Double cut shears vs unishears

[rossn]

I'm in the middle of a pretty major remodel, and have a need to cut some long strips of 16ga sheet, as well as a little metal ducting. I'd like to buy tools that will also serve well in a metal shop... I now have a Lincoln MP210, but haven't had much time with it, due to the remodel.

It seems like a double cut shear or a unishear, combined with a small and large (10-ga) nibbler is a good long-term combo for metal work in a multi-purpose shop, where I'd like less airborne particles (such as using a grinder to cut). So, I am leaning towards a pair of 14ga shears.

What are the reasons I should consider 14ga double cut shears versus a 14ga unishears?

Any recommendations for finding a good (new or used) pair of electrics for a couple hundred bucks or less?

Thanks!

 

[neophyte]

Double Cut( ie. strip cut shears) are somewhat more versatile than the single cut unishears.

The unishear design needs to bend one side of the sheet netsl up, and the other side doen during cutting, so with thicker sheet metal, there can be a limit to how far from the edge of the sheet a cut can be made.
The strip cut shear design just needs to bend the strip of material between the single llwer, and two upper blades.

The strip cut shears can be used to trim material off the edge of a sheet like a unishear, including thin strips, although you might just have a dingle one of the upper blades cutting.
This however means that the strip cut shear has the same visibility as it cuts whether cutting left or right handed.

One major disadvantage of strip cut shears is that you loose the strip material during cuts, which is not the case with a unishear.
You also loose material with a nibbler.

The Unishears usually have adjustable cutting clearance for different gauges of sheet metal or different alloys.
Strip cut shears usually don’t, so this might cause issues with really thin alloys, or certain alloys depending on stiffness or tensile strength.

The strip cut shears like a nibbler can be started in the center of a sheet, with the right size hole drilled.
Same with a nibbler.
Unishears may be able to do this, but it usually requires a larger hole.

The main advantage with nibblers, is you don’t have to worry about starting at the edge, or the center of a piece.
Nibblers don’t have the strip of material possibly getting in the way during a cut.
Nibblers also usually have a much better turning radius than either Unishears or strip cut shears, particularly the Trumpf type with the round type dies.

The major issue with nibblers is the nibblers are basically a continuous hole punch, and drop little slices of metal all over the floor as you cut.
With square dies nibblers, these slices are mostly rectangular or polygon shaped.
With the round die nibblers, the slices are usually crescent moon shaped, and can get stuck to a huge degree in boot or shoe soles(square die nibbler pieces will as well).
Basically imagine a whole box of loose industrial staples getting stuck in your shoe soles.
The slices can also get stuck in you hands or knees if you have to crouch for something.
Trumpf and Draco both make bags that attach to the nibbler die to collect these slivers as you cut, but the charge a lot for the bags.

Basically, Unishears are probably better if you’re trimming material off the sides of sheats.
Strip cut shears are better if you’re dividing or working whole sheets including mid sheet cuts and cut outs.

Trumpf and Draco also offer cutting fences for cutting continuous strips of material( only for some shears though) and there are dome circle cutting attachments for some nobblers and shears as well.

A couple of the Trumpf doubke cut shears have a cutter to cut the strip off at the front.
Most other strip cut shears, including Draco and Kett, don’t.
Trumpf likely used to, and may still, make the cutting heads for nibbler and shears from other German/European manufacturers. This seems to have changed somewhat more recently, but was very common 10 plus years ago.
Draco makes shear heads for themselves, at least one Fein shear, and maybe Milwaukee in Europe.
I suspect Kett used to make the shear heads used by a number of USA manufacturers, at least if the shears used the “drill” type motor.
Kett cutting blades are usually way more afgordable that blades for German shears.

 

[neophyte]

I should have mentioned, a decent jigsaw, like a top of the line Bosch model, can also be easily used for cutting sheet metal as long as you buy decent blades, and buy them in large packs.
I’ve never really priced out the different costs, but nibbler punches and dies, and shear blades are significantly more expensive than quality jigsaw blades, to the extent you could probably purchase a 50 or 100 pack of blades for the cost or less of replacing a blades set for a nibbler or shear.

