Waltham roller table

[ghtaggart]

Hello,
I’m restoring a Waltham 18s, PS Bartlett model, type 1883. Replacing the staff I’ve discovered from Fried’s repair manual the position of the roller table may be different on certain models not being positioned at the 90 degrees from the balance arms. Not having this knowledge for this movement when disassembled, is there a source for this available?
Thank you in advance.
V/R
Henry

 

[Jim Haney]

Henry,


No, there is no book that tells you where to locate the roller table.

Most repairers just mark where the old table w/jewel is located and put it back in the same location.

If it was missing and could not be marked you can stake it at 90o and then place the jewel in the fork and turn until the pallet fork is in the middle of the banking pins and then note or mark where the HS stud would be at ( with the BB on) so when put it back on the stud will be in the spot you marked...

 

[Appa69]

100% what Jim said.

 

[Skutt50]

As Jim said above, most watchmakers make some kind of mark. If you are lucky you will find a small scratch or even a small file mark showing the direction of the roller jewel. I find this on close to half of the balances I replace the balance arbor on. Look closely, usually on the bottom side of the wheel. The marking may be quite small and hard to identify.........

The advantage of doing so is that the poise of the balance stays more or less untouched. If you missed the positioning when disassembling the balance, the watch will run if you follow Jims suggestion above but you might have to do a dynamic poising, if you want it to perform perfect in various positions.

 

[ghtaggart]

Excellent! Thank you both for this valuable information!
Henry

 

[ghtaggart]

I understand completely and have put into practice the 90 degree rule for roller jewel positioning. Found it best especially after RT removal and restate to check for balance poise.
The question I’m still left with comes from Henry Fried’s manual stating in the section single roller table positioning to use the 90 degree rule but, there are certain exceptions for certain specific models.
I’ll attempt to post an image of a verified balance from a 1883 Waltham that causes confusion.

 

[ghtaggart]

Attempted to post pictures.

 

[Skutt50]

Here is my guess on the subject:

In a "standard" design of the escapement the roller jewel will be positioned at a 90 degree angle trom the balance wheel sprockets. When the hairspring is attached and the watch is in beat, the hairspring stud will rest straight above the balance wheel sprocket. The design means that the hairspring stud mount is also at a 90 degrees angle from a straight line between the pallet fork lever arbor and the balance arbor.

In some movements (because of the design) the hairspring stud is NOT fastened at a 90 degree angle This means that there will not be 90 degrees between the roller jewel and the stud. So you have to decide which part you want to move. The roller jewel or the hairspring stud.

This deviation is in my experience not that common but I have come across it on several occations. I don't remember which movements but I have seen it on both wrist watches and pocket watches.

 

[ghtaggart]

Thank you for that Skutt.

I also wonder could the hairspring by design be a factor. The model Waltham 1883 I’m working on has the light brequet over coil type. Anchor point in a very peculiar spot compared to most.

 

[Skutt50]

I also wonder could the hairspring by design be a factor.

Not quite sure what you mean but,

The hairspring is matched with the balance wheel to give the correct frequency for the movement. When doing so the hairspring is measured to length and when the oscillation frequency is correct the hairspring is cut, (leaving enough for fastening etc).

Then about the overcoil design. There are tables available with various hairsprig shapes that is used for the curvature of the overcoil. It depends on where the overcoil starts and ends and which position is most critical for timekeeping e.g. Pendant Up for a pocket watch. (Think of the hairspring held over a dial - e.g. 3 and 6 o'clock.) I have a book with several pages full of drawings but I can't remember the name right now, (I am not close to my workshop) but I am sure you will get suggestions by other members.......

 

[gmorse]

Hi Skutt,

I have a book with several pages full of drawings but I can't remember the name right now, (I am not close to my workshop) but I am sure you will get suggestions by other members.......

Donald de Carle's 'Practical Watch Adjusting' has tables of these curves in chapter 5.

Regards,

Graham

 

[Skutt50]

Thanks Graham, that is the book I was thinking of. I was just not sure about the name and author....

 

[ghtaggart]

Thank you for that valuable resource gmorse. I’ll definitely search for a copy.
Henry