tip of the month #7

F

Frank Bemelman

Guest
Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
suddenly grips, or it climbs up in the drill, or giving
that sort of hexagon shaped hole you didn't want.

This morning I discovered a new method. Drill a small
hole of 3 mm. This goes without problems.

Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)
 
"Frank Bemelman" wrote:

Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
suddenly grips, or it climbs up in the drill, or giving
that sort of hexagon shaped hole you didn't want.

This morning I discovered a new method. Drill a small
hole of 3 mm. This goes without problems.

Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.
Click to expand...
And cutting square or rectangular holes is even more difficult.

I use a dremmel router table with home made wooden templates. You have to make
the template for each case and each hole but for very small production runs
it's ideal.

You basically make a cage on the template, put the case in it, and move it
round in ever increasing squares until it's running right round inside the
template. Perfect hole every time.

I suppose for many different "one offs" a multi purpose template could be made
with movable pieces.

Gibbo
 
Frank Bemelman wrote:
Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
suddenly grips, or it climbs up in the drill, or giving
that sort of hexagon shaped hole you didn't want.

This morning I discovered a new method. Drill a small
hole of 3 mm. This goes without problems.

Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.
Click to expand...
Me, I just use a step drill.

Cheers
Terry
 
Frank Bemelman wrote:
Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
suddenly grips, or it climbs up in the drill, or giving
that sort of hexagon shaped hole you didn't want.

This morning I discovered a new method. Drill a small
hole of 3 mm. This goes without problems.

Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.
Click to expand...
The standard (as I know it) procedure is to blunt the
high-diameter drills. Basically increasing the angle
of the two cutting edges to 90deg. You still need a pilot
hole.

Funny that your holes are hexagonal. My ones tend to get
pentagonal. I assumed it has something to do with edge
length to radius ratio of the HSS drills.

Regards,

Iwo
 
On Fri, 22 Oct 2004 14:55:14 +0100, Iwo Mergler wrote:

Frank Bemelman wrote:
Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
suddenly grips, or it climbs up in the drill, or giving
that sort of hexagon shaped hole you didn't want.

This morning I discovered a new method. Drill a small
hole of 3 mm. This goes without problems.

Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.


The standard (as I know it) procedure is to blunt the
high-diameter drills. Basically increasing the angle
of the two cutting edges to 90deg. You still need a pilot
hole.

Funny that your holes are hexagonal. My ones tend to get
pentagonal. I assumed it has something to do with edge
length to radius ratio of the HSS drills.

Some guy once saw me drilling some sheet aluminum, and remarked
Click to expand...
that "you're going to get a three-sided hole", which I did, and
so mine have been triangular ever since. :)

Cheers!
Rich
 
On Fri, 22 Oct 2004 11:00:28 +0200, "Frank Bemelman"
<f.bemelmanx@xs4all.invalid.nl> wrote:

Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
suddenly grips, or it climbs up in the drill, or giving
that sort of hexagon shaped hole you didn't want.

This morning I discovered a new method. Drill a small
hole of 3 mm. This goes without problems.

Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.
Click to expand...
I have a whole set of bits that are for sheet metal (Black and Decker
"Bullet" brand) with cutter "wings" on the edges... works just ducky
for plastic, just don't go too fast or you get "pile-up".

I've had reasonable success with wood bits for larger holes, though I
still do own a considerable set of chassis punches from my toooobz
days ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On Fri, 22 Oct 2004 17:38:32 GMT, the renowned Rich Grise
<rich@example.net> wrote:
Some guy once saw me drilling some sheet aluminum, and remarked
that "you're going to get a three-sided hole", which I did, and
so mine have been triangular ever since. :)

Cheers!
Rich
Click to expand...
Clamp everything down really well and drill into sacrificial material
and you'll get a nice hole even with an aggressive twist drill. I like
center/centre drills for medium-size holes in plastic.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
"Jim Thompson" <thegreatone@example.com> schreef in bericht
news:uihin0d8dupsr1sg0v3h9vmb4rfihke6s1@4ax.com...
On Fri, 22 Oct 2004 11:00:28 +0200, "Frank Bemelman"
f.bemelmanx@xs4all.invalid.nl> wrote:

Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
suddenly grips, or it climbs up in the drill, or giving
that sort of hexagon shaped hole you didn't want.

This morning I discovered a new method. Drill a small
hole of 3 mm. This goes without problems.

Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.

I have a whole set of bits that are for sheet metal (Black and Decker
"Bullet" brand) with cutter "wings" on the edges... works just ducky
for plastic, just don't go too fast or you get "pile-up".

I've had reasonable success with wood bits for larger holes, though I
still do own a considerable set of chassis punches from my toooobz
days ;-)
Click to expand...
Those punches are worth gold. I have a couple, even a few for square
holes. First you drill a round hole for the bolt/nut of course. My
father 'stole' them from Fokker Aircraft just before he retired ;)

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)
 
"Frank Bemelman" <f.bemelmanx@xs4all.invalid.nl> wrote in message
news:4178cbe5$0$65124$e4fe514c@news.xs4all.nl...
Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
suddenly grips, or it climbs up in the drill, or giving
that sort of hexagon shaped hole you didn't want.

This morning I discovered a new method. Drill a small
hole of 3 mm. This goes without problems.

Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.
Click to expand...
I use a taper drill. Works very well for plastic and thin metal.

Leon
 
"Leon Heller" <leon_heller@hotmail.com> schreef in bericht
news:41796940$0$24201$cc9e4d1f@news-text.dial.pipex.com...
"Frank Bemelman" <f.bemelmanx@xs4all.invalid.nl> wrote in message
news:4178cbe5$0$65124$e4fe514c@news.xs4all.nl...
Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
suddenly grips, or it climbs up in the drill, or giving
that sort of hexagon shaped hole you didn't want.

This morning I discovered a new method. Drill a small
hole of 3 mm. This goes without problems.

Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.

I use a taper drill. Works very well for plastic and thin metal.
Click to expand...
You have to know when to stop, with tapered drills. And I often
manage to ruin them quickly, in metal. Terry mentioned step drills,
I have one, but with rather large steps. I had to drill 25 boxes,
a very unusual event for me. Kept me busy for the whole day,
almost. I guess the best method is to let someone else drill
them ;)


--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)
 
On Fri, 22 Oct 2004 23:16:07 +0200, Frank Bemelman wrote:
"Leon Heller" <leon_heller@hotmail.com> schreef in bericht
"Frank Bemelman" <f.bemelmanx@xs4all.invalid.nl> wrote in message
Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
....
Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.

I use a taper drill. Works very well for plastic and thin metal.

You have to know when to stop, with tapered drills. And I often
manage to ruin them quickly, in metal. Terry mentioned step drills,
I have one, but with rather large steps. I had to drill 25 boxes,
a very unusual event for me. Kept me busy for the whole day,
almost. I guess the best method is to let someone else drill
them ;)
Click to expand...
For 25, I might have gone looking for a punch of some kind. :)

Cheers!
Rich
 
On Fri, 22 Oct 2004 21:23:01 GMT, the renowned Rich Grise
<rich@example.net> wrote:

On Fri, 22 Oct 2004 23:16:07 +0200, Frank Bemelman wrote:
"Leon Heller" <leon_heller@hotmail.com> schreef in bericht
"Frank Bemelman" <f.bemelmanx@xs4all.invalid.nl> wrote in message
Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
...
Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.

I use a taper drill. Works very well for plastic and thin metal.

You have to know when to stop, with tapered drills. And I often
manage to ruin them quickly, in metal. Terry mentioned step drills,
I have one, but with rather large steps. I had to drill 25 boxes,
a very unusual event for me. Kept me busy for the whole day,
almost. I guess the best method is to let someone else drill
them ;)
Click to expand...
The case suppliers will often do that for a relatively reasonable
price, at least compared to engineers fiddling around with it. If
you've got access to minimum-wage labor, that's another situation.

For 25, I might have gone looking for a punch of some kind. :)

Cheers!
Rich
Click to expand...
Punches are nice, clean and fast (once setup), but there are sometimes
problems if the part being punched isn't essentially flat.
 
On Fri, 22 Oct 2004 20:41:52 +0200, "Frank Bemelman"
<f.bemelmanx@xs4all.invalid.nl> wrote:


Hexagonal is a sort of pentagonal ;)
Click to expand...
---
Some times it's hard to tell which is witch?

--
John Fields
 
You forgot to tell them to hold the object firmly between their legs.

"Frank Bemelman" <f.bemelmanx@xs4all.invalid.nl> wrote in message
news:4178cbe5$0$65124$e4fe514c@news.xs4all.nl...
Drilling large holes in plastic cases is always great
fun. Either the workpiece gets launched when the drill
suddenly grips, or it climbs up in the drill, or giving
that sort of hexagon shaped hole you didn't want.

This morning I discovered a new method. Drill a small
hole of 3 mm. This goes without problems.

Now take a *wood* drill, a round one, not the speed type,
although that may work too. Put the drill in reverse.
Drill the hole. Enjoy the result. Say 'Eureka'.

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)
Click to expand...
 
On Fri, 22 Oct 2004 06:11:09 -0500, "Jim Douglas"
<james.douglas@genesis-software.com> wrote:

You forgot to tell them to hold the object firmly between their legs.

[snip]
Click to expand...

I used to do that.

Then, one day the drill bit popped thru the work and into my pants
leg, just below the family jewels, twisting the pants tight like a
tourniquet before I could let loose of the switch.

Fortunately didn't even nick the skin.

I went out and bought several sizes of vises ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On Fri, 22 Oct 2004 17:56:53 -0400, Spehro Pefhany wrote:

On Fri, 22 Oct 2004 21:23:01 GMT, the renowned Rich Grise
rich@example.net> wrote:

On Fri, 22 Oct 2004 23:16:07 +0200, Frank Bemelman wrote:
"Leon Heller" <leon_heller@hotmail.com> schreef in bericht
"Frank Bemelman" <f.bemelmanx@xs4all.invalid.nl> wrote in message
Drilling large holes in plastic cases is always great fun. Either
the workpiece gets launched when the drill
...
Now take a *wood* drill, a round one, not the speed type, although
that may work too. Put the drill in reverse. Drill the hole. Enjoy
the result. Say 'Eureka'.

I use a taper drill. Works very well for plastic and thin metal.

You have to know when to stop, with tapered drills. And I often manage
to ruin them quickly, in metal. Terry mentioned step drills, I have
one, but with rather large steps. I had to drill 25 boxes, a very
unusual event for me. Kept me busy for the whole day, almost. I guess
the best method is to let someone else drill them ;)

The case suppliers will often do that for a relatively reasonable price,
at least compared to engineers fiddling around with it. If you've got
access to minimum-wage labor, that's another situation.

For 25, I might have gone looking for a punch of some kind. :)

Cheers!
Rich

Punches are nice, clean and fast (once setup), but there are sometimes
problems if the part being punched isn't essentially flat.
Click to expand...
And even while writing that, all I could think of is trying to
whack an arch punch through polystyrene. Hah!

Cheers!
Rich
 
On Fri, 22 Oct 2004 17:57:16 -0700, Jim Thompson <thegreatone@example.com>
wrote:

On Fri, 22 Oct 2004 06:11:09 -0500, "Jim Douglas"
james.douglas@genesis-software.com> wrote:

You forgot to tell them to hold the object firmly between their legs.

[snip]

I used to do that.

Then, one day the drill bit popped thru the work and into my pants
leg, just below the family jewels, twisting the pants tight like a
tourniquet before I could let loose of the switch.

Fortunately didn't even nick the skin.
Click to expand...
I suspect that if most readers of this group were to 'fess up, you'd find we
nearly all did something frighteningly similar back when we were younger ..
 
"Frank Bemelman" <f.bemelmanx@xs4all.invalid.nl> wrote:

You have to know when to stop, with tapered drills. And I often
manage to ruin them quickly, in metal. Terry mentioned step drills,
I have one, but with rather large steps. I had to drill 25 boxes,
a very unusual event for me. Kept me busy for the whole day,
almost. I guess the best method is to let someone else drill
them ;)
Click to expand...
A little bit of oil should be used when drilling metal.

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl
 
Frank Bemelman <f.bemelmanx@xs4all.invalid.nl> wrote:
<snip>
If faced with two wires of the same colour that you're making into a loose
hookup.
Tie a knot in one wire at each end.
For DC, knot=naught=0V.
 
On 23 Oct 2004 15:45:34 GMT, Ian Stirling <root@mauve.demon.co.uk>
wrote:

Frank Bemelman <f.bemelmanx@xs4all.invalid.nl> wrote:
snip
If faced with two wires of the same colour that you're making into a loose
hookup.
Tie a knot in one wire at each end.
For DC, knot=naught=0V.
Click to expand...
---
I've always used "knot=hot".

--
John Fields
 
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