Account Options

  1. Sign in
The old Google Groups will be going away soon, but your browser is incompatible with the new version.
Google Groups Home
« Groups Home
Drilling plexiglass
There are currently too many topics in this group that display first. To make this topic appear first, remove this option from another topic.
There was an error processing your request. Please try again.
flag
  Messages 1 - 25 of 29 - Collapse all  -  Translate all to Translated (View all originals)   Newer >
The group you are posting to is a Usenet group. Messages posted to this group will make your email address visible to anyone on the Internet.
Your reply message has not been sent.
Your post was successful
 
From:
To:
Cc:
Followup To:
Add Cc | Add Followup-to | Edit Subject
Subject:
Validation:
For verification purposes please type the characters you see in the picture below or the numbers you hear by clicking the accessibility icon. Listen and type the numbers you hear
 
Steve B  
View profile  
 More options May 31 2012, 1:02 pm
Newsgroups: rec.woodworking
From: "Steve B" <ste...@gmail.com>
Date: Thu, 31 May 2012 10:02:51 -0700
Local: Thurs, May 31 2012 1:02 pm
Subject: Drilling plexiglass
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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
chaniarts  
View profile  
 More options May 31 2012, 1:04 pm
Newsgroups: rec.woodworking
From: chaniarts <chania...@nospam.yahoo.com>
Date: Thu, 31 May 2012 10:04:28 -0700
Local: Thurs, May 31 2012 1:04 pm
Subject: Re: Drilling plexiglass
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.

 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
tiredofspam  
View profile  
 More options May 31 2012, 1:13 pm
Newsgroups: rec.woodworking
From: tiredofspam <nospam.nospam.com>
Date: Thu, 31 May 2012 13:13:36 -0400
Local: Thurs, May 31 2012 1:13 pm
Subject: Re: Drilling plexiglass
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:


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
-MIKE-  
View profile  
 More options May 31 2012, 1:20 pm
Newsgroups: rec.woodworking
From: -MIKE- <m...@mikedrumsDOT.com>
Date: Thu, 31 May 2012 12:20:03 -0500
Local: Thurs, May 31 2012 1:20 pm
Subject: Re: Drilling plexiglass
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
  m...@mikedrumsDOT.com
  ---remove "DOT" ^^^^ to reply


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
-MIKE-  
View profile  
 More options May 31 2012, 1:22 pm
Newsgroups: rec.woodworking
From: -MIKE- <m...@mikedrumsDOT.com>
Date: Thu, 31 May 2012 12:22:47 -0500
Local: Thurs, May 31 2012 1:22 pm
Subject: Re: Drilling plexiglass
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
  m...@mikedrumsDOT.com
  ---remove "DOT" ^^^^ to reply


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
bw  
View profile  
 More options May 31 2012, 1:51 pm
Newsgroups: rec.woodworking
From: "bw" <bweg...@hotmail.com>
Date: Thu, 31 May 2012 12:51:17 -0500
Local: Thurs, May 31 2012 1:51 pm
Subject: Re: Drilling plexiglass

"Steve B" <ste...@gmail.com> wrote in message

news:jq887i$i5t$1@speranza.aioe.org...

>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/Plexiglass_Lexan_Plastic_Drill_Bits

 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Jim Weisgram  
View profile  
 More options May 31 2012, 2:16 pm
Newsgroups: rec.woodworking
From: Jim Weisgram <jweisg...@remove2reply.hotmail.com>
Date: Thu, 31 May 2012 11:16:49 -0700
Local: Thurs, May 31 2012 2:16 pm
Subject: Re: Drilling plexiglass
On Thu, 31 May 2012 10:02:51 -0700, "Steve B" <ste...@gmail.com>
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-20&index=blended&link_cod...


