27 Oct
2015
27 Oct
'15
3:05 a.m.
Hi Guys
I need to get some comments on the following.
1. Would a matt finish be better than the current glossy one?
2. Should the round holes be pre-drilled?
Regards
Rod
27 Oct
27 Oct
3:20 a.m.
On Mon, Oct 26, 2015 at 11:05 PM, rod <rodsmallwood52 at btinternet.com> wrote:
Hi Guys
I need to get some comments on the following.
1. Would a matt finish be better than the current glossy one?
Hard to say, but generally, I think a closer match to the original is
better. Is there a reason you want to consider a different finish?
Cost? Fingerprints?
2. Should the round holes be pre-drilled?
I would think that the fewer holes that the users have to make in a
brittle substance like acrylic, the better. It's easy to crack with a
twist-drill, which is what most people have. There are "right ways"
to drill it, but it's not wood. Lasers do a nice job of making smooth
holes in acrylic.
-ethan
3:28 a.m.
On 10/26/2015 8:05 PM, rod wrote:
Hi Guys
I need to get some comments on the following.
1. Would a matt finish be better than the current glossy one?
2. Should the round holes be pre-drilled?
Regards
Rod
I would prefer the holes be drilled. It's not easy to drill the plastic
as I found out, with small chips around the edges.
And that was with a bit made for plastic.
Bob
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3:54 a.m.
To effectively drill in plastics you need to run the drill press on the
highest speed you can
and use a freshly sharpened drill bit.
It kinda melts its way through.
On 10/26/2015 8:28 PM, Bob Rosenbloom wrote:
On 10/26/2015 8:05 PM, rod wrote:
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Hi Guys
I need to get some comments on the following.
1. Would a matt finish be better than the current glossy one?
2. Should the round holes be pre-drilled?
Regards
Rod
I would prefer the holes be drilled. It's not easy to drill the
plastic as I found out, with small chips around the edges.
And that was with a bit made for plastic.
Bob
4:38 a.m.
On 10/26/2015 08:54 PM, wulfman wrote:
To effectively drill in plastics you need to run the
drill press on
the highest speed you can and use a freshly sharpened drill bit.
If this is Perspex/Plexiglas, I've had great results with a good sharp
Forstner bit in my drill press at medium (say 750 RPM) speed and a
not-too aggressive feed.. No melting, just lots of crumbly shavings.
I've done this with sizes down to about 1/4", but no smaller. When
you're almost through the material, turn it over and complete the hole
from the back side. Very clean edges, with no chips
at all.
--Chuck
6:59 a.m.
On 10/26/2015 08:54 PM, wulfman wrote:
Agree with Chuck, a moderate drilling speed is better, you do _not_ want
to melt your way through, you want to cut.
And my advice, sadly learnt and forgotten quite a few times, always after
drilling a critical part:
**** CLAMP THE JOB DOWN! ****
If you think you can hold the Perspex with your fingers, you can't and
your nice panel piece suddenly catches, climbs up the drill bit in a flash
and is wrecked before you can say something nice like 'Oh golly I do wish
I had clamped it down!' or words (not) to that effect.
For clamps I suggest those newfangled ratchet clamps. I bought some a few years
ago and they are the best thing ever. These things ar esuperior to the
average old-fashioned G-clamp in almost every way, except for when massive
pressure is required. (search 'crescent connect clamp' on eBay, the 12"
ones
are excellent). And like G-clamps, you can never have enough of these, get
some different sizes.
Steve.
To effectively drill in plastics you need to run
the drill press on
the highest speed you can and use a freshly sharpened drill bit.
If this is Perspex/Plexiglas, I've had great results with a good sharp
Forstner bit in my drill press at medium (say 750 RPM) speed and a
not-too aggressive feed.. No melting, just lots of crumbly shavings.
I've done this with sizes down to about 1/4", but no smaller. When
you're almost through the material, turn it over and complete the hole
from the back side. Very clean edges, with no chips at all.
--Chuck
9:08 a.m.
Hi
Yes clamp it down. I have a pillar drill and that has a table that
the workpiece can be clamped to.
This means they are at right angles to each other. So the drill bit
works as designed.
Sharpen or replace drill bits if they get worn.
Next start small and work up in drill size. There are tables for speed,
feed, size of drill and type of material.
As my old school metalwork master would say "more speed less feed".
Whilst you may not be able to judge feed rate because it involves time.
Slower feed is better.
Rod
On 27/10/15 06:59, steven at malikoff.com wrote:
On 10/26/2015
08:54 PM, wulfman wrote:
Agree with Chuck, a moderate drilling speed is better, you do _not_ want
to melt your way through, you want to cut.
And my advice, sadly learnt and forgotten quite a few times, always after
drilling a critical part:
**** CLAMP THE JOB DOWN! ****
If you think you can hold the Perspex with your fingers, you can't and
your nice panel piece suddenly catches, climbs up the drill bit in a flash
and is wrecked before you can say something nice like 'Oh golly I do wish
I had clamped it down!' or words (not) to that effect.
