Jump to content

Acquisition of Jewels/OD/Hole Diameter, Etc.

SparkyLB

By SparkyLB
in Watch Repairs Help & Advice

 Share

Recommended Posts

SparkyLB WRT Addict

SparkyLB

Posted
Posted (edited)

I can measure the OD of a jewel if out of the mainplate with a JKA Feintaster, or appropriate micrometer.  I'm fairly sure there is a tool (is it called a pin gauge?) to measure the pivot hole size.   

What I can't seem to find info about is, what if need a certain size jewel (outside diameter) with a certain size hole?  Below are two educated guesses:  Am I on the right track?

1.  I'm thinking jewels are acquired that are a bit large and the mainplate is broached to an appropriate size for the jewel to be pressed and depthed?  (speaking of friction-fit; I'm aware that there are jewels contained in bushings that shoulder to mainplate--but I'm not referring to those.)

2.  As far as the pivot holes, I'm guessing that this is something that is not changed (unless using a lathe and micro drill bits?) and one sorts through many jewels until an appropriate size is found, then back to step one?

Finally, are jewels purchased in lots on eBay, or are they purchased by caliber/movement number?  I've looked on eBay for weeks.  There's no shortage of pallet entry and exit stones, but there is a distinct lack of round jewels for wheels.

Thank you all.  Forgive me if some terminology is incorrect.  I'm still somewhat a beginner.  

Edited by SparkyLB
brevity is the soul of wit.
Link to comment
Share on other sites
watchweasol Distinguished Member

watchweasol

Posted
Posted

Hi   Regarding jewels they come in a lot of different sizes and as far as I am aware three types of setting, some are friction fitted using a seitz jeweling tool, some are in a brass setting and are screwed in and some are rubbed in. The rubbed in variety require special tools to remove broken or chipped jewels and a tool for rubbing in the new jewel into its setting.

There are assortments of jewels on ebay but it means sorting through and trying each one to find the correct fit, If you know the calibre and make and find the part number for the jewel then you are sure you get the correct size. The thing to do is to measure the pivot requiring the jewel then either order the same. Or if you are lucky enough to have phials of calibrated jewels select the correct size 

  • Like 1
Link to comment
Share on other sites
Alaskamick WRT Addict

Alaskamick

Posted
Posted

You could buy drill bits from Cousins, they go from 0.5m to 2.00 mm.

These are jewellery drills but there are all types available, you would need to gently feed the drill through until you get to the shank witch will be the size of the hole.

Never having looked for jewels I'm not sure what the hole size would be.

  • Like 1
Link to comment
Share on other sites
vinn3 Distinguished Member

vinn3

Posted
Posted
2 hours ago, Alaskamick said:

You could buy drill bits from Cousins, they go from 0.5m to 2.00 mm.

These are jewellery drills but there are all types available, you would need to gently feed the drill through until you get to the shank witch will be the size of the hole.

Never having looked for jewels I'm not sure what the hole size would be.

    twist  drills shanks can be sliped into the hole for an aproximate I. D..    vin

Link to comment
Share on other sites
SparkyLB WRT Addict

SparkyLB

Posted
  • Author
Posted
3 hours ago, vinn3 said:

 

     the best tool for measuring a hole is a "ball micrometer".    you could make one via lathe.    i don't think one that small can be found.   vin

Thank you, vin.  I'll have a look at these implements.  I think I've seen spring loaded pin-type tools with a display not unlike a thermometer, and depending upon how deep the tapered pin enters the hole, the graduations on the stationary part tell the diameter.  

3 hours ago, watchweasol said:

Hi   Regarding jewels they come in a lot of different sizes and as far as I am aware three types of setting, some are friction fitted using a seitz jeweling tool, some are in a brass setting and are screwed in and some are rubbed in. The rubbed in variety require special tools to remove broken or chipped jewels and a tool for rubbing in the new jewel into its setting.

