little push and it again runs freely for a time. I checked the roller jewel and the pallet under the microscope and saw nothing suspicious. I did notice a small crack in the center of the cutout of the double roller but nothing looks out of shape. As near as I can see down under balance nothing is interfering. And the hairspring look fine. Sorry for all these words but I'm stumped. Do you experts have any ideas??? I appreciate any input. Cheers,

You ran it for three months... hrm. I would usually guess a barrel problem. If it's running for five hours and then stopping it's losing power, obviously. What happens every five hours (or so). Look for some round rubbing on the plates. Probably something else but I can't think of it right now... oh, look at the gearing on the minute wheel and hour wheel, check the pinion. You might be missing something obvious regarding the casing, dial and hands. If you strip it back down to just the movement and wind it up how long does it run? You can make a little dot on the hour wheel so you can get a rough idea of how long it ran if it stops. Hope that helps a little bit. Intermittent running can be the hardest to figure out.

Did you replace the mainspring? Could be that the mainspring brace is too long and sticking up out of the barrel and catching on something. Or the barrel cap isn't seated and that could be rubbing on the balancewhen it comes around. Just a few thoughts. Let us know what you find.

Hi Ronald,

The fact that your BWR ran for 3 months before acting up is significant, provided it hasn't received a serious enough jolt that could have chipped a jewel shoulder or done other damage. Since you didn't mention any 'incident' preceding the initial stoppage, I assume there wasn't any such event. So maybe we can rule out additional, unwanted friction caused by damage.

I agree with both Frank and Lawrence about rechecking everything to make certain there is no interference/rubbing anywhere. I am curious, however, about the other significant thing you mention when you state that the balance appears "bound-up" when it stops. Now we have to be suspicious of something either escapement related, or more specifically fork/roller relationship. Is the double roller a 2 piece roller? I am now drawn to the fact that you see a "small crack in the center of the cutout of the double roller". If you are referring to seeing a crack in the passing hollow of the safety roller, and if it's a 2 piece roller, then this makes me suspicious that the safety roller is slipping on the staff. If it's truly a crack, then it likely no longer has enough friction to keep it from turning on the staff. And, if it 'is' turning/slipping it will cause you all sorts of grief with binding, stoppage, etc.

Gene

Ronald,
If your mainspring is an old steel one, replace it with a new white alloy one.
Brian C.

Suprised no one mentioned a loose roller jewel. Sometimes they are not so obvious at first glance but try moving it with pegwood stick. For what it's worth.
John

Thanks, to everybody for all your sage input!

Please test my logic here. I checked and rechecked for places that could rub. Nothing found. I didn't challenge the mainspring because when it is out of the barrel, it expands greatly and doesn't show what I would interpret to be "set". And when the watch was running, I never timed it but it had to be better than 30 hours. On thing I failed to mention earlier is the stoppage does not occur on any regular interval. It sometimes runs for two or three hours and sometime only for a few minutes. Also it now seems like the problem is progressively worsening. Which leads us to the balance/escapement. I did not realize that there were two piece double rollers. I will pull the balance again and look at that much more closely and check for looseness. And while I did look at the roller jewel under the microscope for damage, and it looked OK. I did not check it for looseness. I will do! These seem to me to be the most likely issues since I am sure the balance binds when the stoppage occurs. I do not see how mainspring issues would cause the balance to bind. If I'm wrong please let me know. So I will now dig in to the balance issues and see what we find.
Thanks again to everyone for the great response. I will let you know what happens.
Cheers, RM

Ron, As the BWR in 18s was made as a model 7 and a model 8 (exposed winding wheels), and as I don't know which one you are referring to, I noted below (with arrows to help) my own experiences with stoppage.
Model 7 (left side) the Barrel cover rubs ever so slightly on the bottom of the Balance wheel. You have to tighten the barrel cover or adjust the height of the balance wheel.
The Model 8 (right image) balance wheel can begin rubbing on the inside of the cock where the balance weights will rub and stop the watch. Also the wheel itself if it is slightly "wobbly" can (and will) stop itself on the Pallet fork bridge under the wheel. As yours is a double roller, I expect this is where you should be looking.
In BOTH cases if the balance (hair) spring get a little out of alignment it WILL rub on things and slow or stop the wheel.
Finally, if the roller is cracking or splitting, it can/will loosen up causing the roller pin to get jammed. I don't think so "yet" as you say it starts running again, and that would be unlikely as a defective roller would STOP it.

Thanks David, for the new input and the prompt, I was just getting ready to post a progress report. My inexperience is showing as I didn't know about the model 7 or I would (hopefully) have mentioned it. Mine is the model 8, it looks exactly like your photo on the right.
Well, I did go back and double check both the roller and the roller jewel for tightness and alignment. They check-out fine. After that I started thinking about what everybody said about the mainspring. I know nothing about the mainspring itself. I have heard people say you should change the mainspring every time you clean a watch. So I decided to order a new mainspring and Brian C. helped me with that. It just arrived so I am making plans to get after that this weekend. We'll see how it goes. There may still be an interference issue to find but at least I will know maximum energy it getting to the escape wheel.
Since I have to share time between watch work and everything else my progress is slow but I will post the results at the next step. Thanks y'all!

Ron and everyone else.
It's better to go slow than to rush.
Well, maybe it's better for me, selling parts, if you rush.
Brian C.

I got it working!!!!! My favorite 18s is back in my pocket! Sorry, let me back up and fill in the blanks. A while back I was getting ready to install a new mainspring and had a good rational on why that could be the problem. Indeed, I did install the new mainspring and that really did perk the watch up. But son-of-a-gun it stopped just as surely with the new mainspring as with the old. After my head stopped spinning around, I decided to observe its behavior and see if I could decribe it. (Wonder why I didn't do that before.) Suddenly I discovered that in the dial down position it did not stop but in the dial up position it would stop fairly consistantly with 5-10 minutes. Thanks to the good input from y'all, I began focusing on the balance cock jewel and pivot. Well, when I disassembled the jewel to clean it, somehow I didn't notice that it has two different sized screws holding the cap jewel. Evidentally when I reassembled the jewel, I reversed the two screws. In my delerium or whatever it was I didn't notice that one screw tightened up real tight and the other just spun around like it was stripped. I was even somewhat surprised when I reversed them back that they both tighted up just fine. Well, if you can imagine, after I did that the watch started running like a champ! Today is the sixth day it has run fine and keeping good time in my pocket. Apparently even with the close tolerances of the balance jewels if the cap jewel is torqued only on one side the jewel will tip enough to cause the pivot to jam. Live and learn!
Thanks to all the great input from everybody. Now on to the next one...