Just a warning:
I wouldn't worry about my fingers. (i have plenty of those) I would enclose the whole thing
in an non-see-through box only to protect my eyes. Even of you don't cut (very reflective!)
metal, plastics can be shiny to ! and I expect that all your clamps are painted matt-black ?
1 mW lasers are considered "save" because most people have a < 0.25 second
reflex that closes there eye lids. If you have a 100 W laser, you have 0.0000025 seconds
to close your eyes, meaning: you will be to late, even if an object only reflects 1% of the
laser power. you do wear glasses matching the laser wavelength do you ?