Short answer
A hydraulic shear is an attachment that closes its jaw with a cylinder fed from the hydraulic circuit of an excavator and cuts metal by shearing it between two blades. The principle resembles a guillotine: the moving blade passes the fixed blade and the material parts along the cutting line. Because no heat or flame is involved it is a cold cutting method, which is why it stands out in dismantling steel structures, pipe, tanks and scrap metal. It is designed to cut metal and bring it down to a transportable size, not to crush concrete.
What a hydraulic shear is and how it works
A hydraulic shear mounts on the excavator boom and routes the machine oil to a cylinder inside its body. The cylinder closes the moving jaw, and the blade on that jaw passes right alongside the lower blade fixed to the body. The material caught between the two edges parts under shear stress along the cutting line. Where a pulverizer spreads its force over a wide face, in a shear the whole force is gathered on a single line.
The tip area of the jaw mouth usually carries a piercing tip. It serves to draw material into the jaw and to open the first entry in elements such as plate or pipe. Many models also have a guide section that stops the material escaping sideways during the cut; when material escapes, the blade edge takes a side load and the cut section is left irregular.
The blades are the working surfaces of a shear and are made of hardened steel. Cutting performance depends not only on how sharp the blade is but also on the clearance between the two blades; when that clearance grows, the material starts to bend instead of being cut. We come back to this adjustment in the maintenance section.
A shear cuts, it does not tear
The job of a shear is to part material by shearing it between two blades. Taking a section into the jaw and trying to tear it off by pulling with the boom is not cutting but tearing: the blade edge takes a side load, the cut is left irregular and the piece breaks free without control. Pulling before the cut is complete is one of the most common causes of cracked blades on site. If cutting slows down, the answer is not to pull but to regrip the material closer to the pivot.
Where it is used
- Steel structure dismantling: it cuts columns, beams and purlins in place in factories, hangars, warehouses and framed buildings.
- Tank, silo and pipeline dismantling: it makes cold cutting possible where flame cutting is unwanted or not feasible.
- Heavy industry and plant dismantling: it breaks down elements such as boilers, stacks, conveyors and platforms.
- Scrap yards and recycling plants: it reduces incoming metal to feed or haulage size and separates metal out of a mixed pile.
- The metal stage of reinforced concrete demolition: it brings the rebar and sections exposed after separation down to a transportable size.
Which problem it removes
The first problem a shear solves is hot work. Flame cutting produces sparks, fumes and heat; inside a tank that has held flammable residue, or in a dense operating plant, that is a risk management matter in its own right. A shear cut is cold and is made from the cab, so nobody has to stand next to the element being cut.
The second is speed and continuity. Work cut by hand advances in cycles of preparation, equipment setup and rest, whereas a shear does the same job in a single machine cycle. A shorter dismantling period is also a safety gain: every extra day spent on site is extra exposure.
The third is sizing. Metal that has been cut to a regular size can be stacked and uses truck volume efficiently. Long, irregular pieces both waste space in haulage and obstruct equipment moving around the site.
The fourth is separation. Taking metal out of the other materials and dividing it into types is the most valuable step in the recovery chain. A shear makes that separation possible at the moment of demolition or dismantling.
Cost logic: where the saving comes from
The economics of a shear are not read in a single line; the gain accumulates in places independent of each other.
- Scrap value: separated and sized metal is priced differently from a mixed, irregular pile. What that difference depends on is set out in detail in the scrap steel recovery guide.
- Haulage: neatly cut pieces use truck volume efficiently, so the same trip carries more value.
- Time: a shorter dismantling period saves not only labour but also site setup, hire and overhead.
- Equipment count: doing the cutting with an attachment on the excavator you already have removes the need to bring a separate cutting crew and its equipment to site.
- Consumable discipline: the blade set is the most decisive maintenance item on a shear. Working habits that protect the blade are a cost decision that feeds straight into the maintenance budget.
- Which line dominates depends on the type of work; when deciding between attachments, the comparison page that sets pulverizer, shear and crusher bucket side by side helps.
Everyday operation and maintenance
The first thing an operator learns is where in the jaw to take the material. Cutting force is highest close to the pivot; heavy sections are cut there and lighter material along the jaw. Trying to cut a heavy section at the blade tip stalls progress and strains the tip.
Blades are the decisive consumable on a shear. They are usually designed with more than one cutting edge, so when a blunted edge is retired the blade can be removed and turned to bring a fresh edge into use, giving more than one service life from a single set. The bolts in the blade seats should be checked to the manufacturer instruction, because a blade that works loose both spoils the cut and eats its own seat.
Blade clearance, the distance between the moving and the fixed blade, is the adjustment that governs cut quality, and it is usually corrected with shims. The setting is specific to the model and is taken from your manual or from us.
On rotating head models the shear positions itself on its own axis, so the machine does not have to be moved to grip a section at the right angle. In work at height and in confined spaces the gain is clear. In daily use the rotation is used with the jaw free, and the hose runs are checked regularly for tangling.
The remaining routine is short: check play in pins and bushings, grease them, look for leaks at the cylinder and hose connections, and watch jaw closing speed. All of it can be reviewed in a few minutes at the start of a shift.
Blade clearance is a silent cost line
A drop in cut quality is usually blamed on a blunt blade, when the cause is often growing blade clearance. As the clearance widens, material bends between the two edges instead of being cut; cutting force is wasted, burrs increase on the cut face and the blade edge can crack under side load. If cutting has slowed and the cut face is deteriorating, check the clearance setting before changing the blade.
Which carrier it fits
The first criterion in matching is carrier tonnage; the weight of the shear has to stay within what the machine can safely carry at the end of the boom. On long front high reach configurations the decision is made not by tonnage but by the reach and load curve published by the machine manufacturer, because the weight that can be carried falls as the boom extends.
The second criterion is where the work is done. Demolition shears are used at the end of an excavator boom, inside a structure and for cutting in place, and there reach and weight balance decide. In scrap and recycling yards a shear usually works on a material handler in a repeated cutting cycle, and there jaw opening and cycle speed come to the front. Which of the two your need resembles largely decides which shear you will be matched with.
On the hydraulic side two values are watched: the oil flow that sets jaw closing speed and the working pressure that sets cutting force. Some models have an arrangement that closes the jaw quickly when unloaded, and the attachment line of the machine has to suit it. If a rotating head model is chosen, rotation needs its own line and its own flow; whether the machine has that line should be settled at the outset.
On the mechanical side pin diameter, ear spacing and, where used, the type of quick coupler have to match; the weight of the quick coupler itself enters the calculation too. Rather than doing this matching by hand, enter the tonnage, oil flow and working pressure of your machine in the selector tool at /urunler/secim-araci to list the compatible models, then send us the result together with your site conditions for confirmation.