No, you don't keep it in a "bath" of kerosene. Just take an eyedropper
containing kerosene and put a few drops right where the drill contacts the
glass. Replenish as needed.

"Heinz Schnait" wrote in message
y.telekom.at...
john graesser wrote:

I seem to recall someone mentioning in the past that glass can be drilled
if it was kept in a bath of kerosene, and drilled while submerged.
thanks, John.
KC5DWD

Keep a fire extinguisher ready, when you do this! I would not dare...

73 Heinz, OE5EEP

On Fri, 07 Apr 2006 13:26:30 GMT, "Rick Mintz"
wrote:

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

Email:


2 thoughts

1. If you decide to use the plastic water with a bit of detergent
makes a good coolant/lubricant. Keep the cut flooded.

2. I made a lot of panel covers inthe past by laying out the panel in
Autocad then flipping the drawing layer with the graphics on it to get
a reverse image. I then made an overhead transparency of the graphics
and used the transparency over the metal panel. The result was a clear
plastic cover with the printing sandwiched against the metal panel.
It worked quite nicely. You might want to consider it.

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

Email:

john graesser enscribed:

I seem to recall someone mentioning in the past that glass can be drilled if
it was kept in a bath of kerosene, and drilled while submerged.
thanks, John.

Having the sheet of glass submerged while drilling dampens out the shock
waves and helps to prevent shattering.
However, I don't see what the special attraction would be for using
Kerosene. Plain old water works just fine. Just make sure you use the
correct type of drill bit and a nice slow cutting speed.
Kerosene is not significantly more viscous than water, so if you want to
really damp things out I'd use a heavy grade lube oil, maybe a 20-50
grade motor oil. Far less flammable, as well.

73 Alf NU8I
Scottsdale AZ DM43an

"Alfred Green" wrote in message
news:UIh_f.345$zf6.180@fed1read08...
john graesser enscribed:

I seem to recall someone mentioning in the past that glass can be
drilled if
it was kept in a bath of kerosene, and drilled while submerged.

However, I don't see what the special attraction would be for using
Kerosene. Plain old water works just fine. Just make sure you use the
correct type of drill bit and a nice slow cutting speed.
Kerosene is not significantly more viscous than water, so if you want
to really damp things out I'd use a heavy grade lube oil, maybe a
20-50 grade motor oil.

My experience with Lexan is that oils and/or solvents will cause it to
become very brittle and crack at any machined edges, including drilled
holes.

- Bob W7OV

Bob Headrick wrote:

"Alfred Green" wrote in message
news:UIh_f.345$zf6.180@fed1read08...
john graesser enscribed:

I seem to recall someone mentioning in the past that glass can be
drilled if
it was kept in a bath of kerosene, and drilled while submerged.

However, I don't see what the special attraction would be for using
Kerosene. Plain old water works just fine. Just make sure you use the
correct type of drill bit and a nice slow cutting speed.
Kerosene is not significantly more viscous than water, so if you want
to really damp things out I'd use a heavy grade lube oil, maybe a
20-50 grade motor oil.

My experience with Lexan is that oils and/or solvents will cause it to
become very brittle and crack at any machined edges, including drilled
holes.

The _easy_ way to drill glass is to use a piece of copper tubing with
hole-size for its OD, some powered carborundum as an abrasive, and
just enough water to keep it in a slurry. Use a drill press, low
RPMs, and light pressure.

--
Mike Andrews, W5EGO

Tired old sysadmin