Cutting Lenses - What Works

[kronin323]

Did you cut them yourself?

IH cut me a pair once where the orientation was mismatched, they were unwearable and I had to get them replaced. You can test the relative orientation easily enough using the LCD test.

 

[kronin323]

I can’t see how it’s not possible to align the new lenses over the old while keeping the lenses symmetrical to each other.

I didn't say it was impossible, just that one was most likely to screw it up. Even fractions of degrees matter.

 

[Lupetto]

I wonder if a micrometer might be enough to align the lenses over the old.

Now I want to try, just need tools. What dremel is recommended? What wet sandpaper grit should be used?

 

[Scarface]

Yes. Oakley specifically cuts both lenses from the same blank to ensure the polarization orientation on both is identical. When they aren't you get increasing levels of that "rainbow effect" and other uncomfortable disorientation effects. And I speak from practice, not just theory.

I did a test now in front of my LCD Screen.

When i look through the lenses and turn them ccw it goes dark around 45°
When i turn them cw it goes dark around 180°

It's same on the 5 glasses i tried now.

Original Tincan Ferrari
Original Carbon Prime
Original Carbonshift

Penny custom OEM BIP lenses (bought from Chris 51500 so idk who cutted them)
Juliet Custom OEM DWP lenses (i did cut these self)

@kronin323, do you know why one side is around 45 and the other side 180°?
DWP i cut self behave exactly as the original lenses. I was very careful with the orientation when I cut them.

 

[Lupetto]

I did a test now in front of my LCD Screen.

When i look through the lenses and turn them ccw it goes dark around 45°
When i turn them cw it goes dark around 180°

It's same on the 5 glasses i tried now.

Original Tincan Ferrari
Original Carbon Prime
Original Carbonshift

Penny custom OEM BIP lenses (bought from Chris 51500 so idk who cutted them)
Juliet Custom OEM DWP lenses (i did cut these self)

@kronin323, do you know why one side is around 45 and the other side 180°?
DWP i cut self behave exactly as the original lenses. I was very careful with the orientation when I cut them.

Yeah , probably careful measurement a steady hand and a bit of luck !!

 

[Scarface]

I wonder if a micrometer might be enough to align the lenses over the old.

Now I want to try, just need tools. What dremel is recommended? What wet sandpaper grit should be used?

Mate, it does not matter what Dremel model you use, mine is several years old so there is newer model out there. (It's the round/small one in that picture)

I used 800 and then 1200 grit wet sandpaper, i think SoulFulFrog using 2000 grit...

 

[kronin323]

@kronin323, do you know why one side is around 45 and the other side 180°?

The light from LCD screens is polarized as an innate result of how the technology functions. You get the darkening effect during the test when you rotate them to the angle that aligns the polarization filter of the lenses with the polarized light from the screen. At what angle the polarized light is oriented from an LCD may vary from one screen to another but regardless of whether you're rotating the glasses cw or ccw they should darken at the same angle, both right-side-up and upside-down.

But the key in this context is that both lenses darken at identical angles. If one darkens before the other, even by a little bit, then they've become mismatched.

 

[Scarface]

The light from LCD screens is polarized as an innate result of how the technology functions. You get the darkening effect during the test when you rotate them to the angle that aligns the polarization filter of the lenses with the polarized light from the screen. At what angle the polarized light is oriented from an LCD may vary from one screen to another but regardless of whether you're rotating the glasses cw or ccw they should darken at the same angle, both right-side-up and upside-down.

But the key in this context is that both lenses darken at identical angles. If one darkens before the other, even by a little bit, then they've become mismatched.

I assumed that I got a correct explanation from you mate
Then, it has something to do with my LCD screen, all of them behave exactly the same, 3 original and the other 2 that are Custom Cut.
But as you said 1-2° , you cant see that difference on the screen by rotating it, but will affect your viewing/vision.

 

[Scarface]

I found out now, if i start at 45° angle to the left on the LCD screen, then they shift to dark exactly the same place when i rotate them left or right from that angle.

 

[kronin323]

I assumed that I got a correct explanation from you mate
Then, it has something to do with my LCD screen, all of them behave exactly the same, 3 original and the other 2 that are Custom Cut.
But as you said 1-2° , you cant see that difference on the screen by rotating it, but will affect your viewing/vision.

It's probably worth mentioning that there's two aspects of preserving the polarization orientation when cutting.

One is that you preserve the correct orientation relative to the environment. Oakley's are oriented to block reflected light from below you, such as the hood of a car or a wet road. You can test if you got that right by doing the LCD test and ensuring the cut lenses darken at the same angle as a known good OEM set.

The other is that you preserve identical orientation relative to each lens. That is tested by ensuring they both identically darken at the same angle during the LCD test. This is the aspect that I've been talking about in recent posts here.