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
routerman  
View profile  
 More options May 31 2012, 2:38 pm
Newsgroups: rec.woodworking
From: routerman <p...@patwarner.com>
Date: Thu, 31 May 2012 11:38:53 -0700 (PDT)
Local: Thurs, May 31 2012 2:38 pm
Subject: Re: Drilling plexiglass
Plexipoint (second up from left: http://patwarner.com/drilling_tools.html
)
with negative rake (HSS) about the best for small holes in AC.
No breakage, clean entry & exits. Don't drill at 10000, however.
They stop working @~1/2" diameter, so if you need a bigger hole then
you need another drill.
118 degree tools will work but demand a backup, slow speed (<250) and
sharpness.
Hi feed rate will bust the plastic. Brad point, Forstner, hole saw?
Rediculous.
(That should start a BM storm)
*********************************************
On May 31, 10:02 am, "Steve B" <ste...@gmail.com> wrote:


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Lee Michaels  
View profile  
 More options May 31 2012, 2:47 pm
Newsgroups: rec.woodworking
From: "Lee Michaels" <leemichaels*nadaspam* at comcast dot net>
Date: Thu, 31 May 2012 14:47:50 -0400
Local: Thurs, May 31 2012 2:47 pm
Subject: Re: Drilling plexiglass

> 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.


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Swingman  
View profile  
 More options May 31 2012, 4:25 pm
Newsgroups: rec.woodworking
From: Swingman <k...@nospam.com>
Date: Thu, 31 May 2012 15:25:56 -0500
Local: Thurs, May 31 2012 4:25 pm
Subject: Re: Drilling plexiglass
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/111355467778981859077/EWoodShopBacklitGl...

(cell phone photos, sorry)

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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Leon  
View profile  
 More options May 31 2012, 4:38 pm
Newsgroups: rec.woodworking
From: Leon <lcb11211@swbelldotnet>
Date: Thu, 31 May 2012 15:38:00 -0500
Subject: Re: Drilling plexiglass
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.

 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Lew Hodgett  
View profile  
 More options May 31 2012, 5:14 pm
Newsgroups: rec.woodworking
From: "Lew Hodgett" <sails.m...@verizon.net>
Date: Thu, 31 May 2012 14:14:32 -0700
Local: Thurs, May 31 2012 5:14 pm
Subject: Re: Drilling plexiglass

 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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Larry Blanchard  
View profile  
 More options May 31 2012, 7:25 pm
Newsgroups: rec.woodworking
From: Larry Blanchard <lbla...@fastmail.fm>
Date: Thu, 31 May 2012 23:25:53 +0000 (UTC)
Local: Thurs, May 31 2012 7:25 pm
Subject: Re: Drilling plexiglass

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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Larry Jaques  
View profile  
 More options May 31 2012, 10:01 pm
Newsgroups: rec.woodworking
From: Larry Jaques <ljaq...@invalid.diversifycomm.com>
Date: Thu, 31 May 2012 19:01:53 -0700
Local: Thurs, May 31 2012 10:01 pm
Subject: Re: Drilling plexiglass
On Thu, 31 May 2012 10:04:28 -0700, chaniarts

<chania...@nospam.yahoo.com> 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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Martin Eastburn  
View profile  
 More options May 31 2012, 10:51 pm
Newsgroups: rec.woodworking
From: Martin Eastburn <lionsl...@consolidated.net>
Date: Thu, 31 May 2012 21:51:58 -0500
Local: Thurs, May 31 2012 10:51 pm
Subject: Re: Drilling plexiglass
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:


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Larry Jaques  
View profile  
 More options May 31 2012, 10:58 pm
Newsgroups: rec.woodworking
From: Larry Jaques <ljaq...@invalid.diversifycomm.com>
Date: Thu, 31 May 2012 19:58:15 -0700
Local: Thurs, May 31 2012 10:58 pm
Subject: Re: Drilling plexiglass
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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
m II  
View profile  
 More options Jun 1 2012, 3:17 pm
Newsgroups: rec.woodworking
From: "m II" <C...@in.the.hat>
Date: Fri, 1 Jun 2012 15:17:15 -0400
Local: Fri, Jun 1 2012 3:17 pm
Subject: Re: Drilling plexiglass
Let's destroy his question so we can give answers he didn't ask for.
Here is his text that was conveniently removed from the OP quote.

"Steve B" wrote in message news:jq887i$i5t$1@speranza.aioe.org...

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."

-------------------

"Swingman"  wrote in message

news:qKudnUdcK6dITlrSnZ2dnUVZ_vadnZ2d@giganews.com...

