How to Choose the Right Shears for Scrap Iron, Mixed Metals, and Industrial Recycling
Hydraulic shears for excavators are among the most in-demand attachments in the metal recycling industry: they allow for the cutting of steel structures, structural sections, pipes, and ferrous scrap directly on-site, reducing the volume of material to be handled and cutting down on disposal and transportation costs.
Choosing the right shear, however, is not as straightforward as it might seem. There are many different models on the market, varying in geometry, cutting force, and compatibility with excavators. In this guide, we’ll look at the key factors to consider before making a purchase.
How a hydraulic shear for excavators works
The Hydraulic Shear attaches to the excavator’s arm in place of the bucket. It is powered by the machine’s auxiliary hydraulic circuit: pressurized oil drives the internal pistons, which move the blades, generating the cutting force needed to sever the material.
There are four main components: the main body (with a swivel joint, if applicable), the interchangeable blades, the hydraulic cylinders, and the excavator attachment structure (pins and eyes in accordance with S standard or equivalent).
Rotary shears and fixed shears: operational differences
The first distinction to make is between rotary shears and fixed shears. The choice between the two types depends mainly on the type of work and the need for precise positioning on the material.
| Feature | Rotary shears | Fixed shears |
|---|---|---|
| Arm rotation | 360° continuous | Fixed / adjustable |
| Ideal application | Mixed scrap, ferrous | Cutting of metal structures |
| Cutting precision | High (on every corner) | Media (fixed position) |
| Compatibility | Mini and medium excavators | Medium-to-large excavators |
| Maintenance | More complex (joint) | Simpler |
Table 1 — Comparison of rotary and fixed shears for excavators.
At scrap yards and recycling facilities, rotary shears are generally the preferred choice: their continuous 360° rotation allows the blade to be positioned at any angle relative to the scrap, increasing hourly productivity and reducing the number of excavator movements.
Technical specifications to consider before purchasing
In addition to the type, there are four key technical parameters that should always be checked before selecting a Hydraulic Shear.
1. Hydraulic flow and pressure of the excavator
Each shear requires a minimum oil flow rate (expressed in liters per minute) and an operating pressure (in bar). Before purchasing, it is essential to verify that the excavator’s auxiliary circuit specifications are compatible with those required by the shear. Insufficient flow reduces cutting force; excessive pressure can damage the seals.
2. Cutting force and maximum opening
The cutting force (expressed in kN or metric tons) determines the thickness and type of material the shear can cut. The maximum jaw opening, on the other hand, indicates the size of the profile or tube that can be inserted. For mixed scrap metal, a generous opening is recommended to speed up work cycles.
3. Shear weight and excavator class
The weight of the attachment directly affects the excavator’s stability and operational safety. As a general rule, the weight of the shear should not exceed 5–8% of the machine’s operating weight. A shear that is too heavy for the excavator reduces maneuverability and increases the risk of tipping.
4. Quality of blades and replacement parts
The blades are the component most subject to wear. Assess the availability of original replacement blades, the type of steel used (Hardox 400/500 is the industry standard for abrasion resistance), and how easy they are to replace in the field. A system of easily interchangeable blades reduces machine downtime.
Quick checklist before purchasing:
- Check the hydraulic flow and pressure of your excavator’s auxiliary circuit
- Compare the weight of the shear to the machine’s operating mass (max 5–8%)
- Check the type of material to be cut: scrap metal, profiles, pipes, sheet metal
- Check the availability of replacement blades and the supplier’s delivery times
- Ask if the mount is compatible with the quick-release system already installed
Applications in the recycling industry: where shears make a difference
In the scrap metal processing cycle, hydraulic shears are primarily used in three stages: reducing the volume of demolished metal structures, cutting large-diameter profiles and pipes into pieces suitable for transport, and sorting by metal type in combination with grapples and magnetic separators.
Compared to stationary workshop shears, the excavator-mounted version offers the advantage of mobility: the operator can work directly on the pile of scrap, adjusting the shear’s position in real time without having to move the material to a fixed cutting point.
CMB hydraulic shears for recycling
CMB Attachments has been manufacturing Hydraulic Shears for excavators for over 30 years, with a product range covering excavators from Class 6 up to over 50 tons. All CMB shears are constructed with Hardox steel for wear-prone parts and are 100% tested prior to delivery.
The line of recycling shears is designed to maximize productivity when processing ferrous scrap, non-ferrous metals, and industrial demolition materials. To help you select the model best suited to your excavator and specific application, the CMB technical team is available to provide personalized advice.
Frequently Asked Questions About Hydraulic Shears for Excavators
Can I mount a shear on any excavator?
Not necessarily. It is essential to verify that the excavator’s auxiliary hydraulic system (flow rate and pressure) is compatible with the Hydraulic Shear’s requirements. You should also check that the mounting is compatible. Consult the excavator’s manual or contact the supplier for technical support before purchasing.
How long do the blades of a Hydraulic Shear last?
Service life depends on the type of material being processed and the frequency of use. When processing mixed ferrous scrap, Hardox steel blades may need to be replaced every 400–800 operating hours. Proper lubrication of the pins and periodic checks of the blade clearance significantly extend service life.
What is the difference between a demolition shear and a recycling shear?
Demolition shears are optimized for cutting reinforced concrete and steel structures on construction sites. Recycling shears feature jaw geometries designed to grip and cut irregularly shaped scrap, with cutting forces distributed across a wider opening to increase hourly productivity.
Are CMB shears compatible with quick-connect fittings?
Yes, CMB shears are available with standard attachments that are compatible with the main quick-coupling systems on the market. Please contact the CMB technical department to verify specific compatibility with your excavator and quick-coupling system.
Need help choosing the right product? The CMB technical team is here to help you select the hydraulic shear that best suits your excavator and your specific application. Contact us for a personalized assessment, or explore the CMB Shear line.