How it works, where it is used, and what factors to consider when choosing the right model for demolition, recycling, and waste management
The Sorting Grab for excavators is one of the most versatile attachments in the demolition and recycling industries: it allows you to grasp, move, and sort mixed materials directly on the pile, without the need for manual pre-sorting. Unlike a bucket, which collects material indiscriminately, the sorting grapple allows for precise sorting already during the handling phase.
At demolition sites, scrap collection centers, and recycling facilities, the Sorting Grab reduces processing time, lowers labor costs, and improves the quality of waste stream separation. In this guide, we’ll explore how it works, the types available, and the criteria for choosing the most suitable model.
How Does a Sorting Grab for Excavators Work?
The Sorting Grab is mounted in place of the bucket on the excavator’s boom attachment and is powered by the auxiliary hydraulic circuit. The mechanism consists of two or more articulated arms—known as tines—that open and close via one or more hydraulic cylinders. The material is gripped by compression and held between the tines during handling.
The feature that distinguishes the Sorting Grab from other grapples is the geometry of its tines: they are pointed, curved, and spaced apart in such a way as to filter out fine material while retaining larger pieces. This makes it possible to separate, for example, concrete from rebar, bulky waste from fine materials, or scrap metal from slag.
- Opening and Positioning on the Material: The operator activates the auxiliary control from the cab: the hydraulic cylinders open the tines to their maximum extent. The boom positions the grapple on the pile or structure to be picked up.
- Closure and Selective Screening:The tines close gradually; the coarser material is retained, while the finer material passes through the gaps between the tines. The closing force can be adjusted using the flow control valve.
- Rotation and Positioning (on Rotating Models)Models equipped with a 360° rotating joint allow the material being held to be rotated so that it is positioned correctly during unloading onto a truck, conveyor belt, or sorting bin.
- Discharge and Sorting: Selective discharge allows the material to be deposited at the exact desired location—stream by stream—reducing the number of passes and increasing the purity of the individual selected fractions.
Types of Sorting Grabs for Excavators
There are several configurations available on the market, each optimized for a specific type of material or operating environment. The main variants differ in the number of tines, whether or not they rotate, and their total weight.
| Fixed-Tine Grapple:Simple and sturdy design, with no rotating joint; Ideal for demolition and debris removal; Requires less maintenance than rotary models; Suitable for excavators weighing 6 metric tons and up; Lower purchase cost; Recommended for repetitive work in a fixed position | Rotary Sorting Machine| 360° Continuous Rotary Joint| Maximum operational flexibility in confined spaces | Ideal for sorting piles and loading onto trucks | Available in capacities of 8 metric tons and up | Greater precision in material positioning | Recommended for recycling centers and sorting facilities |
Main Applications in Recycling and Demolition
The Sorting Grab is used in a wide range of operating contexts. The following table summarizes the most common applications along with the recommended type of sorter.
| Application | Sorting Machine Type | Operational Notes |
| Sorting of ferrous scrap in a pile | Rotary, narrow tines | Separation of steel and non-ferrous metals; often combined with a magnetic separator |
| Sorting of demolition materials (concrete, wood, plastic) | Rotary or fixed, medium aperture | Sorting by material type before sending for recycling |
| Rubble Removal After Demolition | Fixed, wide teeth | Rapid handling of large quantities; secondary-grade quality |
| Loading bulky waste onto a truck | Rotary, high capacity | Rotation required to position the material in the vehicle’s tank |
| Separation of construction and demolition (C&D) waste (inert materials / metals / wood) | Rotary, medium tines | Typical application in construction and demolition (C&D) waste treatment facilities |
| Industrial Production Waste Management | Fixed or rotating, depending on the context | Suitable for machine shops, foundries, and the metalworking industry |
Table 1 — Main Applications of the Sorting Grab for Excavators.
Technical specifications to consider before purchasing
— Maximum opening and tine geometry
The maximum opening determines the maximum size of the piece that the sorter can grasp. The geometry of the tines—their number, curvature, and spacing—affects the machine’s ability to filter out fine material and its grip on coarse material. Narrow, curved tines are preferred for scrap metal; wider, straight tines are preferred for mixed debris.