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

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/111355467778981859077/EWoodShopBacklitGl...

(cell phone photos, sorry)

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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Morgans  
View profile  
 More options Jun 2 2012, 9:28 pm
Newsgroups: rec.woodworking
From: "Morgans" <jsmor...@charter.net>
Date: Sat, 2 Jun 2012 21:28:32 -0400
Local: Sat, Jun 2 2012 9:28 pm
Subject: Re: Drilling plexiglass

"Steve B"  wrote in message news:jq887i$i5t$1@speranza.aioe.org...

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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
CW  
View profile  
 More options Jun 3 2012, 1:38 am
Newsgroups: rec.woodworking
From: "CW" <cmag...@earthlink.et>
Date: Sat, 2 Jun 2012 22:38:41 -0700
Local: Sun, Jun 3 2012 1:38 am
Subject: Re: Drilling plexiglass

"Morgans"  wrote in message news:jqeejr$sdd$1@speranza.aioe.org...
"Steve B"  wrote in message news:jq887i$i5t$1@speranza.aioe.org...

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.


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Twayne  
View profile  
 More options Jun 3 2012, 11:05 am
Newsgroups: rec.woodworking
From: "Twayne" <nob...@devnull.spamcop.net>
Date: Sun, 3 Jun 2012 11:05:11 -0400
Local: Sun, Jun 3 2012 11:05 am
Subject: Re: Drilling plexiglass
In news:jqeejr$sdd$1@speranza.aioe.org,
Morgans <jsmor...@charter.net> typed:

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.


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
CW  
View profile  
 More options Jun 3 2012, 2:10 pm
Newsgroups: rec.woodworking
From: "CW" <cmag...@earthlink.et>
Date: Sun, 3 Jun 2012 11:10:15 -0700
Local: Sun, Jun 3 2012 2:10 pm
Subject: Re: Drilling plexiglass

"Twayne"  wrote in message news:jqfufb$90a$2@speranza.aioe.org...

In news:jqeejr$sdd$1@speranza.aioe.org,
Morgans <jsmor...@charter.net> typed:

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

 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Ken Moffett  
View profile  
 More options Jun 3 2012, 4:24 pm
Newsgroups: rec.woodworking
From: Ken Moffett <KLMoff...@comcast.net>
Date: 03 Jun 2012 20:24:13 GMT
Local: Sun, Jun 3 2012 4:24 pm
Subject: Re: Drilling plexiglass
"CW" <cmag...@earthlink.et> wrote in
news:sKadnWxWzsv6ZVfSnZ2dnUVZ_uGdnZ2d@earthlink.com:

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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Martin Eastburn  
View profile  
 More options Jun 5 2012, 11:56 pm
Newsgroups: rec.woodworking
From: Martin Eastburn <lionsl...@consolidated.net>
Date: Tue, 05 Jun 2012 22:56:06 -0500
Local: Tues, Jun 5 2012 11:56 pm
Subject: Re: Drilling plexiglass
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:


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Doug White  
View profile  
 More options Jun 6 2012, 5:54 pm
Newsgroups: rec.woodworking
From: Doug White <gwh...@alum.mit.edu>
Date: Wed, 06 Jun 2012 21:54:08 GMT
Local: Wed, Jun 6 2012 5:54 pm
Subject: Re: Drilling plexiglass
Martin Eastburn <lionsl...@consolidated.net> wrote in
news:qxAzr.130924$eR7.75563@en-nntp-16.dc1.easynews.com:

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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
routerman  
View profile  
 More options Jun 6 2012, 6:17 pm
Newsgroups: rec.woodworking
From: routerman <p...@patwarner.com>
Date: Wed, 6 Jun 2012 15:17:30 -0700 (PDT)
Local: Wed, Jun 6 2012 6:17 pm
Subject: Re: Drilling plexiglass

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


 
You must Sign in before you can post messages.
To post a message you must first join this group.
Please update your nickname on the subscription settings page before posting.
You do not have the permission required to post.
Messages 1 - 25 of 29   Newer >
« Back to Discussions « Newer topic     Older topic »