For clamps I suggest those newfangled ratchet clamps. I bought some a few years
ago and they are the best thing ever. These things ar esuperior to the
average old-fashioned G-clamp in almost every way, except for when massive
pressure is required. (search 'crescent connect clamp' on eBay, the 12"
ones
are excellent). And like G-clamps, you can never have enough of these, get
some different sizes.
Steve.
To effectively drill in plastics you need to run
the drill press on
the highest speed you can and use a freshly sharpened drill bit.
If this is
Perspex/Plexiglas, I've had great results with a good sharp
Forstner bit in my drill press at medium (say 750 RPM) speed and a
not-too aggressive feed.. No melting, just lots of crumbly shavings.
I've done this with sizes down to about 1/4", but no smaller. When
you're almost through the material, turn it over and complete the hole
from the back side. Very clean edges, with no chips at all.
--Chuck 
10:27 a.m.
On 27 Oct 2015, at 5:59 PM, steven at malikoff.com
wrote:
And my advice, sadly learnt and forgotten quite a few times, always after
drilling a critical part:
**** CLAMP THE JOB DOWN! ****
+1 on Steven's advice, having
learned this lesson the hard-way.
12:58 p.m.
And my advice,
sadly learnt and forgotten quite a few times, always after
drilling a critical part:
**** CLAMP THE JOB DOWN! ****
+1 on Steven's advice, having
learned this lesson the hard-way. 
12:12 p.m.
There are special bits for plastics, and they work quite well. Regular
bits are troublesome on most plastics.
--
Will
On Tue, Oct 27, 2015 at 12:38 AM, Chuck Guzis <cclist at sydex.com> wrote:
On 10/26/2015 08:54 PM, wulfman wrote:
To effectively drill in plastics you need to run the drill press on
the highest speed you can and use a freshly sharpened drill bit.
If this is Perspex/Plexiglas, I've had great results with a good sharp
Forstner bit in my drill press at medium (say 750 RPM) speed and a not-too
aggressive feed.. No melting, just lots of crumbly shavings. I've done this
with sizes down to about 1/4", but no smaller. When you're almost through
the material, turn it over and complete the hole from the back side. Very
clean edges, with no chips at all.
--Chuck
4:33 p.m.
On 10/26/2015 11:38 PM, Chuck Guzis wrote:
On 10/26/2015 08:54 PM, wulfman wrote:
The ultimate way to drill holes in Plexi is with an end
mill. It can make a slight chipping when it punches through
the back, so you either need a backstop material or lighten
up the feed a bit just before it goes through. (This of
course requires a center-cutting end mill, I prefer 4-flute
for this.)
Even better than just plunging an end mill is to use a CNC
mill and a cutter smaller than the required hole diameter.
You use a pocket boring routine, set up for "climb milling"
and after working through the material in several depth
steps just less then the desired diameter, does a finish
pass at full depth to bring it to final hole size. This
takes longer to describe than it actually takes the machine
to perform, and leaves beautiful holes.
Jon
To effectively drill in plastics you need to run
the
drill press on
the highest speed you can and use a freshly sharpened
drill bit.
If this is Perspex/Plexiglas, I've had great results with
a good sharp Forstner bit in my drill press at medium (say
750 RPM) speed and a not-too aggressive feed.. No
melting, just lots of crumbly shavings. I've done this
with sizes down to about 1/4", but no smaller. When
you're almost through the material, turn it over and
complete the hole from the back side. Very clean edges,
with no chips at all
4:59 p.m.
On 10/27/2015 09:33 AM, Jon Elson wrote:
The ultimate way to drill holes in Plexi is with an
end mill. It can
make a slight chipping when it punches through the back, so you
either need a backstop material or lighten up the feed a bit just
before it goes through. (This of course requires a center-cutting
end mill, I prefer 4-flute for this.)
Sure, but I'm assuming that the original poster doesn't have a
Bridgeport mill at his disposal. But a drill press is quite within the
budget of most hobbyists. I'd think that if you already owned a
vertical mill, you'd know how to work with plastics.
Back in the day, I loved hanging out at the model shop just watching the
action and trying to second-guess the guys there. Building a case with
curves such as side contoured to a 200 inch radius was serious business.
The finished product was in clear acrylic, all ready to go to the mold
makers.
Similarly, making the die set for punching sector holes in a 8" floppy
would be child's play for someone with a wire EDM rig in his garage.
But not every hobbyist can afford one.
--Chuck
5:52 p.m.
On 10/27/2015 11:59 AM, Chuck Guzis wrote:
On 10/27/2015 09:33 AM, Jon Elson wrote:
You CAN use an end mill in a drill press if you are
careful. You get no self-centering, so the work must be
**SECURELY** clamped, as the cutter may try to walk. But,
you'll get perfectly round, smooth holes.
