Waltham 16s questions

[PeteFr2]

I am in the process of restoring a Waltham 16s pocket watch and the process has raised some interesting questions to which I can't find answers in any of my text books.

1. The watch had had all of the timing screws from the wheel removed and although the screws were present I had to search for images of other similar watches and guess their position. I think I have succeeded and have managed to dynamic balance my first wheel and the rate now seems good. However, my question is, why are the screws grouped and positioned in the specific pattern and why not equidistant. Is there a method of finding the 'factory' positioning? Furthermore I have read that it is advisable when removing a roller table or wheel from the staff that the relationship in position relative to them both is important, I'm not sure why this is.

2. Considering the action of the roller jewel in the fork, surely it is basically a rolling action transmitting all the power of the impulse to the table - why no lube? (everything I've read advises against it)

 

Sorry, I am only asking questions at the moment, I haven't yet got the experience to offer any advice but if I live long enough I'm sure eventually I'll be able to help others. Hoping that someone with more experience than me will take the time to advise me.   Thanks.

[JohnR725]

Usually the number one thing we ask new people would be pictures give us a picture it may seem a really common for you but it be nice if for all on the same page with a picture.

Okay I'm a little confused you had the balance wheel in one box the timing screws in another?

If were talking about a bimetallic balance wheel or any balance wheel for that issue it has to be? It has to be absolutely perfectly poised in all positions. If you take the roller table off and put it in some other position to upset the poise. Before you can even think of poising and this is statically first not dynamic the balance wheel also has to be round. This is because bimetallic balance wheels a lot of times we get squeeze the arms will move in and out so they have to be in very exacting positions.

Then the screws they come in matched pairs at least there supposed to be matched. One screw on one side it's matched pair on the other side. If you start randomly positioning the screws your poise will be wrong.

On a bimetallic balance wheel it's unlikely if they been removed that you ever get them where there supposed to be. A bimetallic balance wheel its purpose is to adjust the arms based on temperature to compensate for the steel hairspring. In the early days it be adjusted from an ice box to something much warmer the screws would be in very exacting locations to cancel out temperature variation. Not saying a be impossible but if you rearrange the screws you going to lose the temperature compensation and getting down exactly back right is going to be quite challenging if basically not impossible.

As far as lubricating the roller jewel it's not needed would be the simplistic answer. There is really almost very little contact there very little rubbing contact it's not considered a high friction point.

 

 

[PeteFr2]

Thank you for your reply. Sorry about the lack of photos, I'm not very good with the technology yet. In any case it didn't occur to me relating to my particular query - I've taken some photos though and will attempt to add them.

Yes, when I got the watch all the timing screws had been removed and were in a glass vial so I had to guess their position. There were 4 mean time screws (north - south and east - west, as it were). These were easy to locate but for the others I had to look at images of other watches and try to guess the pattern.  I was wondering if there was a standard pattern from when the watch was made.

I understand how a compensated balance works and digesting what you've said it seems like the actual pattern they are fixed in is also a method of controlling the rate of expansion and contraction of the wheel and not just involved in poise. This sounds like a procedure for which I just don't have the equipment or knowledge. However, I did manage it and the watch is now running acceptably. I did a static balance first to get it in the ball park and ultimately dynamic balanced the movement to 8 positions plus DU DD (I got bored when I got within about 30 s per day).

As for lubrication of the roller jewel your comments are appreciated, I suppose the back side of the jewels being curved means that the surface area in contact is minimal and after all the pin is a jewel with a very low coefficient of friction. I wonder whether if lubrication might be of some use if the pin is steel?

I made my own static balancing tool which might be of interest as it is cheap to make and with extreme care it seems to work well for what the procedure is worth. When I started to dynamic balance I learned how far out it was once it was fitted to the movement with the spring and collet fitted.

[PeteFr2]

[PeteFr2]

[PeteFr2]

[KarlvonKoln]

Lovely Waltham that is!  So then, seeing if I'm understanding you rightly, you took a glass vial full of balance screws and put them back into a balance wheel, and managed to poise it well enough to squeeze +/- 30 seconds per day out of the movement?  Upon a poising tool which you built?  That's not too shabby at all.  I'd cringe at having to reassemble a balance like that, I admit.  It had to have been slow going.  To get it poised and trued and functional, that's good work.

[PeteFr2]

Thanks.  It did take me a few months and my wife quite often had to remind me to leave the workshop to eat & sleep.

[Nucejoe]

23 hours ago, PeteFr2 said:

As for lubrication of the roller jewel your comments are appreciated, I suppose the back side of the jewels being curved means that the surface area in contact is minimal and after all the pin is a jewel with a very low coefficient of friction. I wonder whether if lubrication might be of some use if the pin is steel?

  A watch may run if pins and escape wheel are like new, however, due to wear( which you might not see under normal magnification) lubrication and epilame treatment is a must. 

You are right,  jeweled ones can run without oiling but amplitude wont be impressive.

[Klassiker]

Like the OP, everything I've read advises against oiling, so I never do. I'd be interested to read references which recommend oiling, and arguments for and against. My guess is (and it is a guess, because I haven't compared with / without) is that the contact phase is a small sliding action under very low pressure with a little bit of rolling (so hardly any friction to be reduced) followed by a sudden separation of the surfaces in a more-or-less perpendicular direction. Even oils with a low viscosity will cause some drag in this case, due to surface tension, like when you pull an oiler out of the oil pot quickly. My guess is that oiling does not significantly reduce wear, but has a significant amplitude penalty.

If I do a test, I will let you know.

[Nucejoe]

On 4/12/2021 at 2:26 PM, PeteFr2 said:

 I wonder whether if lubrication might be of some use if the pin is steel?

 

Whichever, pallets or impulse pin, if metal, they should be oiled, metal against metal anywhere needs oiling and to ensure that oil stays put, you should treat it with epilame.

  I didn't use to oil jeweled impulse pin, if not mistaken I red an advice by Nickelsilver to use a bit of oil, I presumed it has more to do with the fork being metal.

Regs

Joe