I do not glue the lenses in for the most part. I try to make the lenses a very tight fit in the bezels. Every now and then I get some of the lenses with very bad quality control issues that are smaller than what I turn the bezels to. This requires that I either make new bezels or I glue them in. I would say that this happens maybe 1 out of every 200 lenses. Mostly I make new bezels for a specific color of lens. Injection molding QC is not what I think it should be
I think that I have had to glue maybe 5 or 6 lenses in out of the 2000 bezels that I have made. Now you can see why they take me so long to make