I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

Steve

On 5/31/2012 10:02 AM, Steve B wrote:
I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

Steve



the drill tip has a different angle on it. you can get them at the
plastics shop. i don't think i've ever seen them at a borg.

Brad point bit, very little pressure, medium rpm,
yes backer, always avoid edges, you can be close, but they will crack
over time. cleanout with a counter sink...

On 5/31/2012 1:02 PM, Steve B wrote:
I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

Steve

On 5/31/12 12:02 PM, Steve B wrote:
I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

Steve



All of the above, except high rpm. Go slow. Brad point bits helps.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

On 5/31/12 12:13 PM, tiredofspam wrote:
always avoid edges, you can be close, but they will crack
over time.

For close to the edge, I've used a soldering iron to melt holes in thin
plexi.
Also, you could drill the holes in a larger piece, first, then cut to
size.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

"Steve B" wrote in message
...
I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is
there a secret? Sharp blade? High rpm? Very easy pressure? Use a
backer piece of plywood? All the above?

http://www.eplastics.com/Plastic/Ple...tic_Drill_Bits

On Thu, 31 May 2012 10:02:51 -0700, "Steve B"
wrote:

I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

Steve


A drill bit with the right grind?

http://www.rplastics.com/plasticdrill.html

http://www.amazon.com/s?ie=UTF8&tag=...Mozilla-search

On 5/31/2012 10:02 AM, Steve B wrote:
I got a 6" square 1/8" piece of plexi to mount the switches on my boat.
It
will be set into a 3/4" piece of plywood that I routed out, and stained
and
varnished.

I have never had much luck drilling plexi without having it split. Is
there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer
piece
of plywood? All the above?

Why plexi? Lexan (polycarbonate) is much more forgiving. It is also more
flexible and will stand up to more shock and abuse. And it is much easier
to drill. For such a small piece, you can get something at the borg and cut
it to size with any kind of woodworking saw. I have built a lot of stuff
with lexan. Most of the applications I used would have broken the
Plexiglas. Plexi is not only easy to break, but it can develop cracks over
time. Lexan will change its size slightly with temperature changes, but its
increased strength and durability make it more feasible for many
applications. And if this is going on a boat, I would want something a
little stronger and easier to work with.

My advice, toss the plexi and use lexan instead.

On 5/31/2012 1:47 PM, Lee Michaels wrote:

On 5/31/2012 10:02 AM, Steve B wrote:

I have never had much luck drilling plexi without having it split. Is
there a secret?

Why plexi? Lexan (polycarbonate) is much more forgiving. It is also more
flexible and will stand up to more shock and abuse. And it is much
easier to drill. For such a small piece, you can get something at the
borg and cut it to size with any kind of woodworking saw. I have built a
lot of stuff with lexan. Most of the applications I used would have
broken the Plexiglas. Plexi is not only easy to break, but it can
develop cracks over time. Lexan will change its size slightly with
temperature changes, but its increased strength and durability make it
more feasible for many applications. And if this is going on a boat, I
would want something a little stronger and easier to work with.

My advice, toss the plexi and use lexan instead.

Bingo ... second the use of Lexan over plexiglass, although it can get
pricey.

I can cut it on the TS with my Forrest WWII, and have drilled it (albeit
small holes for screws) with whatever was in my tool box.

Used Lexan for this "no visible means of support" backlit art glass
shelf for a client, cut to size on the table saw from a 4 x 8 sheet,
about a year ago:

https://picasaweb.google.com/1113554...237981688 482

(cell phone photos, sorry)

--
www.eWoodShop.com
Last update: 4/15/2010
KarlCaillouet@ (the obvious)
http://gplus.to/eWoodShop

On 5/31/2012 12:02 PM, Steve B wrote:
I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

Steve



Start with a small hole and work up.

Steve B wrote:

I got a 6" square 1/8" piece of plexi to mount the switches on my
boat.
----------------------------
Plexiglass and boats don't mix.

Use Lexan.

Lew

On Thu, 31 May 2012 10:02:51 -0700, Steve B wrote:

I have never had much luck drilling plexi without having it split. Is
there a secret? Sharp blade? High rpm? Very easy pressure? Use a
backer piece of plywood? All the above?

There are special bits, but I've had pretty good luck with a plywood
sandwich.

--
Intelligence is an experiment that failed - G. B. Shaw

On Thu, 31 May 2012 10:04:28 -0700, chaniarts
wrote:

On 5/31/2012 10:02 AM, Steve B wrote:
I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

With normal metalworking twistbilldrits, use low RPM, light touch,
sharp edges. Backer boards are a very good idea, too. Some forstner
bits work well (small diameter), others don't (like sawtooth styles).


the drill tip has a different angle on it. you can get them at the
plastics shop. i don't think i've ever seen them at a borg.

