I would like to replace the bezel insert on my diver watch but it seems impossible to find one with the right dimensions, I need 39,7mm OD and 32.4mm ID. Is there any place that sells custom bezel? I have found a OD39.5mm and ID32.2mm bezel but it's .2mm smaller so I suppose it will not fit on it.
I think you meant bezel "insert." I've tried. There's some interchangeability within a brand, but that's about it. The inner diameter can be slightly larger but you'll see a gap; outer diameter must be exact. Thickness matters too. Best to get a replacement labeled specifically for the watch.