— Closing force and load capacity
The closing force (in kN) determines the grapple’s ability to hold heavy or compact materials. The working capacity (in kg or t) is the maximum amount of material the grapple can safely lift. Both parameters must be compatible with the excavator’s auxiliary hydraulic circuit: always check the flow (l/min) and pressure (bar) available on the machine.
— Weight and compatibility with the excavator class
As with all hydraulic equipment, the weight of the grapple should not exceed 6–8% of the excavator’s operating weight. An undersized grapple reduces productivity; an oversized one compromises stability and causes excessive wear on the boom joints.
| Excavator class | Recommended weight for the sorting machine | Approximate maximum aperture |
| 6–12 t | 350–700 kg | 800–1,200 mm |
| 12–22 t | 700–1,400 kg | 1,200 – 1,800 mm |
| 22–35 metric tons | 1,400–2,400 kg | 1,600 – 2,200 mm |
| 35–50 tons | 2,400–4,000 kg | 2,000–2,800 mm |
Table 2 — Recommended match between sorter and excavator class. Values vary by manufacturer and model.
Operational advantages over manual selection
The introduction of a Sorting Grab at a demolition site or recycling center has a direct impact on processing times and costs. Manual material sorting requires dedicated personnel, is slow, and does not guarantee consistent quality in the separation of material streams. The excavator-mounted sorting grapple operates continuously, never tires, and maintains a constant production rate throughout the entire shift.
| Key Operational Benefits of the Sorting Gripper: Reductionin the number of staff required for manual sorting (1–3 fewer operators per shift)Increased productivity: a sorting cycle with an excavator takes 15–30 seconds, compared to 2–5 minutes for manual operations. Higher purity of sorted fractions: less cross-contamination between material streams. Flexibility: the same excavator can switch from the sorter to other attachments (crusher, shear) during the shiftSafety: eliminates operators’ exposure to unstable piles and sharp materials |
CMB Sorting Grabs
CMB Attachments manufactures Sorting Grabs for excavators in a wide range of sizes, suitable for machines from Class 6 up to over 50 metric tons. Available in both fixed-tine and rotating versions, CMB sorting grapples are constructed with Hardox steel for the tines and wear-prone components, undergo 100% testing prior to delivery, and offer rapid spare parts availability.
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Frequently Asked Questions About Excavator Sorting Grabs
What is the difference between a Sorting Grab and a standard grapple?
The terms are often used interchangeably, but in practice they refer to different configurations. The grapple (or polipo) is typically used for handling large volumes of bulk material (lumber, scrap) with sturdy tines and a high lifting capacity. The sorter has thinner, more widely spaced tines, specifically designed to filter fine material and perform precise sorting by type. In some catalogs, the two terms are used interchangeably: it is always helpful to verify the tine geometry with the supplier.
Can the Sorting Grab handle wet or muddy material?
Yes, but with some precautions. Wet material increases the overall weight of the load and can reduce the effectiveness of screening, as mud can clog the spaces between the tines. In these situations, we recommend tines with larger openings and models with specific wear-resistant coatings. Maintenance must be more frequent: lubricate the pins every 6–8 operating hours instead of the usual 8–10.
Is it possible to mount a Sorting Grab on a mini-excavator?
Yes, there are compact models for mini-excavators weighing 4–6 metric tons, used primarily in bulky waste management, public green spaces, and demolition work in confined spaces. It is essential to verify hydraulic compatibility: mini-excavators often have auxiliary circuits with limited flow rates (30–60 l/min), which requires sorters specifically designed for low flow rates.
How often should the teeth (tines) of a Sorting Grab be replaced?
The service life of the tines depends heavily on the abrasiveness of the material being processed. When working with scrap metal or demolition debris containing sand and concrete, standard steel tines last an average of 600–1,000 hours. CMB models with Hardox 500 tines can exceed 1,500 hours. Individual tines can be replaced in the field using standard tools, without having to disassemble the entire grapple head.
| Want to choose the right Sorting Grab for your excavator? The CMB technical team is here to help you identify the model best suited to your application, your excavator’s class, and the type of material to be handled. Contact us for a personalized assessment. → Contact the CMB team | Discover the range of material sorters |