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Replacing balance staff on a Waltham 1015 model 1900

bll30148

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Nov 4, 2020
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Hello - I have a Waltham 1015 model 1900 size 0s 15j with serial number 10174273. The balance staff is broken and needs replacing. Two questions:

1) Where can I find the part number for a new balance staff?

2) How can I determine if it is friction-fit or riveted?

Thanks in advance.

-Ben
 

Jerry Treiman

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In spite of the special casing, the movement takes all the same parts as a standard 1900 model. It will be a friction staff and you should see the typical blued steel hub that must remain in the balance wheel. According to my material catalog it will need one of two different staffs: #20207 (straight shoulder) or #20208 (taper shoulder). You will have to determine which one it is based on examination. The roller table for the 20207 has a larger hole than the one for the 20208 and the attached illustrations, although for 16-size models, show the basic shape and fitting differences. You will need a special stump in your staking set to support the hub while you drive out the friction staff.
>> straight shoulder staff on orange background, taper shoulder staff on gray <<
4860.jpg 4861.jpg
 

bll30148

New Member
Nov 4, 2020
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In spite of the special casing, the movement takes all the same parts as a standard 1900 model. It will be a friction staff and you should see the typical blued steel hub that must remain in the balance wheel. According to my material catalog it will need one of two different staffs: #20207 (straight shoulder) or #20208 (taper shoulder). You will have to determine which one it is based on examination. The roller table for the 20207 has a larger hole than the one for the 20208 and the attached illustrations, although for 16-size models, show the basic shape and fitting differences. You will need a special stump in your staking set to support the hub while you drive out the friction staff.
>> straight shoulder staff on orange background, taper shoulder staff on gray <<
View attachment 623911 View attachment 623912
Thank you, Jerry.
Judging by the attached picture, would you say it looks like the #20207 straight shoulder (orange background)?
Also, by special stump I am guessing you mean a stump with a beveled hole, right?
Thanks in advance.
-Ben

IMG_3363.jpg
 

Jerry Treiman

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Yes, that does appear to be the straight shoulder staff (20207) and the special stump will have a beveled hole to support only the blued hub. Alternatively you can use a hole in the table of the staking tool that will clear the shoulder (F in the drawing) but support the hub (C).
Here is the page of instructions from the same booklet that the drawing came from.
H04.jpg
 

Andy Dervan

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Ben,

If the problem is just a broken pivot; Mahlon Shetler will repivot it for you. He does watch repivoting routinely....

Mahlon Shetler
3345 Highup Road
Jasper, NY 14855

Andy Dervan
 

Andy Dervan

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I provided his address see above. He is an Amish watch repairer and does not have a telephone.

He does 1500+ watch repivots a year. I watched do several and was amazed by his process so we wrote for NAWCC Watch and Clock Bulletin about it.

Andy Dervan
 
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