Replacement domed acrylic crstal

[Mlgboy]

Hi All, looking for some help identifying the correct crystal type for a Tudor Advisor Alarm ref 7926 circa 1958. The watch has a retaining bezel over the crystal which is .5mm thick with an outer non stepped diameter of 29.4mm. Overall height is 3.7mm. Any help would be much appreciated.

Mark

[jdm]

These are called top glasses.

https://www.cousinsuk.com/product/domed-top-sternkreuz-st

They may need a slight sanding to fit. Download and check the catalog.

[Mlgboy]

On 9/15/2019 at 2:34 PM, jdm said:

These are called top glasses.

https://www.cousinsuk.com/product/domed-top-sternkreuz-st

They may need a slight sanding to fit. Download and check the catalog.

Found the correct inside diameter at 28.4 with an outside diameter of 29.7 and actually need 29.4. Any recommendations for reducing the size accurately while leaving a clean finish?

[jdm]

I would use a fine sanding block, sponge type or paper on wood. A so small difference is done easily, check often the bezel fitting to not remove too much. 

[Mlgboy]

Big thanks to JDM for the idea with the sanding block. Ended up 3D printing a holder to support the crystal in a drill press so i could reduce the outer diameter while it was rotating. Worked perfectly.

Edited April 16, 2020 by Mlgboy