I'm losing loads off my laserworld mirrors in two projectors, about 250mw out of a watt of green...
They are .6mm thickness according to the laserworld manual... I am going to replace them with some I bought from Dave (Lasershow Parts)... The replacements are .7mm, but my guess is that knowing laserworld, the tolerance on the shafts is probably somethind like +/- 1" If they are tight, I will carefully file the groove with a half round needle file...
To summarise, Laserworld mirrors are crap, but we should have guessed that really Therefore if you buy a laser from them, it's underpowered to start with and then the optics and mirrors loosing power as well, probably be better off with a pointer and a bit of tin foil
Mark