GRAFS CG – machine for sharpening chipper knives and recycling blades

Introducing the GRAFS CG Grinder, the latest model available in our company’s product lineup. It is designed to meet the needs of customers who value robust construction combined with simplicity and easy machine operation.

The CG series is primarily designed for the recycling industry (e.g., mill knives) and the woodworking industry (e.g., chipper knives). Drawing from our expertise and customer feedback, we have created a product perfectly tailored for sharpening straight knives that do not require complicated processing.

The machine comes with electromagnetic chuck (available in lengths: 1000 mm and 1500 mm (depending on the order)). Each table in the CG model is equipped with a T-channel plate for securing knives using clamp brackets (e.g., planner knives). An optional feature includes the ability to order the machine with an adjustable angle of the grinding wheel motor (for grinding surfaces, including carbide inserts). The table also has special adjustable supports for knives from below, ensuring a uniform height of sharpened knives placed next to each other. This is particularly crucial for sharpening chipper knives or recycling knives where knife balance during operation is of utmost importance.

We reduced the required space for the machine, by installing the cooling system, (including the filter, tank, and pump), in an easily accessible location inside the machine’s body. The standard machine is equipped with a 120 L coolant tank and pump.

The machine features a convenient grinding wheel exchange solution. A specially designed holder developed in our company allows for easy and quick detachment and fastening of the grinding wheel using three clamping screws. Additionally, the machine carriage is designed to achieve the maximum space required for grinding wheel exchange, making the process very efficient.

The carriage is equipped with top-of-the-line cylindrical rollers (PWTR) moving on special hardened replaceable tapes. This design eliminates the need for continuous maintenance of carts and guides found in standard linear systems. Moreover, the CG grinder comes with a smooth feed speed regulation system (carriage travel). The machine excels in sharpening special-purpose knives that require high grinding speed, stiffness, and power, such as mill knives, crushers, or chippers.

The CG Grinder is a 100% Polish product built solely with European components.

The machine has undergone all necessary electrical tests, includes an instruction manual in English and comes with a Declaration of Conformity.

In summary, the GRAFS CG Grinder offers a powerful and efficient solution for sharpening straight knives in the recycling and woodworking industries. Its sturdy construction, user-friendly features, and top-notch components make it an ideal choice for businesses looking to achieve precision and productivity in their knife sharpening operations.

Easy operation by switches, down feed by manual hand wheel,
Smooth adjustment of the carriage speed from 1 to 12 m/min (using the potentiometer knob)
Powerful 4 kW grinding wheel motor, with additional bearings to eliminate any play.
Increased space needed to change the grinding wheel
Easy assembly of the grinding wheel (a special holder developed in our company enables quick installation of the grinding wheel with 3 clamping screws)
Possibility of mounting any grinding wheel (CBN, DIA, Segmentes) - from 150 to 200 mm in diameter
Scale for measuring the tilt angle of the electromagnetic table
Efficient sharpening of both soft and hard steels such as: NC11LV, HSS, WIDIA carbide
Internal tank with coolant pump (standard)
Rigid and strong structure without vibrations, body welded from 10 mm thick plates with ribs ensuring high stiffness, carriage and trolley made of 20 mm thick steel plates.
GRAFS CG series
Max grinding lenght
CG-1000e: 1000 mm / CG-1500e:1500 mm
Max grinding width
200 mm
Knife fixing method
Electromagnet, 1 unit: 150 x 1000 mm / 150 x 1500 mm (force 120N/cm2) + T-slot steel plate
Grinding wheel motor speed
1400 RPM (switched left / right)
Grinding motor power
4 kW (5,5 HP)
Carriage speed
1m/min - 12m/min (smooth regulation)
CG-1000e: 1200 kg / CG-1500e:1400 mm
length x width x height of the machine
CG-1000e: 2100 mm x 800 mm x 1600 mm / CG-1500e: 2400 mm x 800 mm x 1600 mm
400 V – 50 Hz – 3 f
Coolant filter efficiency
60 L/min
Coolant tank cappacity
120 L
Grinding wheel (every type: corundum, CBN, DIA, Grinding wheel with segments)
⌀ 150 - 200 mm
Magnetic chuck swivel range
+ / - 120 °
Mechanical infeed system
A special mechanism mounted to the hand wheel that allows you to start and regulate the infeed of the grinding wheel motor to the knife (in the range of 0.005 mm - 0.05 mm)
Magnetic Separator (Model MS)
Intended for filtering the machining liquid from the magnetic material.
Non-woven gravity separator (Model PS)
Designed for more efficient filtering of coolant, especially required when grinding carbides.
Knife holder
An adjustable stand for mounting knives, useful when cleaning the knife from coolant and burr after the sharpening / grinding process.
Upper scale indicating the infeed value / position of the grinding wheel motor (0.02 mm pitch)
Precise, adjustable scale to indicate the position of the grinding wheel motor or the amount of material machined.
Specialized all-day knife sharpening training
As a professional grinding shop, we offer training in the field of sharpening knives for chippers and recycling knives. Can be also in form an online meeting.



