Rotary, gantry or alligator shear: which one?
The three names buyers mix up
Search for “scrap shear” and you will find four different machines under one label. Buyers mix them up constantly, then compare prices between machines that are not comparable — a gantry shear quoted against an alligator shear is a quote against the wrong machine.
Here is what each name actually refers to, and which one your material needs.
“Rotary shear” — two different machines share the name
In scrap processing, “rotary shear” is used for two unrelated things, and it is worth knowing which one a supplier means:
- Rotary shear in a sheet or coil line — circular blades that cut strip as it runs. This is a processing-line machine, not a yard machine. If you are cutting coiled steel, this is what you want.
- Rotating shear attachment on an excavator — a jaw that rotates to angle the cut. It is an attachment, not a stationary machine. We list these as rotating eagle-beak shears.
Neither is the same as the large stationary shear most scrap yards buy. If a quote says “rotary shear” and you are cutting mixed yard scrap, ask which of the two they mean before comparing prices.
Gantry shear — the stationary workhorse
A gantry shear (also called a guillotine or stationary shear) holds material on a long loading table under a travelling blade head, and cuts it in one pass. The table is what makes it fast: a grab or magnet drops material along the length, and the blade works through it.
It is the right machine when you handle long sections, beams, plate and mixed yard scrap in volume. It needs floor space — the table is the machine.
Alligator (crocodile) shear — the compact cutter
A crocodile shear works like scissors: a moving blade pivots down onto a fixed bed knife. It is small, cheap to power and fast on short material — bar, pipe, angle, plate offcuts.
What it cannot do is swallow a bulky mixed load. It is fed by hand or a short conveyor, so labour sets the real throughput.
Box shear — the one that fits in a corner
A box shear loads material into a chamber, clamps it, and cuts with a horizontal blade. There is no long table, so it fits where a gantry shear will not — and it is usually fed by a grab dropping material in from above.
All four, side by side
| Machine | Feeds how | Best material | Floor space |
|---|---|---|---|
| Rotary shear (sheet line) | Continuous strip | Coil and sheet | Line length |
| Rotating shear attachment | Excavator arm | Demolition, site scrap | None — it is an attachment |
| Gantry / stationary shear | Long table, grab or magnet | Long sections, beams, mixed yard scrap | Large — the table is the machine |
| Alligator / crocodile shear | Hand or short conveyor | Bar, pipe, plate offcuts | Small |
| Box shear | Grab, from above | Bulky scrap, tight sites | Small to medium |
How to choose in sixty seconds
- Is the material long? Beams, rails, pipe over two metres → gantry shear with a table.
- Is the material bulky but short? → box shear.
- Is the material prepared, short and consistent? Bar, plate offcuts, sections → alligator shear.
- Is it on a demolition site rather than a yard? → excavator-mounted rotating shear.
- Is it coil or strip? → none of the above; that is a line machine.
Most yards end up with two of these, not one — a stationary machine for volume and an attachment for the awkward pieces.
Frequently asked questions
Can demolition shears cut both ferrous and non-ferrous scrap?
In practice, yes — a hydraulic shear will cut aluminium, copper and brass as readily as steel, because the blade does not care about the alloy. What changes is the result: non-ferrous material is softer, so it deforms rather than shears cleanly, and thin sections can fold between the blades instead of being cut. For non-ferrous you normally want a smaller shear, a tighter blade gap and a different cutting strategy — not a bigger machine.
Is a stationary shear the same as a gantry shear?
In most supplier catalogues, yes: “stationary shear” is used for the fixed machine, and “gantry shear” describes the frame style with the travelling head. Ask for the chamber size and blade length rather than arguing about the name.
Which is faster, gantry or alligator?
Gantry, for volume — but only because of the loading table, not the blade. An alligator shear fed by hand is limited by the operator, not the machine.
What decides the price difference?
Frame weight, blade length, hydraulic power and the loading table. A gantry shear carries far more steel than an alligator shear of the same cutting force, and that is most of the price gap.
Let’s put the right machine to work.
Tell us your material, required output and destination. We’ll discuss a suitable configuration with you.