Aha! I didn't know that one.

I used to drill square holes in plastic dashboard with an air drill
and twistbilldrits, but that's not plexi. (I think it was ABS.) I
worked in Phoenix one summer (what an idiot!) installing air
conditioners in brand new trucks. One 118F day, it was only 108 in
the shop with 4 humongous swamp coolers running.

--
Self-development is a higher duty than self-sacrifice.
-- Elizabeth Cady Stanton

There is help below - but Dad and I always used a ring of clay -
modeling type - oil base - and water inside. It keeps the plastic
cool - and pec drill. Keep the tips slow. RPM's slow. A fast
turning tip of a drill - the outer cutting edge - can melt plastic
and then it cracks it.

Martin

On 5/31/2012 12:02 PM, Steve B wrote:
I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

Steve

On Thu, 31 May 2012 15:38:00 -0500, Leon lcb11211@swbelldotnet
wrote:

On 5/31/2012 12:02 PM, Steve B wrote:
I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

Steve

Start with a small hole and work up.

That's the _opposite_ of what she said. domg

LJ, humming "Lay 'er down, roll 'er over, and do it again."

--
Self-development is a higher duty than self-sacrifice.
-- Elizabeth Cady Stanton

"Steve B" wrote in message ...

I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

**********************
Modify a regular twist bit. The leading edge of the cutting surface of a
normal bit is several degrees, and helps lift the chips away from the cut
and also pulls the bit into the material. That is what you do not want.
Take a cutoff wheel on a dremel tool, and cut that leading edge so it is at
89 or 90 degrees to the material you are cutting. Then, take a little
paint, like white or orange, and paint down in the flutes, so it will be
easy to identify later, and not used for cutting other stuff, and getting
thrown away.
Works well, every time.

-- Jim in NC

"Morgans" wrote in message ...

"Steve B" wrote in message ...

I got a 6" square 1/8" piece of plexi to mount the switches on my boat. It
will be set into a 3/4" piece of plywood that I routed out, and stained and
varnished.

I have never had much luck drilling plexi without having it split. Is there
a secret? Sharp blade? High rpm? Very easy pressure? Use a backer piece
of plywood? All the above?

**********************
Modify a regular twist bit. The leading edge of the cutting surface of a
normal bit is several degrees, and helps lift the chips away from the cut
and also pulls the bit into the material. That is what you do not want.
Take a cutoff wheel on a dremel tool, and cut that leading edge so it is at
89 or 90 degrees to the material you are cutting. Then, take a little
paint, like white or orange, and paint down in the flutes, so it will be
easy to identify later, and not used for cutting other stuff, and getting
thrown away.
Works well, every time.
================================================== ================================
I agree. I have done production drilling on plexi. A neutral rake on a twist
drill works great.

In ,
Morgans typed:
"Steve B" wrote in message
...
I got a 6" square 1/8" piece of plexi to mount the
switches on my boat. It will be set into a 3/4" piece of
plywood that I routed out, and stained and varnished.

I have never had much luck drilling plexi without having
it split. Is there a secret? Sharp blade? High rpm? Very easy pressure?
Use a backer piece of plywood? All
the above?
**********************
Modify a regular twist bit. The leading edge of the
cutting surface of a normal bit is several degrees, and
helps lift the chips away from the cut and also pulls the
bit into the material. That is what you do not want.
Take a cutoff wheel on a dremel tool, and cut that
leading edge so it is at 89 or 90 degrees to the material
you are cutting. Then, take a little paint, like white
or orange, and paint down in the flutes, so it will be
easy to identify later, and not used for cutting other
stuff, and getting thrown away. Works well, every time.

-- Jim in NC
I tried that for grins; and it fails miserably. Std drill bit will work as
below:

Backer piece plus tape applied to the other side where the hole will be has
always worked well here. Speed slow enough to let it cut before it burns the
plastic. Need a sharp bit.

"Twayne" wrote in message ...

In ,
Morgans typed:
"Steve B" wrote in message
...
I got a 6" square 1/8" piece of plexi to mount the
switches on my boat. It will be set into a 3/4" piece of
plywood that I routed out, and stained and varnished.