Very easy control of the machine using the side panel.

The speed of the carriage is set by the potentiometer knob. Simple on and off – grinding wheel motor, electromagnetic chuck, carriage ride and cooling system – with switches.


The tilting electromagnetic table allows for safe attachment of the object and precise setting of the grinding angle in the range of 0 to 90 degrees.

The second part of the table has the option of attaching sharpened knives with special clamps.

The table is additionally equipped with additional adjustable supports that allow for precise positioning of the knives from the bottom, in order to sharpen them evenly.

In the CG model in grinding lengths: 1000 mm, and 1500 mm. Chucks force is 120N/cm2.


The machine is equipped with an inverter to adjust the speed of the trolley from 1 to 12 m/min.,

All electronic components are high-quality products from proven European manufacturers.


The grinder is equipped with covers to prevent excessive dust from the cutting fluid escaping during grinding.

The amount of coolant fed to the machine by the pump can be freely adjusted.


Grinding wheel motor with a power of 4 kW, manufactured to individual order by one of the most well-known and respected manufacturers – CELMA INDUKTA. Equipped with a special holder developed by GRAFS for quick fastening of the grinding wheel with three clamping screws.

The motor is additionally equipped with special reinforced spindle bearings with elimination of axial play.


The processing liquid filtration module developed and built in our company consists of a magnetic separator with a rotating magnetic drum (for removing magnetic spoil), a steel tank with partitions, with a capacity of 120 L, and a coolant pump with a capacity of 60 L/min.

The whole has been installed inside the body, which allows to reduce the overall space needed for the entire machine.


The carriage’s driving system consists of two precisely machined steel guides covered with hardened strips of appropriate hardness.

High-strength PWTR rolling rollers (mounted in a trolley) move along the strips. This solution is more durable than standard linear systems used in CNC machines.


The machine is equipped with non-contact inductive sensors responsible for changing the direction of travel (feed) of the trolley.

The driving range can be freely adjusted with the bumpers. In addition, as a protection, the trolley is equipped with two emergency limit switches.




The carriage with the machine’s trolley can be manually positioned over the knife, which allows for safe positioning of the grinding wheel in relation to the workpiece. The carriage has properly machined bronze guides on which the sled of the grinding wheel motor moves. The entire system is adjustable and allows for many years of maintenance-free operation. We machine the trolley precisely on CNC machines. Constructed of welded steel sheets with a thickness of 20 mm. The trolley moves on 4 PWTR rollers with a diameter of 62mm (including 1 on an adjustable eccentric) for precise adjustment of the position of the rollers relative to the guides.
In addition, on one of the guides, 2 fixed internal rollers and 2 external adjustable rollers are used, which ensure uniform guidance of the trolley in relation to the body.



The body of the machine is made of 10 mm thick welded steel sheets with appropriate ribs. Before machining the guides, the body is stress relieved by vibration stress relief, which makes the entire structure extremely stable. The body of the CG model is available in two lengths, enabling the grinding range in the range of: 1000 mm and 1500 mm. The carriage’s driving system consists of two precisely machined steel guides covered with hardened strips of appropriate hardness. High-strength PWTR rolling rollers (mounted in a trolley) move along the strips. This solution is more durable than standard linear systems used in CNC machines.

Grinding machine for chipper knives and recycling blades