On Feb 27, 5:47*am, "Grumps" wrote:
Hi

I have a need to screw into some sheets of acrylic. I have some 1/2" #6
screws. I believe this is 3.5mm in metric speak. But is that the hole size I
have to drill?
Ta.

Drill the hole larger so the screw slips right through, use a washer
to take the torque not the screw. Use a new bit and the fastest drill
you have and dont use any force or it will crack, thin plexiglass is
the worst , easiest to crack, 1/8" can easily crack if drilling near
an edge, 1/4" isnt so bad, an old bit and slow drill can catch and
break the plexiglass easily, battery powered drills dont go as fast as
high speed electric drills, I just ruined a bunch of 1/8" plexiglass-
acrilic drilling. When you screw it dont do it real tight, I use a
foam weatherstrip for the seal and only tighten till I see it compress
a bit. That stuff gets expensive when you break it.