There are assortments of jewels on ebay but it means sorting through and trying each one to find the correct fit, If you know the calibre and make and find the part number for the jewel then you are sure you get the correct size. The thing to do is to measure the pivot requiring the jewel then either order the same. Or if you are lucky enough to have phials of calibrated jewels select the correct size 

Thank you, watchweasol.  You answered the question regarding can jewels be ordered by part number, i.e. calibre.   

3 hours ago, Alaskamick said:

You could buy drill bits from Cousins, they go from 0.5m to 2.00 mm.

These are jewellery drills but there are all types available, you would need to gently feed the drill through until you get to the shank witch will be the size of the hole.

Never having looked for jewels I'm not sure what the hole size would be.

Thank you for the resource, Alaskamick.  I'll get some of these for sure.  I'm guessing they ain't cheap!

11 minutes ago, vinn3 said:

    twist  drills shanks can be sliped into the hole for an aproximate I. D..    vin

Absolutely.  

 

Thank you all for replying.  I'm putting back together a very old orphaned movement, and the jewel hole for the 3rd wheel (not a seconds wheel in this case) is badly broken, preventing the train of wheels to be driven; at least downstream of the center wheel.  

Link to comment
Share on other sites
 Share
Go to topic listing


  • Recently Browsing

    • No registered users viewing this page.

  • Topics

  • Posts

    • RichardHarris123
      Without Our Forum

      By RichardHarris123 · Posted

      No John, we don't want Mark to change anything, we are just scared of losing a brilliant forum and losing contact with each other.  As pointed out, this forum is full of knowledge and I for one,  consider the regulars friends. I would hate to lose contact with you and the others.   PS, this forum is really important to me. 
    • JohnR725
      Epilame / Fixodrop

      By JohnR725 · Posted

      one little minor problem with your chemistry experiment here which is what exactly is epilam? In other words is it an exact substance with the chemical you specify or is it a term? For instance originally it was steric acid either dissolved in some sort of solvent or it was applied by vaporizing it. Then now it's all kinds of different things the watch companies all have different ideas there's a whole bunch of patents. So is not always an exact substance.   let me snip out a image from the patent that I attached up above. Notice I highlighted something it seems to disagree with your evaluation.  
    • nevenbekriev
      Pocket watch escape wh

      By nevenbekriev · Posted

      I guess You had to try, as it would be hard to sleep without that try, but, I know the result before the experiment... As I told before, the friction will be so big that the wheel will not turn. The pivots have to be thin and polished - the bigger the number of the wheel (2th, 3gh, 4th...), the thinner the pivot. What You are trying to do is possible, but forming the new thin pivot must be done on lathe. Thus the wheel will get shorter, but can have new pivot without the drilling for normal standard repivoting. Then piece of brass can be soldered under the pivot hole in the bridge and new hole drilled in it to form the new bearing.  Well, this way is not the recommended one, not quite correct, but it is possible to do for the excersize... When I say lathe, lathe may be verry simple, someting like turns, but made of what one has in reach of his hands. If You want to try, I will try to guide
    • JohnR725
      Without Our Forum

      By JohnR725 · Posted

      yes by all means let's gather up our weapons tar feathers find the nearest tree in case Mark is not agreeable to our terms on our demands and storm his Castle. I don't quite understand what you're trying to do here? In other words you want Mark to somehow guarantee that the group will live on forever no matter what? You want Mark to somehow change his business model of what is trying to do or should we just take the group away from him? oh and is quite possible that Mark never realized that his discussion group would take on a life of its own. That the members of the group would like to continue on forever.  
    • RichardHarris123
      Second hand watch market.

      By RichardHarris123 · Posted

      I'm not sentimental, I see it this way.  I inherit something I  don't like, I could sell it, buy something I do like and remember the person with the new item.  For example, I  inherit a watch ( I haven't), I don't like it, I  buy a watch I do like, every time I look at the watch, I think of the person. 
×
×
  • Create New...