First, the good news:

• This summer, Stephen recorded a 41+ meter dive with the goggles, confirming that the design is sound. He complained about aberrations in his visual field that I have not had time to investigate myself yet. This will be a topic for the v2.
• The chinese groover arrived last august

Of course, since I did not have any spare lens to groove, I had to wait until the fablab re-opened in september, and, then, getting finished with my day job for the past 12 years became a priority until september 15th when, suddendly, plenty of spare time became the new normal.

To make this story short, I cut a new lens, attempted to groove its side, and this is when I discovered that I missed a critical parameter when I bought this nice little machine: the minimal lens diameter that can be grooved is 28mm while the smallest diameter of my lenses is 21.8mm... Ouch.

Hopefully, none of this can't be fixed. I made a couple of cutting, grinding, and 3d-printing modifications to the groover until I was able to groove my first lens yesterday. The result ? On the left, a lens with the old DIY groover, on the right, the modified chinese groover: the one on the right has a noticeably more uniform depth. It looks terrific !

The next step will focus on more modifications to the groover to make it possible to control the width of the groove in a repeatable way.