I have never had much luck drilling plexi without having
it split. Is there a secret? Sharp blade? High rpm? Very easy pressure?
Use a backer piece of plywood? All
the above?
**********************
Modify a regular twist bit. The leading edge of the
cutting surface of a normal bit is several degrees, and
helps lift the chips away from the cut and also pulls the
bit into the material. That is what you do not want.
Take a cutoff wheel on a dremel tool, and cut that
leading edge so it is at 89 or 90 degrees to the material
you are cutting. Then, take a little paint, like white
or orange, and paint down in the flutes, so it will be
easy to identify later, and not used for cutting other
stuff, and getting thrown away. Works well, every time.

-- Jim in NC
I tried that for grins; and it fails miserably.
================================================== ===================================
Then you ground it wrong.

"CW" wrote in
m:



"Morgans" wrote in message
...

"Steve B" wrote in message
...

I got a 6" square 1/8" piece of plexi to mount the switches
on my boat. It will be set into a 3/4" piece of plywood
that I routed out, and stained and varnished.

I have never had much luck drilling plexi without having it
split. Is there a secret? Sharp blade? High rpm? Very
easy pressure? Use a backer piece of plywood? All the
above?

**********************
Modify a regular twist bit. The leading edge of the
cutting surface of a normal bit is several degrees, and
helps lift the chips away from the cut and also pulls the
bit into the material. That is what you do not want. Take
a cutoff wheel on a dremel tool, and cut that leading edge
so it is at 89 or 90 degrees to the material you are
cutting. Then, take a little paint, like white or orange,
and paint down in the flutes, so it will be easy to
identify later, and not used for cutting other stuff, and
getting thrown away.
Works well, every time.
================================================== =========
=
====================== I agree. I have done production
drilling on plexi. A neutral rake on a twist drill works
great.


That's how I've done it...especially if I want to tap the
hole. The bits sold by the plastics vendors come in only a
few fractional sizes. I have a set of number bits (tap and
clearence sizes) that I've ground a small flat on the lip,
parallel to the bit axis, so it produces a "scraping" action,
rather than the "shearing" action of normal twist drill bits.
Backing, slow speed, and gentle feed...especially on
breakout. These are also great for drilling brass.
I do have a set of commercial plastics bits (1/8"-1/2"), and
the point angle on them is smaller than twist drills. But
mine work great.

Ken

While not a pro way, a circular dam that holds a small amout
of water over the hole site as the drill pecks a hole into
the glass.

Must keep the speed down as the plastic melts. The linear
movement of the circumference is what gets you. The outside
really whips around. But in water it will keep the drill
and plastic cool. Just keep adding drips of water to keep
it full. When the hole is drilled, the water drops through.

Remember it is inches per minute that is important, not RPM.
Slow down the large drills even more than the small ones.

Martin

On 6/3/2012 1:10 PM, CW wrote:


"Twayne" wrote in message ...

In ,
Morgans typed:
"Steve B" wrote in message
...
I got a 6" square 1/8" piece of plexi to mount the
switches on my boat. It will be set into a 3/4" piece of
plywood that I routed out, and stained and varnished.

I have never had much luck drilling plexi without having
it split. Is there a secret? Sharp blade? High rpm? Very easy
pressure? Use a backer piece of plywood? All
the above?
**********************
Modify a regular twist bit. The leading edge of the
cutting surface of a normal bit is several degrees, and
helps lift the chips away from the cut and also pulls the
bit into the material. That is what you do not want.
Take a cutoff wheel on a dremel tool, and cut that
leading edge so it is at 89 or 90 degrees to the material
you are cutting. Then, take a little paint, like white
or orange, and paint down in the flutes, so it will be
easy to identify later, and not used for cutting other
stuff, and getting thrown away. Works well, every time.

-- Jim in NC
I tried that for grins; and it fails miserably.
================================================== ===================================

Then you ground it wrong.

Martin Eastburn wrote in
:

While not a pro way, a circular dam that holds a small amout
of water over the hole site as the drill pecks a hole into
the glass.

Must keep the speed down as the plastic melts. The linear
movement of the circumference is what gets you. The outside
really whips around. But in water it will keep the drill
and plastic cool. Just keep adding drips of water to keep
it full. When the hole is drilled, the water drops through.

Remember it is inches per minute that is important, not RPM.
Slow down the large drills even more than the small ones.

Martin

On 6/3/2012 1:10 PM, CW wrote:


"Twayne" wrote in message ...

In ,
Morgans typed:
"Steve B" wrote in message
...
I got a 6" square 1/8" piece of plexi to mount the
switches on my boat. It will be set into a 3/4" piece of
plywood that I routed out, and stained and varnished.

