What tool do I need?

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
them.
Any help appreciated. Thanks.
Roger in Vegas
I was born to Boogie.....
I'm just a late bloomer.
Reply to
Roger Hull
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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?
Tim
-- "I have misplaced my pants." - Homer Simpson | Electronics, - - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting and Games:
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Reply to
Tim Williams
I use jewelers saw blades in my $1.25 table top scroll saw to cut steel to 1/8 thick. Just don't push it too hard. Gerry :-)} London, Canada
Reply to
Gerald Miller
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 nibbler.
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 in half.
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 to purchase.
Richard Ferguson December 2, 2003
Roger Hull wrote:
Reply to
Richard Ferguson
Why not just put a narrower blade on your bandsaw? A 1/4" blade can turn a tight curve.
Get a fine tooth blade for sheet metal that thin.
Reply to
Ernie Leimkuhler
An air nibbler is very fast and can cut a small radius:
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They also make an electric version:
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Best Regards, Keith Marshall snipped-for-privacy@progressivelogic.com
"I'm not grown up enough to be so old!"
Reply to
Keith Marshall
"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.
Reply to
Leo Lichtman
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.
Ted
Reply to
Ted Edwards
If you _need_ to do these, as part of another project, consider getting them laser cut. Not inexpensive, until you figure in what your time is worth. Then the price usually compares favorably.
Reply to
Wayne Bengtsson
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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 straight.
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.
Good Luck, DoN.
Reply to
DoN. Nichols
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
Reply to
Roger Hull
Rake is something I grind into the blade, set is put in with a bit cruder tool.
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.
Reply to
Lennie the Lurker
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...
Reply to
Sunworshiper

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