Twist drills tend to wander and make triangular and slightly
helical holes.
Obviously, you can only do this with small size end mills in
a drill press.
Jon
The ultimate way to drill holes in Plexi is with
an end
mill. It can
make a slight chipping when it punches through the back,
so you
either need a backstop material or lighten up the feed a
bit just
before it goes through. (This of course requires a
center-cutting
end mill, I prefer 4-flute for this.)
Sure, but I'm assuming that the original poster doesn't
have a Bridgeport mill at his disposal. But a drill press
is quite within the budget of most hobbyists. I'd think
that if you already owned a vertical mill, you'd know how
to work with plastics.
6:05 p.m.
On 10/27/2015 10:52 AM, Jon Elson wrote:
You CAN use an end mill in a drill press if you are
careful. You get
no self-centering, so the work must be **SECURELY** clamped, as the
cutter may try to walk. But, you'll get perfectly round, smooth
holes. Twist drills tend to wander and make triangular and slightly
helical holes.
Obviously, you can only do this with small size end mills in a drill
press.
A good sharp forstner bit, by its very construction guarantees perfectly
round holes--and it's not self-feeding, so you can cut as slowly as
you'd like.
Awhile back, I made a tape lubrication jig consisting of several pieces
of 5/8" OD brass tube with small holes drilled (think #70 drill) mounted
in 3/8" acrylic with a second 3/8" piece to form a bottom. Absolutely
water-tight fit with no adhesives--the tube was simply press-fitted into
the round holes. The bottom was attached to the upper piece using
stainless 4-40 machine screws. It worked fairly well.
--Chuck
5:07 p.m.
On Oct 27, 2015, at 12:33 PM, Jon Elson <elson at
pico-systems.com> wrote:
On 10/26/2015 11:38 PM, Chuck Guzis wrote:
I would think a counterbore would work better, because it doesn't cut on the sides,
only on the bottom.
paul
On 10/26/2015 08:54 PM, wulfman wrote:
The
ultimate way to drill holes in Plexi is with an end mill. It can make a slight chipping
when it punches through the back, so you either need a backstop material or lighten up the
feed a bit just before it goes through. (This of course requires a center-cutting end
mill, I prefer 4-flute for this.) To effectively drill in plastics you need to run
the drill press on
the highest speed you can and use a freshly sharpened drill bit.
If this is Perspex/Plexiglas, I've had great results with a good sharp Forstner bit
in my drill press at medium (say 750 RPM) speed and a not-too aggressive feed.. No
melting, just lots of crumbly shavings. I've done this with sizes down to about
1/4", but no smaller. When you're almost through the material, turn it over and
complete the hole from the back side. Very clean edges, with no chips at all
6:45 p.m.
OK Here's my two cents worth.
First put tape across the area.
Make sure it wont take the silk screen printing off.
Get a small drill. A 1mm PCB drill is a good choice.
Drill through with the drill set to a fast but not too fast speed.
Turn the work over and re-clamp it. open up the hole but don't drill
right through,
Turn back to the side you started with and drill right through.
Rod
On 27/10/15 16:33, Jon Elson wrote:
On 10/26/2015 11:38 PM, Chuck Guzis wrote:
On 10/26/2015 08:54 PM, wulfman wrote:
The ultimate way to drill holes in Plexi is with an end mill. It can
make a slight chipping when it punches through the back, so you either
need a backstop material or lighten up the feed a bit just before it
goes through. (This of course requires a center-cutting end mill, I
prefer 4-flute for this.)
Even better than just plunging an end mill is to use a CNC mill and a
cutter smaller than the required hole diameter.
You use a pocket boring routine, set up for "climb milling" and after
working through the material in several depth steps just less then the
desired diameter, does a finish pass at full depth to bring it to
final hole size. This takes longer to describe than it actually takes
the machine to perform, and leaves beautiful holes.
Jon To effectively drill in plastics you need to run
the drill press on
the highest speed you can and use a freshly sharpened drill bit.
If this is Perspex/Plexiglas, I've had great results with a good
sharp Forstner bit in my drill press at medium (say 750 RPM) speed
and a not-too aggressive feed.. No melting, just lots of crumbly
shavings. I've done this with sizes down to about 1/4", but no
smaller. When you're almost through the material, turn it over and
complete the hole from the back side. Very clean edges, with no
chips at all
3128
days inactive
3128
days old
15 comments
11 participants
participants (11)
-
ard＠p850ug1.demon.co.uk -
bobalan＠sbcglobal.net -
cclist＠sydex.com -
elson＠pico-systems.com -
ethan.dicks＠gmail.com -
nw＠retrocomputingtasmania.com -
paulkoning＠comcast.net -
rodsmallwood52＠btinternet.com -
steven＠malikoff.com -
wdonzelli＠gmail.com -
wulfman＠wulfman.com