 

[rossn]

Thanks, Neo - definitely appreciate the time you took to share that info. I have read some of your other posts, and you seem to be very knowledgeable in this area.

I had not thought about the inability to use the unishear starting in the middle of the sheet, and that is a pretty big deal for center material removal.

It seems like for my use, the double cut shear is the place to start, later adding a nibbler. The Draco and Trumpf slitting shears seem really awesome, esp. the tighter cutting radius of them. However, they cost multiple times more than the Kett 440, which seems to have a good reputation, around $200 new. And, the german ones do not appear easy to find online. It looks like, unfortunately, the Kett doesn't allow the head to rotate 90 degrees, but I will call to confirm. I guess for most straight cutting (I'm not doing roofing material) that is fine, but it would be nice to have the flexibility.

The jigsaw is also a very interesting idea that I will definitely think on. The one I have is one of my cheaper tools, so there would probably still be a tool investment.

It looks like bosch stopped making corded models of their double cut shears, such as the 1521... too bad. Any other 14 ga. options that I should consider, similar to cost of the Kett?

 

[neophyte]

I think the Kett might be the only somewhat affordable “quality” shear, especially for 14 gauge.
Makita makes a strip shear, but I think it just maybe 16 gauge.
Sanwa is another manufacturer of industrial shears and nibblers from Japan, but their shear probably cost as much as the Trumpf and Draco shears.
Most of the other Euro shear producers are using Trumpf or Draco shear heads, and cost almost as much.
Some Dewalt nibblers and shears appear to use older Trumpf cutting heads, and are somewhat more affordable, especially in the USA, but O don’t believe this includes a strip shear.

Kett used to manufacture an inline shear closer to the style of the Trumpf/Draco shears, with a straight motor rather than a drill style motor.
I believe the 14 gauge version was the KL-240, found here.
https://www.mutualscrew.com/product/kett-tool-kl240-14-gauge-doublecut-shear-195111.cfm
It looks like this may gave been discontinued.
I’m not sure why, although the motor appears to have been a typical die grinder style motor, with a gear reduction to bring the speed down to that of the usual drill motors Kett typically uses.
It’s possible Kett was sourcing the motors from a Russian power tool manufacturer that is owned by a Russian aerospace parts manufacturer, so maybe there were supply issues( the Russian source is a guess based on similar motors and tools).
The inline version cost almost twice as much as the drill motor version, but it’s still less than half the price of a German shear.

As far as shear availability.
Trumpf has been selling shears in the US for decades, so while not the easiest things to find, I doubt they’ll disappear from the marketplace.
Draco is more obscure, but the shears seem to be showing up more thru roofing supply places and other specialty sources. This can always change, so Draco might be more of a gamble as far as future availability than Trumpf.
Fein also sells versions of both shears, and they’ve had distribution in PA from the 1960s or earlier.

Bone of the shear manufacturers, whether Kett, Trumpf, or Draco, use self nanufactured motors.
Trumpf in the past has used motors made by Fein, Milwaukee/AEG, Metabo, Bosch, and maybe others.
Draco used motors made by Fein, Milwaukee/AEG, Suhner, and maybe others.
Kett uses motors made by Black&Decker/Dewalt, Makita, and in the past Porter Cable, us that possible Russian made one.
If the motor or parts for the motor fail, parts should be available from sources other than the shear manufacturer including decent tool repair places.

Cutting blades for Kett shears seem to be readily available.
Trumpf shear blades should also be easy to find.
Draco blades might be harder.
Also, Draco makes double cut shears with blades for certain specific tasks like duct cutting, and serrated blades for seem cutting.

Another issue with the Trumpf and equivalent shears is the grease used in the motor housing.
Trumpf is very specific about this, and some older manuals lists possible alternative greases.
All were obscure, with the only one seemingly available other than the Trumpf grease in the US bring a Mobile grease that was also pretty obscure.
I presume there is a reason for the specific grease formulation, but don’t know why.
Trumpf also lists a seoarate grease for the cutting blades.

