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English PW Oiling Gear Train jewels - a basic question

MikePilk

Registered User
Nov 23, 2014
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London
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Sorry to ask something so basic, but there are very few articles/YouTube videos etc on exactly how to oil properly, and as I newbie I feel I might be slapping too much oil where it shouldn't be.

My question is : Which is the best way to oil the gear train jewels (assuming they are not capped)
a) Oil the inside of the jewels before reassembly of the gear train
or
b) reassemble and oil the outside ends of the pivots ?

Thanks
Mike
 

karlmansson

Registered User
Apr 20, 2013
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Linköping, Sweden
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If the jewels are not capped, the way to do it is to assemble the watch after cleaning it completely and then adding oil to the jewels with an oiler. The oil should be applied by contacting the surface right between pivot and jewel, or just where they meet. Usually you only need a very small amount and it varies with the size of the movement and the size of the pivot. There should absolutely not be more than will fit in the oil cup of the jewel. I think I got the tip to keep lubrication to a minumum where a thin edge of oil is visible between pivot and jewel. the rest of the applied oil is drawn down towards the pinion flank and kept in place by capillary action.

After oiling, if you need to take the movement apart again the plate and pivots should ideally be replaced again to prevent migration of the oil.

For capped jewels you can either place a small drop of oil on the cap jewel and then assemble the setting or you can place a drop from the "pivot side" of the jewel and then insert a very fine, pointed oiler into the hole to draw the oil onto the cap.

Best

/Karl
 

gmorse

NAWCC Member
Jan 7, 2011
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Hi Mike,

Your option "b" is certainly the recommended method; option "a" risks oil getting where it's not needed, and also over-oiling. Have a look at this publication from the BHI:

View attachment Practical_Lubrication_2008.pdf

A useful guide is that if you can see a pool of oil, it's far too much.

Regards,

Graham
 

psfred

Registered User
Sep 25, 2009
975
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The ideal amount of oil on a "plain" pivot fills the space around the pivot inside the jewel and extends a very thin film of oil almost to the outside of the shoulder on the pivot that rides on the flat side of the jewel. Oil must not form a meniscus around the shoulder nor should it "pool" in the hole in the jewel, just fill the space. This provides as much lubrication (and friction reduction) as possible. More oil will cause drag and will migrate around, plus free oil (a meniscus around the shoulder, for instance) will collect dust causing even more friction.

Needless to say you cannot see this with the watch assembled, so if you have a watch that is easy to remove and replace the gear train, you should get the proper sized oilers, clean all the oil off of everything, assemble, oil the train, let it spin a bit, then take the watch apart and check the oil patches on the jewels. A time or two of oiling, being careful to use the oilers correctly and trying different sizes, etc should give you a good feel for how much oil is the correct amount.

Each movement will be different, although a general rule is that higher quality watches tend to have tighter tolerances and hence need less oil, but a bit of practice should get you on the right track.

Watches require VERY small amounts of oil, don't be surprised if you grossly over-oil to start with.

I still tend to put too much oil on pivots.

Peter
 

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