Self tapping screw hole

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.

Reply to
Grumps
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Dunno what the right answer is but make sure you choose carefully otherwise you'll get the dreaded "Spider Web" result

Reply to
Usenet Nutter

Acrylic is very brittle and you should tap the holes for metal thread screws. May be 5/32" whitworth use 1/8" drill or metric equivalent.

Reply to
F Murtz

Best way is to measure the shank of the screw. That is near enough the tapping size. Or the outside diameter of the tread and use a drill 1mm smaller at this sort of size.

Reply to
Dave Plowman (News)

test on scrap.

acrylic is quite decent to tap. so a drill slightly bigger than the inner shank, but smaller than the exterior thread diameter, is indicated.

Reply to
The Natural Philosopher

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.

Reply to
ransley

Thanks to all for your comments.

I think I'll tap it instead of using a self tapping screw. Is there a guide/table that gives dimensions of drilled hole for use with particular screw sizes? I'll probably use an M3 screw in this application.

Reply to
Grumps

Lucky size. The tapping drill for that is 2.5mm.

Reply to
Dave Plowman (News)

formatting link

Reply to
emmanuel

Reply to
The Other John

If she's spamming people that posted 8 years ago the business must be pretty desperate.

Reply to
tabbypurr
2010? Is there a time machine about again? Brian
Reply to
Brian Gaff

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