I believe Kett just specs a standardly available type of grease.

 

[Renegade1LI]

A metal cutting circ saw would be quick & clean, no sparks. I have a milwaukee & evolution both cut great, fast & clean, cut 1/4" all day

https://www.amazon.com/dp/B0000WUQI4/?tag=atomicindus08-20

 

[SHIFT]

I'm in the middle of a pretty major remodel, and have a need to cut some long strips of 16ga sheet, as well as a little metal ducting. I'd like to buy tools that will also serve well in a metal shop... I now have a Lincoln MP210, but haven't had much time with it, due to the remodel.

It seems like a double cut shear or a unishear, combined with a small and large (10-ga) nibbler is a good long-term combo for metal work in a multi-purpose shop, where I'd like less airborne particles (such as using a grinder to cut). So, I am leaning towards a pair of 14ga shears.

What are the reasons I should consider 14ga double cut shears versus a 14ga unishears?

Any recommendations for finding a good (new or used) pair of electrics for a couple hundred bucks or less?

Thanks!

My experience with double-cuts and unishears was for 18 - 24ga. commercial ductwork, so having the 14 ga. capacity variants wasn’t necessary. My double-cuts are an old Kett K-200 (18 ga.) and I have a 1500B Unishear (16 ga.).

Double-cuts excel at cutting round duct, in particular spiral pipe. Double-cuts are much faster and more aggressive than a Unishear, but not as accurate. A Unishear can cut circles and other complex shapes with (I think) as little as 4” diameter. But, a Unishear can be finicky and will require you to keep the tool and the material being cut in an optimal position to get a good cut. If the long strips that you noted need to be cut very accurately with a very straight and clean finished edge, the Unishear is the better choice.

Overall, the double-cuts tend to be a bit more versatile. I would probably start with Double-cuts and wait until I really felt I needed a Unishear before I bought one.

 

[rossn]

Thanks, Neo, Renegade, and Shift!

If seems like in shears, the Kett double cut 440 is the way to start, and keep an eye out for some craigslist specials on other varieties.

A metal cutting circ saw would be quick & clean, no sparks. I have a milwaukee & evolution both cut great, fast & clean, cut 1/4" all day

https://www.amazon.com/dp/B0000WUQI4/?tag=atomicindus08-20

All this said, @Renegade1LI, in reading up previously, I had run across other references to metal circular saws, but I had dismissed them, thinking they were for more heavy gauge metal. I'm now more intrigued and thinking if this would be a more versatile option. I understand there are some higher tooth blades that work with thinner gauge metal. Most of my sheet metal cuts would be straight, albeit, some short cuts of a few inches. How thin of a gauge can you practically cut with these saws?

I watched some videos on the Milwaukee saw, and it is pretty awesome.

Thinking more broadly... I would say 95% of the metal I would be cutting would be anywhere from 18ga-1/4" sheet or tubing up to 3/16" wall. The other 5% of the time, maybe there is some 3/8-1/2"+ rod/sheet or 1/4" wall tubing. Prices are not tremendously different, so I am all about buying the right tool for ease of use and the long-term.

Based on this, do you think I would be better off with the Milwaukee (less visibility) or Evolution (7" or 9"), and is one cleaner to operate than the other?

Of course, circular saws always have the reputation for being on the more dangerous end of the spectrum. Sawing metal, do you ever start to get lift or other situations where it feels like the saw wants to kick back?

Thanks!

 

[Renegade1LI]

Rossn, in my opinion, the milwaukee is a little bulky, but just takes a little getting used to, same for the evo it's also nice saw. To me for clean straight cuts these saws are the way to go, clamp a straight edge & cut I've never experienced kick back just don't force it or use a damaged blade. Both the milwaukee & evo do a pretty good job at capturing the chips, I don't think you could go wrong with either one.