Cutting sheet steel

Since most builders only need to cut a batch of sheet steel occasionally,
why not try a water jet cutting service. A friend here in Perth was
rebuilding a car and had a new steel firewall made up from a CAD drawing at
very reasonable cost. There are plenty of service providers in the USA -
have a look at http://www.precisioncuttingservice.com/ in Savanna GA for
example.

One local company here in Perth has done many instrument panels out of sheet
aluminum.

Phil Maley
Perth Australia

One of the easiest ways to cut sheet 4130 is with a band saw. Use an
old metal cutting blade installed upside down (the teeth pointing up).
Run the saw at normal speed and feed in the material. Keep the
pressure up and it will go (melt) through like you are cutting butter.
Don't pause though, it is not so easy to get started again. Some have
also used the back side of the blade for this purpose with success.

O-ring Seals

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

Dear O-ring (and the Group),

I believe you'll find there's a bit more to it than that :-)

First off, the 'normal speed' you're referring to is for a woodworking bandsaw.
The down-side is that most woodworking bandsaws are fitted with a rubber
'tire' on their driver- & idler-wheels. Friction cutting steel (which is what
you're doing) will destroy the tire on the driver-wheel in short order.
Bandsaw tires are moderately expensive and can be hellishly difficult to
replace on some saws.

Metal-cutting bandsaws do not use tires. The wheels are sizes so that the
teeth overhang the edge of the wheel, not only for cooling but for clearing the
swarf.

You can set-up a metal cutting bandsaw for friction cutting if you have the
proper ratio pulleys (ie, increase the blade speed).

The popularity of this method hinged largely on the builder's ability to splice
their own blades because the original idea was to use common steel strapping.
Operated at high speed -- and cutting relatively thin stock -- the stuff does
in fact cut like butter, with a very attractive displace of sparks, too :-)
But the strapping was rapidly consumed and unless you were a dab hand at
splicing, ideally with a Do-All type butt-welder, there was no long-term
advantage over regular cutting.

All of this came about due to the difficulty of cutting relatively hard steel
in thinner gauges, which loves to strip the teeth off anything. .035 4130, you
can do pretty well using a regular bi-metallic 32T blade by simply rigging the
work to feed 'downhill' so that two teeth are in contact with the work.

I've responded to your message because it appeared to be addressed to me, even
though I was not the person who posted the original question. Someone else has
already offered the most practical solution, which is to track down a
stomp-shear and just whack those puppies out. But the fellow posting the
question implied he not only wanted to make the part but that he wanted to
acquire the tool, learn to use it, and make the parts himself. In that light I
thought telling him to buy a shear might be a bit much :-) ...but did mention
several other methods & tools for producing the parts. I think I even
mentioned bandsawing but I assumed he would know I meant with a metal-cutting
bandsaw.

Friction cutting is kind of fun but if your only means of splicing a blade is
to taper the piece and use hard solder, I think you'll find you can't use
strapping. Too thin; the splice fails due to the heat. And if you can't use
strapping I don't see much sense in ruining a good blade, unless you're trying
to cut 6xxx stock or a leaf spring or something like that and friction cutting
is your only option. Personally, I'd just whip out my phasor, give them
Klingons hell :-)

-R.S.Hoover

Jimmy Galvin wrote:
Save yourself a lot of aggravation. Do not buy anything from "Harbor
Fright". All they sell is junk and it never works like they say. You would
have a lot more fun throwing the money in your toilet and watching it swirl
around as you flush.


Harbor Freight has a $35 cutting tool that can handle the job according
to the advertised specs. It sorta, kinda looks like an angle grinder,
except that it has a short arm and a reciprocating tooth out one side.
I figure I can drill a 3/8" hole, clamp a 2x4 to each side of the sheet
as guides, and just make a run with the cutter. Anyone have experience
with these things? Do they leave a clean edge?






That does sound like a good time, but the HF tools will have to do for
me. I know they're junk for the most part. I also know that they're
cheap. When the most likely failure mode is, "It rusted into a single
solid mass", then it's hard to justify spending what it cost for
professional grade tools. I count on the HF tools not falling apart
until I'm done with the few times I need it.

--
http://www.ernest.isa-geek.org/
"Ignorance is mankinds normal state,
alleviated by information and experience."
Veeduber

"Ernest Christley" wrote in message
om...

Harbor Freight has a $35 cutting tool that can handle the job according
to the advertised specs. It sorta, kinda looks like an angle grinder,
except that it has a short arm and a reciprocating tooth out one side.
I figure I can drill a 3/8" hole, clamp a 2x4 to each side of the sheet
as guides, and just make a run with the cutter. Anyone have experience
with these things? Do they leave a clean edge?

That does sound like a good time, but the HF tools will have to do for
me. I know they're junk for the most part. I also know that they're
cheap. When the most likely failure mode is, "It rusted into a single
solid mass", then it's hard to justify spending what it cost for
professional grade tools. I count on the HF tools not falling apart
until I'm done with the few times I need it.

I stopped by the HF tool retail outlet in Tacoma today to buy a set of five
jeweler's loupe's (2x, 3x, 5x, 7x, & 10x) for $2.99. Noticed they had the
electric shear tool on sale for $29.99.

Rich S.

Regarding HF tools:

Cheap goods will always drive quality goods out of the market place, a fact
pointed out by Adam Smith more than 200 years ago.

Once the quality goods have been driven out, the price of the cheap goods will
then rise to the point where you will be paying high prices for junk. The
number of everyday examples that illustrate this point are too numerous to
mention but some examples all should appreciate are clothing, light bulbs and
automobiles.

In a dollar-oriented society there appears to be no easy solution for this
economic fact of life.

-R.S.Hoover

Regarding HF tools:

Cheap goods will always drive quality goods out of the market place, a fact
pointed out by Adam Smith more than 200 years ago.

Once the quality goods have been driven out, the price of the cheap goods will
then rise to the point where you will be paying high prices for junk. The
number of everyday examples that illustrate this point are too numerous to
mention but some examples all should appreciate are clothing, light bulbs and
automobiles.

In a dollar-oriented society there appears to be no easy solution for this
economic fact of life.

-R.S.Hoover
++++++++++++++++++++

Having a 'down' day?

If I understand you correctly...
today's cars are junk as compared
to decades ago?

Crummy brakes, steering, handling and
lousey gas mileage is what I remember
from those 'good old days'. Ditto for early
washing machines, tube TV's, ad nauseum.

The only thing that sticks with me about
Adam Smith is that he's dead and dead right
about self interest as the "invisible hand" that
guides the most efficient use of resources
as a consequence of economic freedom.

What that means to me in plain english is --
I buy some junk... and lotsa' good stuff.

I have faith in the 'common' man and his
choices in a free market system over the
long haul.

YMMV.

Barnyard BOb - practitioner of self interest

On 26 Nov 2003 02:52:25 GMT, (Veeduber) wrote:

Thanks RS for the additional information. Sorry, the post was not
intended for you that is just how it came out in the thread. In my
experience, and I have been doing this technique off and on for over
20 years, is that it has not harmed the tires on my old Craftsman wood
cutting band saw. I am not advocating using a "good" blade for this.
Many of us have sufficient old dull blades around for this purpose. I
tend to wear out blades rather than break them.

O-ring
--------------------------------------------------

Dear O-ring (and the Group),

I believe you'll find there's a bit more to it than that :-)

First off, the 'normal speed' you're referring to is for a woodworking bandsaw.
The down-side is that most woodworking bandsaws are fitted with a rubber
'tire' on their driver- & idler-wheels. Friction cutting steel (which is what
you're doing) will destroy the tire on the driver-wheel in short order.
Bandsaw tires are moderately expensive and can be hellishly difficult to
replace on some saws.

Metal-cutting bandsaws do not use tires. The wheels are sizes so that the
teeth overhang the edge of the wheel, not only for cooling but for clearing the
swarf.

You can set-up a metal cutting bandsaw for friction cutting if you have the
proper ratio pulleys (ie, increase the blade speed).

The popularity of this method hinged largely on the builder's ability to splice
their own blades because the original idea was to use common steel strapping.
Operated at high speed -- and cutting relatively thin stock -- the stuff does
in fact cut like butter, with a very attractive displace of sparks, too :-)
But the strapping was rapidly consumed and unless you were a dab hand at
splicing, ideally with a Do-All type butt-welder, there was no long-term
advantage over regular cutting.

All of this came about due to the difficulty of cutting relatively hard steel
in thinner gauges, which loves to strip the teeth off anything. .035 4130, you
can do pretty well using a regular bi-metallic 32T blade by simply rigging the
work to feed 'downhill' so that two teeth are in contact with the work.

I've responded to your message because it appeared to be addressed to me, even
though I was not the person who posted the original question. Someone else has
already offered the most practical solution, which is to track down a
stomp-shear and just whack those puppies out. But the fellow posting the
question implied he not only wanted to make the part but that he wanted to
acquire the tool, learn to use it, and make the parts himself. In that light I
thought telling him to buy a shear might be a bit much :-) ...but did mention
several other methods & tools for producing the parts. I think I even
mentioned bandsawing but I assumed he would know I meant with a metal-cutting
bandsaw.

Friction cutting is kind of fun but if your only means of splicing a blade is
to taper the piece and use hard solder, I think you'll find you can't use
strapping. Too thin; the splice fails due to the heat. And if you can't use
strapping I don't see much sense in ruining a good blade, unless you're trying
to cut 6xxx stock or a leaf spring or something like that and friction cutting
is your only option. Personally, I'd just whip out my phasor, give them
Klingons hell :-)

-R.S.Hoover

snipped
Operated at high speed -- and cutting relatively thin stock -- the stuff does
in fact cut like butter, with a very attractive displace of sparks, too :-)
snipped

As a Tool&Die shop owner for many years, I have friction-sawed a lot of
different materials and it is the only way to go when cutting stainless steel.

Your post was excellent and I would like to add one thing;
ASAP Aircraft Co., years ago, had some small, flat parts laser cut. Later, the
edges of the parts began showing small cracks caused by the intense heat of the
laser and they stopped using that method of cutting.
Friction sawing also produces heat. In fact, it melts the material.
I dont know if this would be a problem or not but I think I would normalize the
parts. Just to be on the safe side.

Warren

For lists of waterjet job shops in the USA or International visit the
following link:

http://www.waterjets.org/waterjet_jobshops.html
http://www.waterjets.org/internation..._jobshops.html

Or, call OMAX Corporation to ask for specific shops in your area:

http://www.omax.com (or 253 872 2300 or 800 838 0343)

- Carl



"Phil" philatwotechdotcomdotau wrote in message ...
Since most builders only need to cut a batch of sheet steel occasionally,
why not try a water jet cutting service. A friend here in Perth was
rebuilding a car and had a new steel firewall made up from a CAD drawing at
very reasonable cost. There are plenty of service providers in the USA -
have a look at http://www.precisioncuttingservice.com/ in Savanna GA for
example.

One local company here in Perth has done many instrument panels out of sheet
aluminum.

Phil Maley
Perth Australia

(Veeduber) wrote in message ...
One of the easiest ways to cut sheet 4130 is with a band saw. Use an
old metal cutting blade installed upside down (the teeth pointing up).
Run the saw at normal speed and feed in the material. Keep the
pressure up and it will go (melt) through like you are cutting butter.
Don't pause though, it is not so easy to get started again. Some have
also used the back side of the blade for this purpose with success.

O-ring Seals

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

Dear O-ring (and the Group),

I believe you'll find there's a bit more to it than that :-)

First off, the 'normal speed' you're referring to is for a woodworking bandsaw.
The down-side is that most woodworking bandsaws are fitted with a rubber
'tire' on their driver- & idler-wheels. Friction cutting steel (which is what
you're doing) will destroy the tire on the driver-wheel in short order.
Bandsaw tires are moderately expensive and can be hellishly difficult to
replace on some saws.

Metal-cutting bandsaws do not use tires. The wheels are sizes so that the
teeth overhang the edge of the wheel, not only for cooling but for clearing the
swarf.

You can set-up a metal cutting bandsaw for friction cutting if you have the
proper ratio pulleys (ie, increase the blade speed).

The popularity of this method hinged largely on the builder's ability to splice
their own blades because the original idea was to use common steel strapping.
Operated at high speed -- and cutting relatively thin stock -- the stuff does
in fact cut like butter, with a very attractive displace of sparks, too :-)
But the strapping was rapidly consumed and unless you were a dab hand at
splicing, ideally with a Do-All type butt-welder, there was no long-term
advantage over regular cutting.

All of this came about due to the difficulty of cutting relatively hard steel
in thinner gauges, which loves to strip the teeth off anything. .035 4130, you
can do pretty well using a regular bi-metallic 32T blade by simply rigging the
work to feed 'downhill' so that two teeth are in contact with the work.


I used to cut 4130 using the bandsaw method, with a 1/2" bimetal
blade installed the right way, and just letting the teeth round off
the first time I used it. It would cut rather nicely, and didn't hurt
the rubber tire. Keeping the cut straight was the biggest hassle.
There's a German-made friction-cutting tool designed to cut sheet
of all sorts using a steel wheel that doesn't spin but instead
oscillates at a fairly high frequency in an arc of about 20 degrees or
so. I saw it demonstrated on aluminum, steel and even stainless steel.
Really noisy, but a really clean cut, too. No chips. When the section
of the disc doing the work gets a bit dull, you loosen the screw and
rotate it a bit to a sharper section. I am trying to remember the
name, but can't. It was a big hit at our aircraft engineer's symposium
a couple of years ago. Not cheap, but well worth the cost if you're
doing much cutting.
Friction welding of aluminum aircraft skin was presented there,
too, though not demonstrated. Skins are butted together and a
high-speed carbide bit with a flat end and one raised tit are run over
the joint under pressure, the metal heats and fuses, and the alloy is
not affected so strength isn't hurt at all. I don't know how. You get
a flush, seamless joint with far less hassle than riveting. Also very
expensive. I think Airbus is using it on the A380, maybe.

Dan

Dan