OT: Cutting a hole in 1.5mm/ 0.06 inch thick steel, any get-by technique?

[N Cook]

The sort of gauge used in casings.
Say something like a 3 inch diameter hole, fairly neat, so something neater
than chain-drilling then filing.
No fancy tools available eg no slow rev hand drill, fly-cutter on a mill etc

 

[Wayne Tiffany]

You might see if you can come up with a chassis punch. Here's one variety
http://www.oselectronics.com/ose_p64.htm. The best would be if you could go
to a shop and just use one there.

WT

 

[Dave Plowman (News)]

The sort of gauge used in casings. Say something like a 3 inch diameter
hole, fairly neat, so something neater than chain-drilling then filing.

That can be very neat depending on your skills. The best way would be a
hole punch like a Q-Max - but one that size would be very expensive.

No fancy tools available eg no slow rev hand drill, fly-cutter on a mill
etc

I'd probably use a holesaw but these too can be expensive for decent
quality ones. Otherwise a nibbler. But that might just come under 'fancy
tools'? Although the hand ones aren't that expensive. Monodex is one make.
There are power ones - air operated, driven via an electric drill, or self
contained electric.

 

[N Cook]

That can be very neat depending on your skills. The best way would be a
hole punch like a Q-Max - but one that size would be very expensive.


I'd probably use a holesaw but these too can be expensive for decent
quality ones. Otherwise a nibbler. But that might just come under 'fancy
tools'? Although the hand ones aren't that expensive. Monodex is one make.
There are power ones - air operated, driven via an electric drill, or self
contained electric.

--
*Go the extra mile. It makes your boss look like an incompetent slacker *

Dave Plowman [email protected] London SW
To e-mail, change noise into sound.

I was wondering about about those multi tooth ring cutters concentric to a
pilot drill, remove the unwanted ones, by turning backwards, to free.
Grinding
down most of the teeth leaving just those of one "set" say teeth 1...5...9
to reduce the bite that would stall a non-geared down drill, plus a
double-bunded
pond of cutting oil.

 

[Sam Goldwasser]

I was wondering about about those multi tooth ring cutters concentric to a
pilot drill, remove the unwanted ones, by turning backwards, to free.
Grinding
down most of the teeth leaving just those of one "set" say teeth 1...5...9
to reduce the bite that would stall a non-geared down drill, plus a
double-bunded
pond of cutting oil.

What's the material? Steel or aluminum? (Sorry if this was
mentioned.)

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[[email protected]]

There are various kinds of hand powered sheet metal cutters (metal
nibblers to) available on the market.I own a few of them.Some of the
sheet metal cutters are designed for cuttting straight, some for cutting
to the right, some for cutting to the left.Buy one of them.Drill a hole
in the sheet metal so you can get the metal cutter (metal nibbler)
started and cut out the metal.
cuhulin

 

[N Cook]

There are various kinds of hand powered sheet metal cutters (metal
nibblers to) available on the market.I own a few of them.Some of the
sheet metal cutters are designed for cuttting straight, some for cutting
to the right, some for cutting to the left.Buy one of them.Drill a hole
in the sheet metal so you can get the metal cutter (metal nibbler)
started and cut out the metal.
cuhulin

I've never used a nibbler but I seem to remember they give an up and down
ripple to the cut steel, due to the stop/start action and also any
sideways irregularity.

 

[Dave Plowman (News)]

I was wondering about about those multi tooth ring cutters concentric to
a pilot drill,

A holesaw?

remove the unwanted ones, by turning backwards, to free.
Grinding down most of the teeth leaving just those of one "set" say
teeth 1...5...9 to reduce the bite that would stall a non-geared down
drill, plus a double-bunded pond of cutting oil.

Most of the low priced ones aren't made for steel cutting - you need
types with hardened teeth for that. Or bi-metal ones where the teeth are
of a stronger material. But the exact size you want - I'm not sure. Maybe
for cutting downlighter holes. Here's a decent priced source of the
various types:-

http://www.screwfix.com/cats/A237680/Drill-Bits/Holesaws

But they don't give as 'perfect' a hole as a punch - it will still need
some dressing afterwards and a fairly slow cutting speed is better with
the larger sizes. Clamp the sheet to wood for the best cut so you can use
steady pressure.

 

[Dave Plowman (News)]

I've never used a nibbler but I seem to remember they give an up and
down ripple to the cut steel, due to the stop/start action and also any
sideways irregularity.

They won't give a perfect edge - but then the only thing that will is a
punch like a Q-Max. And a three inch one - even if available - will be
extremely costly.

 

[N Cook]

A holesaw?


Most of the low priced ones aren't made for steel cutting - you need
types with hardened teeth for that. Or bi-metal ones where the teeth are
of a stronger material. But the exact size you want - I'm not sure. Maybe
for cutting downlighter holes. Here's a decent priced source of the
various types:-

http://www.screwfix.com/cats/A237680/Drill-Bits/Holesaws

But they don't give as 'perfect' a hole as a punch - it will still need
some dressing afterwards and a fairly slow cutting speed is better with
the larger sizes. Clamp the sheet to wood for the best cut so you can use
steady pressure.

--
*Plagiarism saves time *

Dave Plowman [email protected] London SW
To e-mail, change noise into sound.

Appreciated, but it would only be for a one-off cut, so sacrificing a cheapo
holesaw, by grinding off most of the teeth, may well survive 2 jobs, one as
a test and one for real.
The undecided thing is what sacrificial backing material to reduce breakout
tearing, would denser MDFB be better than plywood?
Would cease cutting at first breakout be the best option, finishing off by
hand, a clean cut surface on one side only, is perfectly acceptable for this
job.

 

[Ron(UK)]

The sort of gauge used in casings.
Say something like a 3 inch diameter hole, fairly neat, so something neater
than chain-drilling then filing.
No fancy tools available eg no slow rev hand drill, fly-cutter on a mill etc

Depending on how close to the edge you are[1] a coping or fretsaw with
either a steel cutting blade or something like an abrafile + a little skill.

Or take a look at 'tankcutters' There used to be a hole saw availbale
specially for those MK chassis mounting 13 amp mains sockets.

[1] that`s the edge of the workpiece.. not your sanity

Ron(UK)

 

[Dave Plowman (News)]

Appreciated, but it would only be for a one-off cut, so sacrificing a
cheapo holesaw, by grinding off most of the teeth, may well survive 2
jobs, one as a test and one for real.

I think the problem is the real cheapies are wood only and simply won't
cut steel at all. One which *can* cut steel will work unmodified.

The undecided thing is what
sacrificial backing material to reduce breakout tearing, would denser
MDFB be better than plywood? Would cease cutting at first breakout be
the best option, finishing off by hand, a clean cut surface on one side
only, is perfectly acceptable for this job.

Any wood type stuff that is solid enough to support the work - so 1" or so
MDF would be fine. But a holesaw doesn't give a perfect cut on either side
as the pilot, being a drill, doesn't locate it accurately. Might be
possible to drill a pilot and replace the drill with a plain rod to help
location - but I wouldn't bet on it. To be perfectly honest the amount of
hand finishing and skill required to get a decent hole will be fairly high
no matter how you make the hole without a punch - so for a one off I'd
just drill a series of holes and file true afterwards. A decent half round
file will be cheaper than all the alternatives and needed anyway.
You scribe the circle and cut under size. Then file to the line bit by
bit with the sheet supported between two scraps of MDF etc in the vice
jaws.

 

[N Cook]

I think the problem is the real cheapies are wood only and simply won't
cut steel at all. One which *can* cut steel will work unmodified.


Any wood type stuff that is solid enough to support the work - so 1" or so
MDF would be fine. But a holesaw doesn't give a perfect cut on either side
as the pilot, being a drill, doesn't locate it accurately. Might be
possible to drill a pilot and replace the drill with a plain rod to help
location - but I wouldn't bet on it. To be perfectly honest the amount of
hand finishing and skill required to get a decent hole will be fairly high
no matter how you make the hole without a punch - so for a one off I'd
just drill a series of holes and file true afterwards. A decent half round
file will be cheaper than all the alternatives and needed anyway.
You scribe the circle and cut under size. Then file to the line bit by
bit with the sheet supported between two scraps of MDF etc in the vice
jaws.

--
*I speak fluent patriarchy but it's not my mother tongue

Dave Plowman [email protected] London SW
To e-mail, change noise into sound.

I hadn't considered that problem, so replacing the drill bit with a rod, or
even a conical centre of some sort, after pilotting.
Even if the most external point of the crude holesaw, little more than
scratched a trough say about 0.5mm deep , it would be easier and neater (my)
hand finishing to that, because you can then angle the file, rather than
first time all round, hit a blued line.

 

[[email protected]]

Maybe a piece of scrap pipe about the outside diameter of the hole you
want in the thin metal.Grind a sharp edge on the outside (or inside) of
one end of the pipe and use a heavy hammer.Try it on a piece of scrap
metal.It might work.
cuhulin

 

[jakdedert]

I was wondering about about those multi tooth ring cutters concentric to a
pilot drill, remove the unwanted ones, by turning backwards, to free.
Grinding
down most of the teeth leaving just those of one "set" say teeth 1...5...9
to reduce the bite that would stall a non-geared down drill, plus a
double-bunded
pond of cutting oil.

The cutting oil is a good idea, essential even. That said, I don't
think you want to be grinding on a saw blade of any kind. Aside from
the difficulty in obtaining any kind of precision, the heat generated
will degrade the steel.

