I need to cut curves of small (And changing) radius in 22ga sheet steel. By
small, I mean in the one to three inch range. My 4x6 cheap Asian bandsaw
won't cut that small a radius. Snips are not precise enough (At least in my
hands) and I'm afraid a nibbler would be too time consuming.
I was looking at scroll saws, but couldn't find any metal cutting blades for
Any help appreciated. Thanks.
Roger in Vegas
I was born to Boogie.....
I'm just a late bloomer.
22 guage? Heck, I've done that. In fact I've done worse than that.
Maybe it's just my old, trusty pair of snips and constant use of files...
Maybe a hole saw?
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
My Harbor Freight throatless electric sheet metal shear will cut down to
around 1 inch radius. Fast and easy, although I think that the smaller
radiuses require more care. More info below.
Hand-held Power Metal Shears
Comparison of different styles
What is a Hand-Held Powered Metal Shear? These are portable power tools
running on electricity or compressed air. They have a reciprocating
blade that cuts sheet metal. Most of these units have a rated capacity
of 18 ga mild steel (0.040 inch or 1 mm thick). The price generally
ranges from $30 to $200 US.
Why would you want to use one? They cut accurately and rapidly along a
marked line These are much less expensive than plasma cutters and do not
generate sparks. The cut edge only needs to be deburred to be finished.
Since they are a power tool, they are easier on your hand than manual
snips. They are faster and easier to use than a sabre saw or
reciprocating saw. They are much smaller and cheaper than a foot
operated shear. They are probably most comparable to a Beverly type
shear, but Beverly shears are hand operated and bench mounted. I was
first exposed to these shears in a sculpture class that I took in
Mexico. I used one every day in class, and bought one as soon as I got home.
There are two types of these shears, the three blade type, and the two
blade type, sometimes called throatless.
The three blade type has two fixed blades, with a reciprocating blade in
the center. The reciprocating blade cuts out a strip of metal about 1/4
inch (6 mm) wide, which curls up as you advance the tool. This style is
particularly good at cutting large panels in two parts. It does not
distort the panel, the distortion ends up in the strip instead.
However, these units do waste some material (the width of the strip),
and cannot cut a tight curve (less than 6 inch radius). I usually use
mine to cut straight lines, and find it somewhat difficult to use to cut
curved lines. I use a Kett model KD200 shear of this type. This is a
good unit, although relatively expensive, but don't waste your money on
the nibbler attachment, it is very difficult to change from the shear to
The two blade or throatless type has one fixed blade and one
reciprocating blade. One side of the cut line is pushed up, and the
other is pushed down. This type does not waste any material, since it
does not produce a kerf strip. It will also cut relatively tight
curves, down to 1" or 1.5" radius. However, it does distort the panels
being cut. When used to cut large panels in half, the weight of the
panel and the distortion can make it troublesome to advance and control.
Sometimes, to facilitate more accurate cuts and to minimize panel
distortion, it can be advantageous to rough cut the panel about 1/4 inch
outside the cut line, and then go back and cut along the final cut line.
This was the style of shear that I used in Mexico, I think it was an
old Porter-Cable unit. I own a Harbor Freight shear of this type, cheap
and effective, but I had to do some shimming to get the cutting blades parallel.
Another hand power tool that can be used to cut sheet metal is a
nibbler. My air nibbler takes little "bites" out of sheet metal,
generating hundreds of sharp shards of steel in the shape of a new moon.
It cuts out a kerf about 1/4" (6 mm) wide. It can cut tight corners,
but is hard to keep going in a straight line. The cut edge is generally
very rough. I understand that some nibblers do not gernerate the sharp
shards, instead wadding up a strip of crumpled metal. Good for cutting
narrow slots or odd shapes in sheet metal, rather than cutting a piece
Each unit has it's place, which is why I have one of each type. I hope
that you find this useful in terms of choosing what kind of metal shear
December 2, 2003
Roger Hull wrote:
"Roger Hull" wrote: (clip) I was looking at scroll saws, but couldn't find
any metal cutting blades for them.
If you look at scroll saws which use plain-end blades (as opposed to
pin-end), you can use any blade material you can lay your hands on, by just
breaking off lengths.
Progressive cuts will do wonders just always stay on the scrap side of
the line. Final finish with file.
BTW, save a lot of layout work by drawing up in CADD and printing at
1:1. Stick drawing to stock with a _very_ light coat of spray
adhesive. Works great.
[ ... ]
This would be good advice with most bandsaws ,but not the 4x6.
The 4x6 imports are equipped with solid steel (or iron) wheels,
with a relief in just the right place to clear the teeth on a 1/2"
blade. Any narrower, and the teeth on one side get the rake crushed out
of them, so it will want to cut curves even when you want to cut
They are just made *only* for 1/2" blades.
They also have a rather limited throat, so you might not have
room for the scroll cuts anyway.
And immediately destroy it by mounting it on that particular
style of saw. You first need a saw with rubber tires to drive the blade
without damaging it.
You also need to be able to adjust the guide rollers to avoid
them crushing the rake out of the teeth. It *might* be possible, but
the saw really isn't made for the purpose. It is primarily a good
cheap horizontal cutoff saw. It pretends to be a vertical, but isn't
very good at it at its best.
On Mon, 5 Apr 2004 22:31:45 -0700, DoN. Nichols wrote
(in message ):
Adding rubber tires is a possibility. BUT the only 1/4" metal cutting blade I
can find in all my catalogs is in 100' rolls. Nobody seems to make it up into
loops of ANY size. I'm willing to take a stab at welding blades up, but don't
want to buy 100' if it can be avoided. All suggestions appreciated.
Roger in Vegas
Rake is something I grind into the blade, set is put in with a bit
As far as I know, the terminology is the same whether it's a jewellers
saw or a sawmill blade. Rake is a cutting angle, set is the offset
from center, side to side.
Did you search the screwed up yellow pages? There was a place in town
that would make them up for you. I got only one for my saw and it was
somewhere west of 15 around Flamingo. I probably found the place from
asking related businesses. BTW I have a little punch press , could
make it into a sorta nibbler...