Recently I have been upgrading a couple of my Tudor Submariners with bezel assembles from Clarks. Although they need to be polished these are significant improvement over those that come on bivintage cases. As they come the tolerances throughout are very tight and the retaining ring will not press in place with any xtal I have used. Hand sanding is slow and there is a chance of doing it unevenly thus causing a poor fit and deforming the xtal.
I realized I needed something that was very close in diameter to the inside diameter of the retaining ring that could be used to hold sandpaper that I could spin in a drill. After digging through my garage I located a ¾ piece of PVC pipe as well as a long bolt and hardware. I assembled so the pipe was centered between the washers and then torqued the nut down enough that the washers just began to dig into the plastic. I used a lockwasher to prevent it from loosening up when spinning. To slightly increase the OD of the pipe I cut a chinet (heavy duty paper plate) plate up so it could be securely wrapped and taped around the pipe, then I slipped 100 grit sandpaper over it and held it place with a rubber band. At this point then retaining ring slid over the assembly snugly but could turn independently of it. Using a pair of gloves (it gets hot and if you hand contacts the sandpaper you will get tore up) I held the retaining ring and started the drill, doing intervals of about 10 seconds to allow for cooling and measuring using calipers. When measuring I marked the ring every 90 degrees and measured across each mark and halfway between each one as well to ensure its ID remained constant. When I noticed one dimension being off slightly (100th of an mm) I marked it and applied pressure at that location so it would be sanded more.
After I reduced the ID close enough to what I needed I checked it on the watch, after waiting for it to cool. Another interval of sanding and it was good to go and I could press it in place.
After the watch was assembled I pressure tested it and it held to as high as my tester would go.
Hopefully someone else will be able to use this to build, or improve, their watch.
The sander - it is slighty off center in the second picture, I centered it before using it:
With the ring and ready to start:
Measuring:
Note marks every 90 degrees:
Pressure test:
I realized I needed something that was very close in diameter to the inside diameter of the retaining ring that could be used to hold sandpaper that I could spin in a drill. After digging through my garage I located a ¾ piece of PVC pipe as well as a long bolt and hardware. I assembled so the pipe was centered between the washers and then torqued the nut down enough that the washers just began to dig into the plastic. I used a lockwasher to prevent it from loosening up when spinning. To slightly increase the OD of the pipe I cut a chinet (heavy duty paper plate) plate up so it could be securely wrapped and taped around the pipe, then I slipped 100 grit sandpaper over it and held it place with a rubber band. At this point then retaining ring slid over the assembly snugly but could turn independently of it. Using a pair of gloves (it gets hot and if you hand contacts the sandpaper you will get tore up) I held the retaining ring and started the drill, doing intervals of about 10 seconds to allow for cooling and measuring using calipers. When measuring I marked the ring every 90 degrees and measured across each mark and halfway between each one as well to ensure its ID remained constant. When I noticed one dimension being off slightly (100th of an mm) I marked it and applied pressure at that location so it would be sanded more.
After I reduced the ID close enough to what I needed I checked it on the watch, after waiting for it to cool. Another interval of sanding and it was good to go and I could press it in place.
After the watch was assembled I pressure tested it and it held to as high as my tester would go.
Hopefully someone else will be able to use this to build, or improve, their watch.
The sander - it is slighty off center in the second picture, I centered it before using it:
With the ring and ready to start:
Measuring:
Note marks every 90 degrees:
Pressure test:
