Can somebody give me some advice here?

I have two left hands and I need to drill a 12cm
diameter hole in a steel plate about 1mm thick
(the top cover of a computer case).

The top of the case has black enamel laquer and
it would be nice if I could do it with minimum
damage to that and as neatly as possible.

What would the experts do here, and what tools
do I need? Are there maybe even places that do
things like that for you for a small fee?

TIA, David

David Johnstone wrote:
Can somebody give me some advice here?

I have two left hands and I need to drill a 12cm
diameter hole in a steel plate about 1mm thick
(the top cover of a computer case).

The top of the case has black enamel laquer and
it would be nice if I could do it with minimum
damage to that and as neatly as possible.

What would the experts do here, and what tools
do I need? Are there maybe even places that do
things like that for you for a small fee?

TIA, David

clamp the job between 2 bits of ply and drill it with a 12mm drill,
remove plywood, finish off with a rat tail file, job done


RT

[news] wrote:

clamp the job between 2 bits of ply and drill it with a 12mm drill,
remove plywood, finish off with a rat tail file, job done

That'd work fine for a 12 /mm/ hole...

For the OP - a bimetal hole saw will do a pretty good job:
http://www.toolstation.com/index.html?code=56846

You'll get a better finish if you clamp ply both sides as per the above
suggestion.


--
Grunff

"David Johnstone" wrote in message
om...
Can somebody give me some advice here?

I have two left hands and I need to drill a 12cm
diameter hole in a steel plate about 1mm thick
(the top cover of a computer case).

The top of the case has black enamel laquer and
it would be nice if I could do it with minimum
damage to that and as neatly as possible.

What would the experts do here, and what tools
do I need? Are there maybe even places that do
things like that for you for a small fee?

TIA, David

===============
I do mine with a jigsaw with metal cutting blade. I use masking tape to hold
thin card around the cutting area to prevent scratching. If you can't do it
yourself ask your friendly DIY neighbour to do it for you. It's only a 5
minute job and it's really not difficult. Alternatively since you've asked
in a DIY group why not take the plunge and buy your own jigsaw so that
you'll be ready to do the job next time you need to do it?

Cic.

I've never tried a jigsaw (I didn't have one when I was doing most of my
case modding) but I found drilling multiple holes, sawing it roughly
round and then using a large half round metal file to finish off gives a
surprisingly good finish. It's a bit of work, probably more than a using
a jigsaw, I would guess it would take about 2 or 3 hours.

David Johnstone wrote:
Can somebody give me some advice here?

I have two left hands and I need to drill a 12cm
diameter hole in a steel plate about 1mm thick
(the top cover of a computer case).

The top of the case has black enamel laquer and
it would be nice if I could do it with minimum
damage to that and as neatly as possible.

What would the experts do here, and what tools
do I need? Are there maybe even places that do
things like that for you for a small fee?

TIA, David

David Johnstone wrote:
Can somebody give me some advice here?

I have two left hands and I need to drill a 12cm
diameter hole in a steel plate about 1mm thick
(the top cover of a computer case).

A 120mm artillery piece is what you need.
One bang, job done.

"David Johnstone" wrote in message
om...
Can somebody give me some advice here?

I have two left hands and I need to drill a 12cm
diameter hole in a steel plate about 1mm thick
(the top cover of a computer case).


persons of a certain age used to use sheet metal hole cutters for radio
chassis:

http://www.lawson-his.co.uk/scripts/...Hole%20Cutters

but as there aren't any chassis these days they're harder to find.

doozer wrote:
I've never tried a jigsaw (I didn't have one when I was doing most of my
case modding) but I found drilling multiple holes, sawing it roughly
round and then using a large half round metal file to finish off gives a
surprisingly good finish. It's a bit of work, probably more than a using
a jigsaw, I would guess it would take about 2 or 3 hours.

However, it's harder to screw up.
Take a nail and hammer.
Punch the case at the point you want each 10mm (or so) hole.
Drill a 3mm hole.
Repeat with a 10mm drill.
Now, go around the edge with wiresnips, snipping the bits off, then file.
If you use the file in the right way (only press down when it's cutting down
past the varnish, you may not even flake any off.

"David Johnstone" wrote in message
om...
Can somebody give me some advice here?

I have two left hands and I need to drill a 12cm
diameter hole in a steel plate about 1mm thick
(the top cover of a computer case).

When I wanted a fan hole in a case (I was upgrading for a friend and he
wanted to keep the original desktop case, as he had had shelving built
specially to fit it), I used 15" G clamps to hold the case onto a thick
block of wood on the table of a pillar drill. I then cut the hole with a fly
cutter at 300 rpm.

Ear defenders are recommended (it screeches a lot, even with lubrication).
High impact eye protection is essential when using a fly cutter, even at low
speed.

Colin Bignell

In article ,
"Ian Stirling" says...
doozer wrote:
I've never tried a jigsaw (I didn't have one when I was doing most of my
case modding) but I found drilling multiple holes, sawing it roughly
round and then using a large half round metal file to finish off gives a
surprisingly good finish. It's a bit of work, probably more than a using
a jigsaw, I would guess it would take about 2 or 3 hours.

However, it's harder to screw up.
Take a nail and hammer.
Punch the case at the point you want each 10mm (or so) hole.
Drill a 3mm hole.
Repeat with a 10mm drill.
Now, go around the edge with wiresnips, snipping the bits off, then file.
If you use the file in the right way (only press down when it's cutting down
past the varnish, you may not even flake any off.

Why not just use aviation tinsnips?

Grunff wrote:
[news] wrote:

clamp the job between 2 bits of ply and drill it with a 12mm drill,
remove plywood, finish off with a rat tail file, job done

That'd work fine for a 12 /mm/ hole...

ahem..... erm ... Jigsaw, I meant Jigsaw



RT

The normal way of 'drilling' a large hole in such thin plate like this is to use a die, this come in two pieces that are clamped together slowly with a screw thread.

Phone round some sheet metal engineering places to see if they have such a die, if they do they may be able to help. Obviously, the die needs to be the right diameter.

I think most laser cutting places can only work with flat sheet, but its worth a ring round, if they can cut a formed piece, then all they need is a drawing.

The same goes for CNC punches.

If you want to go more DIY, then mark out your hole with a pencil, then drill a series of small holes round it with a good drill bit, do this well inside of the line. Then use a hacksaw blade to join the holes up. Buy what is called a nibbler - you can get air, electric or hand ones, these bite tiny slithers of metal in thin sheet. Use this to get as close to the line as you dare.

Then finish the job carefully with a reasonably fine file.

If you drag the file along the edge as you finish, it will remove any burrs.

If before starting the job you cover the rest of the shell in insulation tape, masking tape or sticky plastic film, you'll prevent any accidental scratches.

That is unless you plan to spray paint it once its complete.

I would argue, though, for the cost of a PC case, can't you get a new one that has the holes in the right place? It would probably cost less than any machining and/or tools.

Regards,
Jason.

In uk.d-i-y, David Johnstone wrote:
I have two left hands and I need to drill a 12cm
diameter hole in a steel plate about 1mm thick
(the top cover of a computer case).

The top of the case has black enamel laquer and
it would be nice if I could do it with minimum
damage to that and as neatly as possible.

What would the experts do here, and what tools
do I need? Are there maybe even places that do
things like that for you for a small fee?

No expert me, but I'd try a nibbler, like this:

http://www.rapidelectronics.co.uk/rk...&CTL_CAT_CODE=
30503&STK_PROD_CODE=M36734&XPAGENO=1

Your steel might be a bit thick, I don't know.

You need to drill a 10mm hole to start with, near the edge of your
eventual hole, but not so close that you risk marking past the edge of
the hole. Cover the area with masking tape first, to protect the surface
and make it easy to draw your guide line on.

You'll find those nibblers handy for cutting all sorts of shapes in
sheet metal and plastic.

--
Mike Barnes

Mike Barnes wrote :-

No expert me, but I'd try a nibbler, like this:

http://www.rapidelectronics.co.uk/rk...&CTL_CAT_CODE=
30503&STK_PROD_CODE=M36734&XPAGENO=1

Your steel might be a bit thick, I don't know.

You need to drill a 10mm hole to start with, near the edge of your
eventual hole, but not so close that you risk marking past the edge of
the hole. Cover the area with masking tape first, to protect the surface
and make it easy to draw your guide line on.

You'll find those nibblers handy for cutting all sorts of shapes in
sheet metal and plastic.

You can also get a power version that fits in an electric drill, got mine
from Machine Mart about £15 iirc, it cuts car body panels so should do pc
cases.

Regards Jeff

Rob Morley wrote:
In article ,
"Ian Stirling" says...
doozer wrote:
I've never tried a jigsaw (I didn't have one when I was doing most of my
case modding) but I found drilling multiple holes, sawing it roughly
snip
Why not just use aviation tinsnips?

I doubt the OP has them.

"Jeff" wrote in message
...

Mike Barnes wrote :-

No expert me, but I'd try a nibbler, like this:

http://www.rapidelectronics.co.uk/rk...&CTL_CAT_CODE=
30503&STK_PROD_CODE=M36734&XPAGENO=1

Your steel might be a bit thick, I don't know.

You need to drill a 10mm hole to start with, near the edge of your
eventual hole, but not so close that you risk marking past the edge of
the hole. Cover the area with masking tape first, to protect the surface
and make it easy to draw your guide line on.

You'll find those nibblers handy for cutting all sorts of shapes in
sheet metal and plastic.

You can also get a power version that fits in an electric drill, got mine
from Machine Mart about £15 iirc, it cuts car body panels so should do pc
cases.

Regards Jeff



Take it to an electrical panel builders and ask them to punch the size of
the hole you require. They have hydraulic punches that will do the job in
'jig' time. They can punch holes up to 3mm in steel, 1.5mm in stainless.
They will probably charge you a nominal amount. Alternatively a commercial
kitchen fabricator would be able to do it for you.

John wrote:

persons of a certain age used to use sheet metal hole cutters for radio
chassis:

For small holes like B7G and B9A yes, but for anything larger I couldn't
afford Q-max punches and used to use my dad's old tank cutter - the type
you used in a hand brace. Slow, but it produced nice neat round holes
requiring a minimum of de-burring.

A quick Google shows that adjustable tank cutters are still available,
so there's another option for the OP (if you can find one that
adjusts-up big enough). Use of the Abrafile is another possibility.

--
Andy

"David Johnstone" wrote in message
om...
Can somebody give me some advice here?

I have two left hands and I need to drill a 12cm
diameter hole in a steel plate about 1mm thick
(the top cover of a computer case).

The top of the case has black enamel laquer and
it would be nice if I could do it with minimum
damage to that and as neatly as possible.

What would the experts do here, and what tools
do I need? Are there maybe even places that do
things like that for you for a small fee?

TIA, David

Put two or three layers of masking tape on the case to prevent scratching.
Mark out the hole with a compass, and drill a small hole inside the circle
large enough to pass a jigsaw blade through. Then carefully cut round the
inside of the line using a jigsaw fitted with a metal cutting blade. Finish
off with a half round file then remove the masking tape.

I wouldn't try doing it with a fly cutter as this can be very dangerous
unless you know exactly what you are doing.

In article ,
"Ian Stirling" says...
Rob Morley wrote:
In article ,
"Ian Stirling" says...
doozer wrote:
I've never tried a jigsaw (I didn't have one when I was doing most of my
case modding) but I found drilling multiple holes, sawing it roughly
snip
Why not just use aviation tinsnips?

I doubt the OP has them.

Probably quicker and/or cheaper to go out and buy some than use some
of the methods that people are recommending. At least I don't think
anyone's mentioned Dremels yet.

Rob Morley wrote:
In article ,
"Ian Stirling" says...
Rob Morley wrote:
In article ,
"Ian Stirling" says...
doozer wrote:
I've never tried a jigsaw (I didn't have one when I was doing most of my
case modding) but I found drilling multiple holes, sawing it roughly
snip
Why not just use aviation tinsnips?

I doubt the OP has them.

Probably quicker and/or cheaper to go out and buy some than use some
of the methods that people are recommending. At least I don't think
anyone's mentioned Dremels yet.

Works well.
Carbide router bit, MDF guide.

In article ,
John wrote:
persons of a certain age used to use sheet metal hole cutters for radio
chassis:

A 120mm Q-Max? Think you'd find it would cost...

--
*Change is inevitable, except from a vending machine.

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 18 Feb 2005 19:20:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

A 120mm Q-Max? Think you'd find it would cost...

And you'd need an unobtainium Allen key with Arnie Schwarzenegger on
the end of it to use it.

In article ,
Andy Dingley wrote:
On Fri, 18 Feb 2005 19:20:31 +0000 (GMT), "Dave Plowman (News)"
wrote:

A 120mm Q-Max? Think you'd find it would cost...

And you'd need an unobtainium Allen key with Arnie Schwarzenegger
on the end of it to use it.

It's a spanner operation, but still hard work. There's
a (very expensive) hydraulic jack available for the
larger Q-Max cutters.

--
Tony Williams.

In article ,
Tony Williams wrote:
A 120mm Q-Max? Think you'd find it would cost...

And you'd need an unobtainium Allen key with Arnie Schwarzenegger
on the end of it to use it.

