Scrap Metal Shear Types: Gantry, Box, Inclined, Alligator
“Scrap metal shear” is a category name, not a machine. Under it sit four genuinely different designs — gantry, box, inclined and alligator — and the same 500-ton badge can appear on machines that share almost nothing but the word “shear.” Buyers who shop the category without distinguishing the designs end up comparing specifications that are not comparable. This article is the map: what each design is, what it is for, and which of the four our range actually builds, with the published boundaries that separate them.
For the buying framework that applies once you have picked the design, the shear buying guide is the next read.
The Four Designs
Gantry shear. A portal frame — four columns and an upper beam — with a vertically driven blade. Material is pushed into the cutting zone by a hydraulic feed, clamped by a hold-down cylinder, and cut by the descending blade. The gantry structure distributes reaction force across the frame, which is what allows the highest force ratings in the category: our range runs 200 to 2000 ton. Feeding is by excavator or grapple into a tank, cutting is on PLC presets, and the output is uniform charge length load after load. This is the production machine of the category.
Box shear (container shear). A horizontal box structure with a hinged lid. Material is loaded into the closed box — by grab, hopper or conveyor — compressed laterally, and cut by a horizontally advancing blade. The closed chamber contains splashing material, which makes it the design of choice where dust and safety control matter. Force ratings overlap with the gantry range, and the trade is the box’s containment against the gantry’s force ceiling and continuous-duty rating.
Inclined shear. An angled blade on a frame, designed so gravity assists feeding. The design shows up mostly in European catalogs; the pitch is that gravity-fed material reduces the feeding power requirement. What the pitch leaves out is that inclined feeding works on consistent material and struggles on irregular heavy scrap — the material most yards actually receive.
Alligator shear. A cantilever machine with a hinged jaw, hand-fed piece by piece. The most flexible and lowest-cost design in the category, and the one with the lowest force ceiling — our Q43-200 and Q43-250 cover the workshop and light-yard duty.
The Comparison That Matters
| Design | Feeding | Core advantage | Core limit |
|---|---|---|---|
| Gantry | Excavator / grapple into tank | Highest force, continuous duty, uniform cut length | Fixed installation, foundation required |
| Box / container | Closed box, grab or hopper | Contained cutting, safety and dust control | Force ceiling below gantry at the top of the range |
| Inclined | Gravity-assisted | Lower feeding power on consistent material | Struggles on irregular heavy scrap |
| Alligator | Hand-fed | Flexibility, lowest cost, no foundation | Force ceiling and throughput ceiling |
Notice that the designs are separated by feeding method and structure, not by tonnage. A 500-ton box shear and a 500-ton gantry are different machines for different yards, and a quotation that compares them on force alone is comparing the wrong row.
Which Designs We Build — and Why
Our range builds gantry shears and alligator shears, and the omission of the other two designs is deliberate rather than accidental.
Why gantry. The portal frame distributes reaction force across the structure, which is what allows continuous-duty ratings at the top of the range. For heavy scrap — the material that defines the category’s hardest jobs — the gantry is the design the duty conversation keeps returning to.
Why alligator. Plenty of operations need flexible, low-cost, foundation-free cutting for light material, and no gantry answers that job at that price. The alligator earns its place honestly.
Why not box or inclined. The box design’s containment advantage matters most where environmental control dominates the purchase — and where it does, the force ceiling becomes the constraint on exactly the heavy material those operations also receive. The inclined design’s gravity-feeding pitch works on consistent material and fails on the irregular heavy scrap that most yards’ intake actually contains. We would rather build the machine the material needs than the machine the catalog lists.
Choosing by Material, Not by Category
The design choice follows three questions, in order:
- What is the heaviest routine material? That answer alone eliminates designs. Heavy sections and plate eliminate the alligator; irregular heavy scrap eliminates the inclined.
- How is material loaded? Hand-feeding selects the alligator; excavator-feeding selects the gantry; grab-or-hopper loading into a closed chamber is the box’s case.
- What must the output be? Uniform charge length for a specification buyer selects the gantry’s PLC presets; workshop cutting to length is the alligator’s case.
Send the answers with your material profile and the quotation comes back within two business days naming the design and class your numbers support — the full range maps every gantry class from 200 to 2000 ton.
The Feeding Method Decides
Strip away the catalogs and the four designs separate on one axis: how material reaches the blade. Hand positioning selects the alligator — flexible, cheap, and capped by what a pair of hands can feed. Hydraulic feed from a tank selects the gantry — throughput set by the loading equipment rather than the crew, with the hold-down locking material that shifts under load. Grab or hopper into a closed chamber selects the box — containment and feeding flexibility against a lower force ceiling. Gravity-assisted feeding selects the inclined — lower power on consistent material, and a jam with the material’s weight behind it when the material is irregular.
That is why the design question is answerable before any tonnage comparison begins. Ask how your material is loaded today and how it could be loaded, and two of the four designs usually answer themselves.
The Force Class Follows the Design
One more separator belongs on the design map: the same nominal tonnage buys different material depending on the frame. A portal frame anchored in concrete distributes reaction force across four columns and an upper beam, which is what allows the highest force ratings in the category — our gantry range runs 200 to 2000 ton. A cantilever jaw concentrates force at the tip. A box chamber carries reaction through its structure. An inclined frame carries it through a different path again. When two listings quote the same tonnage on different designs, they are quoting the hydraulic system’s capability, not the material either machine takes shift after shift. Read the frame, then the number — and the full range publishes the boundaries per class.
The Duty Row Across Designs
One more row belongs on the design map, and it is the row buyers check least: the duty basis. A gantry build is quoted against a declared shift pattern — two shifts and three shifts are different builds, with frame, hydraulics, cooling and wear strategy all following the declaration. The other designs are typically quoted for lighter or intermittent duty, and a duty basis that is not stated is a duty basis that has not been engineered. When any listing quotes a tonnage, ask what shift pattern the rating assumes and what material it was measured on. The answers tell you whether the machine is a production tool, and that distinction decides more operations than the force number does.
The Design Question, Answered Once
The four designs answer four different questions, and the useful summary is one sentence per design. The gantry answers: what is the heaviest routine material, and can the site take a foundation? The box answers: is containment a requirement, and does the material suit a closed chamber? The inclined answers: is the material consistent enough to flow, and is the footprint binding? The alligator answers: is the material light, the volume modest, and the site temporary? Ask your operation those four questions in that order and the design names itself before any tonnage comparison begins.
Buyer FAQ
Is a box shear better than a gantry?
Different, not better. The box contains splashing material and suits dust-controlled sites; the gantry carries higher force ratings and continuous duty. The material and the site decide, not the catalog.
Why does the range not include inclined shears?
Gravity-assisted feeding works on consistent material and struggles on irregular heavy scrap — the intake most yards actually receive. We build the machine the material needs.
Can one yard run two designs?
Commonly, yes: an alligator for light workshop cutting and a gantry for production duty rarely compete for the same piece.
What force range does the gantry design cover?
200 to 2000 ton in our range, with the class boundaries published per model. The 315-ton class guide covers the mixed-yard middle of the range.
How do I know which design my material needs?
Send the three heaviest pieces from a normal month, the daily tonnage and how material is loaded. The recommendation comes back in writing, and it occasionally is the alligator. The design map is the first filter; the full range and its published boundaries are the second, and the written recommendation is where the two meet your numbers.
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