I have never had much luck drilling plexi without having
it split. Is there a secret? Sharp blade? High rpm? Very easy
pressure? Use a backer piece of plywood? All
the above?
**********************
Modify a regular twist bit. The leading edge of the
cutting surface of a normal bit is several degrees, and
helps lift the chips away from the cut and also pulls the
bit into the material. That is what you do not want.
Take a cutoff wheel on a dremel tool, and cut that
leading edge so it is at 89 or 90 degrees to the material
you are cutting. Then, take a little paint, like white
or orange, and paint down in the flutes, so it will be
easy to identify later, and not used for cutting other
stuff, and getting thrown away. Works well, every time.

A touch of soap in the water also helps.

The problem with drilling most plastics is that they have a nasty
combination of poor thermal conductivity, and high thermal expansion.
That means that once the material starts getting hot, it wants to expand,
but the only place it can go is towards the drill. If the thermal
conductivity was higher, the hole would actually get bigger as the whole
piece expanded. The inward expansion creates more friction, which begats
more expansion, and you can rapidly get a runaway condition leading to
the drill grabbing. You have to keep the plastic & the drill cool enough
that it nevers gets into the runaway condition. Slows speeds, pecking,
and coolant all help.

Doug White

Wow, a real BM storm, a strain @ a gnat, a complication where none
exists.
I drill PC & AC & a lot of other materials; I'm a driller. With a
plexi drill, and the work immobilized, you advance the spinning drill
into the work and make a hole. The exit is as clean as the entry;
what's the deal?
No goo, no lube no clay dams, no diddly, see:
http://patwarner.com/images/machining_plastic_d.jpg

"Doug White" wrote in message
. ..

Martin Eastburn wrote in
:

While not a pro way, a circular dam that holds a small amout
of water over the hole site as the drill pecks a hole into
the glass.

Must keep the speed down as the plastic melts. The linear
movement of the circumference is what gets you. The outside
really whips around. But in water it will keep the drill
and plastic cool. Just keep adding drips of water to keep
it full. When the hole is drilled, the water drops through.

Remember it is inches per minute that is important, not RPM.
Slow down the large drills even more than the small ones.

Martin

On 6/3/2012 1:10 PM, CW wrote:


"Twayne" wrote in message ...

In ,
Morgans typed:
"Steve B" wrote in message
...
I got a 6" square 1/8" piece of plexi to mount the
switches on my boat. It will be set into a 3/4" piece of
plywood that I routed out, and stained and varnished.

I have never had much luck drilling plexi without having
it split. Is there a secret? Sharp blade? High rpm? Very easy
pressure? Use a backer piece of plywood? All
the above?
**********************
Modify a regular twist bit. The leading edge of the
cutting surface of a normal bit is several degrees, and
helps lift the chips away from the cut and also pulls the
bit into the material. That is what you do not want.
Take a cutoff wheel on a dremel tool, and cut that
leading edge so it is at 89 or 90 degrees to the material
you are cutting. Then, take a little paint, like white
or orange, and paint down in the flutes, so it will be
easy to identify later, and not used for cutting other
stuff, and getting thrown away. Works well, every time.

A touch of soap in the water also helps.

The problem with drilling most plastics is that they have a nasty
combination of poor thermal conductivity, and high thermal expansion.
That means that once the material starts getting hot, it wants to expand,
but the only place it can go is towards the drill. If the thermal
conductivity was higher, the hole would actually get bigger as the whole
piece expanded. The inward expansion creates more friction, which begats
more expansion, and you can rapidly get a runaway condition leading to
the drill grabbing. You have to keep the plastic & the drill cool enough
that it nevers gets into the runaway condition. Slows speeds, pecking,
and coolant all help.
================================================== =======================
The right speed and the right drill bit is all that is needed.

"routerman" wrote in message
...


Wow, a real BM storm, a strain @ a gnat, a complication where none
exists.
I drill PC & AC & a lot of other materials; I'm a driller. With a
plexi drill, and the work immobilized, you advance the spinning drill
into the work and make a hole. The exit is as clean as the entry;
what's the deal?
No goo, no lube no clay dams, no diddly, see:
http://patwarner.com/images/machining_plastic_d.jpg
================================================== =====================
I agree completely.

Tap also.
Hum.

Ok - where are the plastic drills you use.
Plastic taps also ?

Martin

On 6/6/2012 5:17 PM, routerman wrote:

Wow, a real BM storm, a strain @ a gnat, a complication where none
exists.
I drill PC& AC& a lot of other materials; I'm a driller. With a
plexi drill, and the work immobilized, you advance the spinning drill
into the work and make a hole. The exit is as clean as the entry;
what's the deal?
No goo, no lube no clay dams, no diddly, see:
http://patwarner.com/images/machining_plastic_d.jpg