Has anybody used those hole cutters which are a pilot bit with a single
carbide 'knife' on the end of an adjustable arm? I've seen--but not
used--them.

I'd think the OP would need to either do a lot of filing, buy an
expensive tool (punch)...or have the job done in a machine shop.

It all depends on the degree of precision required. Perhaps a less
precise hole would suffice, if some sort of escutcheon or trim ring will
work in the application.

jak

 

[[email protected]]

If you do any grinding, be sure to wear something to 100 percent protect
your eyes.About ten years ago, I was grinding a drill bit.A tiny spect
of metal or piece of the grinding wheel got into my right eye.I wound up
going to the VA Medical Center to have it removed from my eye.I wear
eyeglasses, but my eyeglasses didn't keep that little piece of grit out
of my eye.
cuhulin

 

[N Cook]

I was wondering about about those multi tooth ring cutters concentric to a
pilot drill, remove the unwanted ones, by turning backwards, to free.
Grinding
down most of the teeth leaving just those of one "set" say teeth 1...5...9
to reduce the bite that would stall a non-geared down drill, plus a
double-bunded
pond of cutting oil.

The cutting oil is a good idea, essential even. That said, I don't
think you want to be grinding on a saw blade of any kind. Aside from
the difficulty in obtaining any kind of precision, the heat generated
will degrade the steel.

Has anybody used those hole cutters which are a pilot bit with a single
carbide 'knife' on the end of an adjustable arm? I've seen--but not
used--them.

I'd think the OP would need to either do a lot of filing, buy an
expensive tool (punch)...or have the job done in a machine shop.

It all depends on the degree of precision required. Perhaps a less
precise hole would suffice, if some sort of escutcheon or trim ring will
work in the application.

jak

I don't think I'll try hammering bits of pipe.

I'd only be grinding the tips off 3 in 4 teeth, as the sheet is only 1.5 mm,
I don't see doing that would be generating enough heat to affect the
remaining ones.

 

[msg]

jakdedert wrote:

Has anybody used those hole cutters which are a pilot bit with a single
carbide 'knife' on the end of an adjustable arm? I've seen--but not
used--them.

Drill press fly cutter; I use one frequently on light gauge steel,
most any thickness aluminum and wood. Much easier to control and more
accurate than any hollow hole saw. For clean cuts, stop before final
penetration, invert the piece and finish from the rear (if possible).

Michael

 

[Ron(UK)]

The sort of gauge used in casings. Say something like a 3 inch diameter
hole, fairly neat, so something neater than chain-drilling then filing.
That can be very neat depending on your skills. The best way would be a
hole punch like a Q-Max - but one that size would be very expensive.

No fancy tools available eg no slow rev hand drill, fly-cutter on a mill
etc
I'd probably use a holesaw but these too can be expensive for decent
quality ones. Otherwise a nibbler. But that might just come under 'fancy
tools'? Although the hand ones aren't that expensive. Monodex is one make.
There are power ones - air operated, driven via an electric drill, or self
contained electric.

--
*Go the extra mile. It makes your boss look like an incompetent slacker *
Dave Plowman [email protected] London SW
To e-mail, change noise into sound.

I was wondering about about those multi tooth ring cutters concentric to a
pilot drill, remove the unwanted ones, by turning backwards, to free.
Grinding
down most of the teeth leaving just those of one "set" say teeth 1...5...9
to reduce the bite that would stall a non-geared down drill, plus a
double-bunded
pond of cutting oil.

The cutting oil is a good idea, essential even. That said, I don't
think you want to be grinding on a saw blade of any kind. Aside from
the difficulty in obtaining any kind of precision, the heat generated
will degrade the steel.

Has anybody used those hole cutters which are a pilot bit with a single
carbide 'knife' on the end of an adjustable arm? I've seen--but not
used--them.

I'd think the OP would need to either do a lot of filing, buy an
expensive tool (punch)...or have the job done in a machine shop.

It all depends on the degree of precision required. Perhaps a less
precise hole would suffice, if some sort of escutcheon or trim ring will
work in the application.

jak

I don't think I'll try hammering bits of pipe.

I'd only be grinding the tips off 3 in 4 teeth, as the sheet is only 1.5 mm,
I don't see doing that would be generating enough heat to affect the
remaining ones.

Whatever you do, make sure that the workpiece is well clamped down, if

it grabs you could be in trouble otherwise.

Ron(UK)

 

[default]

Has anybody used those hole cutters which are a pilot bit with a single
carbide 'knife' on the end of an adjustable arm? I've seen--but not
used--them.

Yes. If you have a drill press with a vise, cutting oil and use a
reasonably slow speed and slow feed it will do a bang up job - only on
(very) flat material and mild steel, cold rolled steel etc..
--