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Thread: Manual metal shears
07-13-2008, 02:59 AM #1
Manual metal shears
I'm a hobby metalworker and from time to time would sure like to be able to cut sheet metal. I know zip about metal shears. Are the manual shears any good for up to 16 ga.? I've never been near one and wonder how they actually work as well. Thanks if you can give me just a little bit of an introduction to them.
07-13-2008, 10:11 AM #2
Diacro has some very nice small shears and brakes which usually go for impressive prices.
Beverly makes a great "throatless" shear which is good for curves and can also make a decent attempt at a straight line with care. There are 3 sizes of the throatless shear and I think they can still be bought new. However, good used would still be more economical. I think new blades are also still available. This design takes up nearly zero space, about 8" square mounted on a sturdy bench as you have to keep pulling the lever down.
07-13-2008, 11:04 PM #3
Shears sounds like what Matt is describing, a bench mounted scissor action manual machine with a long handle for the mechanical advantage.
Sheet metal cutting machines are a shearing device of another category often referred to as a guillotine. The lighter version can be treadle operated but I think most are hydraulic.
I have a set of peddinghaus bench-mounted shears said to be capable of cutting 7mm, but I very much doubt it. It is also supposed to be able to cut 20mm square or round bar but again you will need your spinach for that too.
Although advantages are moderate cost and small footprint and much thicker cutting capacity than the average guillotine. Most are limited to 2mm thick mild steel sheet or 1.6mm stainless steel sheet.
Two of the major disadvantages with the manual bench-mounted shears apart from the effort involved are distortion of the metal being cut and the difficulty, I might suggest impossibility of cutting following a line through a wide piece of material such as cutting off a piece of a 4' wide sheet. Even having enough space and support for the sheet as you feed the material into the shears can be a problem.
A plasma cutter would be ideal in this situation but one is still on my shopping list.
07-14-2008, 12:20 AM #4
Thanks, Damien W. I suspected much of what you said, principally on making a clean, crisp cut. Coincidentally I was just looking at the cart my tig welder sits on and wondered if a plasma cutter would fit underneath it. Think I'll wait it out and see if Santa brings me one some day.
07-14-2008, 03:26 AM #5
You better be a good El Cazador because Santa will know if you're not.
And don't reject bench-mounted shears completely. There may be jobs that they can do admirably and if the opportunity to get one presents and the price is right you might be grateful to own such a tool.
And like Dirty Harry says, "A man has gotta know his limitations". And that applies to tools of every description also. Some (most) have desirable attributes but they all have limitations too.
Think of simple tools like the wrench used for tightening and loosening those spin-on oil filters on your car engine. I have about four of them but use only one. The others proved to be less effective and a waste of money. An yet I still believe there is a lot of room for improvement. It's like the miracle can opener get it right and become a multi-millionaire.
07-14-2008, 08:39 AM #6
One of the most useful tools I ever got my hands on was a little device that was a shear, nibbler, and rod cutter. This was about the size of what Matt describes, but in addition to the shear feature, had a hawkbill looking nibbler blade that could be exchanged for the shear blade. Made a lot of stuff with that.
Also had a Pexto 42" stomp shear that was just splendid.
07-14-2008, 10:13 AM #7
buy this tool first.
after using it you may still decide you still need a throatless, stomp, guilliotine, plasma, hydraulic, etc.......
but you may just decide it does all that well enough that you can save your pennies.
either way you will sure not regret having it.
07-14-2008, 10:59 AM #8
+1 on the hand-held shears: I went through a variety of sheet-metal cutting solutions.
I started with a wood working jig saw. In retrospect, this is not a terrible solution with the right blade, which is very, very fine tooth, 24tpi or better. The nice thing about this is that they're made to use with a clamp-on fence, so you can make decent straight cuts.
Scissor type shears & aviation snips -- works and well if you get the hang of using the aviation snips, but you need a grip like an ape. Cutting a straight line isn't their forte, but curves are good. I'd say they top out at about 18 ga.
Sawzall -- ugly cuts, hard to hold the work, loud, beats the h*ll out of the material, etc. but still earns it's keep on demolition work and structural steel.
Chinese 3-in-1 machines. I like the slip rolls and press-brake, but I could never get the shear adjusted to work well. It worked OK on 18 ga. aluminum, but thinner or tougher stuff just slipped between the blades which would flex.
Beverly style shears. These are *sweet* for certain jobs - like the aviation snips, they do well on curves, but don't do so well on straight cuts. My example has a 1/2" bar cutter, and you'd really have to eat yer wheaties to cut that, but it'll happily cut 3/8" all day long, even stainless. That's a nice feature if you do lathe work on small parts.
The shears that dsergison show are electric. They come in pneumatic as well, but that, of course, requires a compressor. They do OK with a fence for making straight cuts, but aren't exactly designed for it. They're a really good, relatively low cost solution to cutting sheet. Don't skimp on these tools - a cheaper one will have lower capacity and the shearing blades dull quickly. Kettler (sp?) is a good brand.
Regarding a "stomp shear", if your work requires really nice, straight edges, for example, to butt-weld with no additional dressing, these will do the job, but take up a lot of floor space, and they're pretty heavy. They won't do curves, either.
Forgot to mention: plasma... OMG, it's cool, but the cuts are ragged, and require dressing before welding since there is a bit of slag on the back. The best use for plasma, IMHO is stainless, which is hard on cutting tools.