Drilling holes in Plexiglass for Control Panel

[dmish82]

I am about to get some plexiglass for my control panel and was wondering the best way to go about drilling holes for the buttons and joysticks in the plexiglass? I used a hole saw for the wood and was wondering if that will work on the plexiglass or if any better or more careful methods should be used. Thanks.

[Hoagie_one]

many have said a spade bit, drilling in reverse and melting your way through is the best, but i havent tried it personally

[Xiaou2]

Cutting plexi is tricky.. but not that bad.

  The biggest troubles arise if you do not
clamp the material.  Any vibrations will cause
the fractures.

1) Keep plexi covering on till your finished - else
it will  scratch while your working on it.

2) Clamp plexi to the control panel.  Use a soft
clamp, or pop something like a folder rag in the
jaws to avoid scratches from the clamps.

3) Drill using a drill guide to reduce vibrations..
or better - use a drill  press.  Trying to freehand
drill will most likely result in cracking as even a
small kick or varience in your cutting angle will
cause a crack.

4) Bit selection:
  a) Fostner bit = cleanest smoothest cuts!
      but most expensive bits.  A little slow to cut

  b) Spade Bit - very fast cutting, nice holes.  
        Need drillguide or press to use well.
        Cheapest bits. (buying a full set is usually less
        costly overall, and nice to have all the sizes)

    c) Holesaw - med speed holes.  Have to unclog the
        bit each holes. A little rough.  Get a dedicated bit
        rather than a multi head  interchangable one as
        they arnt very durrbale, will break fast.  bi-metal
        will cut thru all: metal, wood, plexi.  Good bits are
          fairly costly, but will last a long time.

    d) Circle cutter - a little tricky to use..  needs a drill
        press to use.  Good for obscenely large holes.

*** Drill tips:

Drill at HIGHEST speed setting - BUT - drill
down as SLOW as possible.  Letting the
speed of the drill heat the plexi to the point
of making it melt slightly so that it will not
crack.  Some drill in reverse - but thats not
nessessary... and still can cause a crack if you
drill too fast downwards.  A drill hole that
would take about 1 second in a harder
material,  would take about 10 or more
seconds to avoid cracks.

5)  Drill a hole that will be for a bolt that
      will hold the plexi to the panel.  Once that
      is drilled, pop the bolt in and lightly tighten it.  
      Do each of the corners one at a time this way.  
    This will help to keep the the material in place
      and might even choose to remove the clamps
      afterwords

  6) Drill the Plexi and the control panel hole at
      the same time to reduce problems with
      wandering (where plexi holes and wood holes
      dont line up well).  OR

  6b) Drill a the panel from the bottom, but,  
        must add another piece of wood to the
        bottom & clamp that as well (making a
        plexi sandwhich).  OR

  6c) Drill pilot holes,  then use a router to
        cut the rest - following the edges.  A 1/4"
        rotozip bit gets good results... hadnt
        tried a standard bit.
 
  7) Smooth edges of holes by lightly hand
        sanding them with a high grit paper.

Cutting Edges:

  Routers will work great for this.

  I have cut plexi with a tablesaw tho - and it
does work...  but its messy and chips the edges
a bit.  It may have been better if I had tried to
sandwhich the plexi in between wood before
the cut - but didnt think about that at the time.

  Scoring does work as well.  Clamp a straight
edge to the plexi, then run razorblade across
the edge into the plexi.  you will need to repeat
this several times.  After getting fairly deep into
the material... you may then try to break the
parts appart.  Make sure to clamp the halves
tightly so that one of the edges is overhung
over a table edge or simular.

Scoring may still need a good deal of sanding
and maybe some shapeing.  I recomend
practicing this a few times before the actual
piece.