Let's talk methodology in the cutting of a decently clean hole. Get a piece
of plywood that is slightly larger than the piece of plexi or whatever you
are going to work on. Get a couple of C clamps also. Now, lay the plexi on
top of the plywood, and clamp the whole thing onto the workbench with the C
clamps. (This is why it's better to cut the plexi to size afterwards, since
you will have an extra edge to clamp to, so you dont care if you mar it with
the clamps.) You can then drill the holes fairly accurately, without making
a big mess. Stability of the work pieces is of paramount importance here, if
you want a quality job. Another trick commonly used in the woodworking shop
to reduce rough edges around the hole is to lay another piece of plywood on
TOP of the plexi before drilling it. This reduces the "tear out" and melting
around the edges of the hole. Drill small 1/8 inch guide holes in the exact
centers of where you want the holes FIRST. This will tend to stabilize and
center the hole saw when starting the hole.

If you have a router and circle cutter attachment around the shop, then you
can neatly sidestep the entire "hole saw and driill" debacle, since the
router, with a straight bit , will cut a MUCH cleaner hole than any hole
saw.. Just drill the centering holes, and put the circle cutter on there,
and cut the hole, routing out about 1/8 inch of depth on each turn. No
burning, no melting. (Clockwise rotation, please) The same discussion on
clamping applies here, also. The difference here is that you dont have to
apply any pressure to the router when cutting, like you would with a hole
saw. The router actually cuts the material out of it's way as it goes. Very
little, if any, dressing of the hole edges will be needed afterwards.

"Rick Mintz" wrote in message
...
Hi.

I am building an amp and will be using a clear plastic over the front
panel graphics.

I could use some help in choosing the material, such as Plexi or Lexan.
Since I will be drilling couple of 2" holes to mount panel meters, I need
some suggestions for which material is the best to work with. A hole saw
in Plexi is prone to crack and maybe there is a better choice. There also
may be a better method for creating the holes than a standard hole saw.
Suggestions???

de Rick W1TY

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