First off, the bezel front has two squares of vent holes 
at the bottom and if you set an 80mm fan grill on top of one you will see that the corner holes 
line up almost perfectly with the holes on the grill, almost.  If you try 
putting both grills down at once though you will  notice  the grills 
over lap in the middle and will need to be modded for it all to fit together 
properly, not a big deal.  We need to find the center of the vent hole square, to do this I just lined 
up the corners and used the straight edge to get my lines.  Then, using the 
scribing tool I traced the pencil X over and over until it formed a slight 
depression in the aluminum. 
   
       
      
       
       
    I covered the entire face of the bezel with 
masking tape to prevent scratches caused by metal filings and modding debris, 
masking tape is cheap protection and you should feel free to use it liberally.  
With the front completely covered it is time to drill a couple of pilot holes, a 
task that is no harder than lining up the bit with the scribed mark and drilling 
through. 
   
    I drilled the pilot holes from the front of the 
bezel and used the hole saw on the back side with a 3 1/8" (79mm) hole saw and a 
variable speed drill, which gives a very close to true 80mm hole.  The inner 
edge of most laser cut grills actually line up perfectly with the edge of the 
cut hole... unfortunately the grills that I have are some of the very first offered 
atomic grills, they are a little bigger around than the newer ones and they 
don't line up well.  Since the drilled holes are too small 
I put the grills down on the bezel and used a pencil to trace around the inside 
edge to show how much material still needed to be removed.  If you look closely at the below picture on the 
left compared to the 
picture on the right you can see how much filing was actually involved to make 
the holes the right diameter.  "Why not just use the dremel with a grinding 
wheel instead of the file?"  I knew you would ask and the answer is 
control, a file offers a higher level of precision than a rotary tool and the 
hazards of slipping aren't nearly as great.  Filing takes longer but the finished 
product is entirely worth it. 
   
    Throughout the filing process I would 
continually position the grills on the bezel to see what areas required further 
work, when I was happy with the cuts I held the grills in place and traced 
around the insides of the screw holes.  I used a hobby file to size and 
position the screw holes, I didn't have to remove much material at all and if 
you use thread cutting screws you can actually get away with skipping this step 
but it does make lining them up straight and screwing them in a bit harder. 
    
    Ok, now that everything is cut out and filed 
down we can get on to trimming the inner edges of the laser cut fan grills.  
Since my grills were already modded before I considered writing this guide I 
will walk you through it.  Put both grills down and screw them on, use a 
pencil and mark the spot that overlaps (where the grills come to a V) at the top 
and bottom.  Make sure you mark both grills dark enough that you can see 
the pencil and then unscrew them.  Flip the grills over so that you are 
working from the back side of them and use a straight edge to connect the marks 
on the edges of both grills.  I used a Dremel with a cut off wheel to get 
them cut fairly close and then tested them for fit, it is better to leave a 
little excess and file it off later than take too much off initially with the
Dremel.  I put a couple of black anodized aluminum filters on the back side 
of the bezel and the atomic grills on top and screwed everything down. 
    
    Below is the same mod done to a Lian Li PC-72 
bezel using alien fan grills, on this mod the edges of the hole saw cuts lined 
up perfectly with the inner edges of the grills... no filing involved.  The 
alien grills did require more material be removed than my atomic grills before 
they would sit flush, but the over all finished effect is very much the same.  
Though I tried talking him into aluminum filters for his bezel Marklar decided 
to instead stick with the original filter that came stock with his PC-72 after 
spray painting it to match the aluminum case.  Looks good to me. 
  
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