It's a spanner operation, but still hard work.

I've never seen a Q-Max that big, though. Do they exist?

There's a (very expensive) hydraulic jack available for the larger
Q-Max cutters.

Oh, hydraulic punches of course exist. I'd guess something like that makes
the holes in production. But a Q-Max to me is screw operated.

--
*I didn't fight my way to the top of the food chain to be a vegetarian.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Dave Plowman (News) wrote:

I've never seen a Q-Max that big, though. Do they exist?

RS 600-082 is 116mm for fans, at only £131-51 each.

Oh, hydraulic punches of course exist. I'd guess something like
that makes the holes in production. But a Q-Max to me is screw
operated.

RS 605-223 is the matching hydraulic pump kit, at
a bargain price of only £417-75.

I've used them to retrofit 118mm fans into steel
cabinet doors.

--
Tony Williams.

Tony Williams wrote:

In article ,
Dave Plowman (News) wrote:


I've never seen a Q-Max that big, though. Do they exist?


RS 600-082 is 116mm for fans, at only £131-51 each.


Oh, hydraulic punches of course exist. I'd guess something like
that makes the holes in production. But a Q-Max to me is screw
operated.


RS 605-223 is the matching hydraulic pump kit, at
a bargain price of only £417-75.

I've used them to retrofit 118mm fans into steel
cabinet doors.


Ther are various ways to make big holes in steel sheet.

One off - drill holes and use file.

Several off, get big Q-max punch or see if someone near has an old set
of flypresses and tools.

Production. CNC punch.

On Sat, 19 Feb 2005 12:59:12 +0000, The Natural Philosopher
wrote:

Tony Williams wrote:

In article ,
Dave Plowman (News) wrote:


I've never seen a Q-Max that big, though. Do they exist?


RS 600-082 is 116mm for fans, at only £131-51 each.


Oh, hydraulic punches of course exist. I'd guess something like
that makes the holes in production. But a Q-Max to me is screw
operated.


RS 605-223 is the matching hydraulic pump kit, at
a bargain price of only £417-75.

I've used them to retrofit 118mm fans into steel
cabinet doors.


Ther are various ways to make big holes in steel sheet.

One off - drill holes and use file.

Several off, get big Q-max punch or see if someone near has an old set
of flypresses and tools.

Production. CNC punch.

never thought of a treppaning tool low tech but works well
http://www.shoptask.com/tools/st112.htm
Lenny

"Lenny Brown" wrote in message
...
On Sat, 19 Feb 2005 12:59:12 +0000, The Natural Philosopher
wrote:

Tony Williams wrote:

In article ,
Dave Plowman (News) wrote:


I've never seen a Q-Max that big, though. Do they exist?


RS 600-082 is 116mm for fans, at only £131-51 each.


Oh, hydraulic punches of course exist. I'd guess something like
that makes the holes in production. But a Q-Max to me is screw
operated.


RS 605-223 is the matching hydraulic pump kit, at
a bargain price of only £417-75.

I've used them to retrofit 118mm fans into steel
cabinet doors.


Ther are various ways to make big holes in steel sheet.

One off - drill holes and use file.

Several off, get big Q-max punch or see if someone near has an old set
of flypresses and tools.

Production. CNC punch.

never thought of a treppaning tool low tech but works well
http://www.shoptask.com/tools/st112.htm
Lenny

Those things are dangerous, unless you are using a pillar drill (drill
press) or similar with the job securely clamped or bolted down.

I've seen two accidents using those things, the first a few years ago, was
someone with a sheet of metal (that wasn't clamped down properly) spun and
sliced the top off his finger. The second was about three weeks ago a guy at
the place I was working was using a pistol drill, the fly cutter (trepanning
tool) snagged, the drill spun round and broke his thumb.

It was somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "John"
saying something like:

persons of a certain age used to use sheet metal hole cutters for radio
chassis:

http://www.lawson-his.co.uk/scripts/...Hole%20Cutters

but as there aren't any chassis these days they're harder to find.

Ye gods. I remember those - still got them somewhere.
--

Dave

In article ,
Kaiser wrote:

Those things are dangerous, unless you are using a pillar drill
(drill press) or similar with the job securely clamped or bolted
down.
[snip]

Quite dangerous, more or less guaranteed to snag
especially on aluminium. We always run with the
belts on the pillar drill not too tight. In that
way when it snags the belts slip, rather than
the trepanning tool spinning in the chuck (OR,
worse still, breaking the taper of the chuck).

--
Tony Williams.