Kinda off-topic, but good to know...
Just thought I'd interject something here that I remember Bill Benner of Pangolin talking about at one of the Florida Laser Enthusiast's Meetings a while back...
We were talking about how the mirror thickness affects the maximum scanner speed, and the point was that while a thinner mirror will have lower mass, and thus you would think it would be better for high-speed scanning because less mass = faster speed, it turns out that the rotor is much heavier than the mirror. So much so, in fact, that the weight of the mirror is almost inconsequential.
But there *is* a problem with using thin mirrors: Resonance. Turns out that at high scanner speeds, the mirror can actually flex and vibrate (especially if it's too thin), and this causes distortion in the scanned image. So having mirrors that are too thin can actually be a problem. Bill pointed out that some of the older Chinese clones of the Cambridge 6800's had very thin mirrors, and they suffered from this problem.
Fortunately, if you install thin mirrors and end up with a resonance problem, there is a quick and easy fix for this... Just apply some fast-drying 2-part epoxy to the back side of the mirror. When it dries, this will add stiffness to the mirror, stopping the resonance. And remember, the tiny bit of extra weight won't make any real difference in the scan speed.
Bill did mention that if you do this "Epoxy trick", you might need to re-tune the scanner amps slightly, as you may need less damping once you've stiffened the mirrors. But it's definitely safe, and it works. (I did it with an old set of DT-40 scanners that I had to replace the mirrors on years ago, and it worked great. Didn't even have to re-tune!)
Just thought it might be helpful to anyone buying new mirrors for their scanners... I'm not saying that these mirrors are too thin, but in the odd chance that they do resonate, there's an easy (and permanent) way to fix it!
Adam