[davehowden]

santasmile

Hi,

Can you tell me how to measure up a watch for a replacement watch crystal please, I see that two numbers are quoted in the form n,nn but I do not know how they are arrived at.


David

:thanks

 

[Henry Hatem]

Hi David,

I am not sure what "form" you are using but you need to have four unknowns to purchase a crystal. Material, Shape, Diameter and Thickness.

Material - ranges from coated Sapphire to plastic.
Shape or style - could range from round & flat to domed glass, rectangular and curved.
Diameter - is just that the diameter needed - caveat - if it is a glass crystal you can measure the bezel and determine what will fit, some plastic crystals are a press or compression fit and you need to know how much.
Last is thickness of the crystal - a piece of the old broken one if flat will be an aid here.

Modern watches with a flat glass crystal are the simplest to demonstrate. When replacing crystals you can choose to get a Sapphire or plastic even add a cyclops (magnifier) for a date. Shape will be round & flat. Diameter is in mm's (for older watches there a couple of measuring systems I will not delve into here) make sure you measure across the center and measure twice - if measuring a bezel measure three times. If the old crystal is available us it for measurement. Last thickness easy enough round flat and measure thickness or bezel step. Of course all this can be simpler if you have a modern watch - most suppliers can furnish a crystal based on the watch brand, style, and case number. Or take your watch to a professional watchmaker and ...well you know the rest.
Let us know how you make out -

 

[lysanderxiii]

Just to further confuse things, Henry forgot to mention that many glass (sapphire and mineral) need gaskets that must be accounted for in the size of the crystal used.

 

[Henry Hatem]

Just to further confuse things, Henry forgot to mention that many glass (sapphire and mineral) need gaskets that must be accounted for in the size of the crystal used.

Excellent point:-! Sneaking under a technicality ;-) "Most" watches with a gasket will have a brand model or case number to order the correct crystal and gasket combination.

Again to your point this is what can happen when dispensing information over the INTERNET missing facts or making assumptions. Call me on it when you see it.

Watchmaking is complex and this is an example of the thread we had on level of understanding and knowledge.