Bench grinders
Bench grinders
EXPERT KNOWLEDGE SANDING BLOCK
Structure and components
A typical bench grinder consists of a sturdy housing that protects the mechanical parts and increases safety during operation. The most important components are:
- Motor: Performance usually varies between 150 and 500 watts, depending on the Model and Use. A powerful motor ensures that the grinding wheels sanding discs rotate at a constant speed and enables Material to be removed quickly. The standard speed is approx. 3000 rpm. Bench grinders designed for sharpening (so-called low-speed grinders) often have a speed that is reduced by half. Reducing the speed significantly reduces the risk of annealing during sharpening.
- Grinding wheels sanding discs: The Bench grinder has two grinding wheels, each designed for different uses. One sanding block disc is often coarse to remove material quickly, while the other is finer and is used for sharpening and finishing. The Grit of the Grinding wheels sanding discs and the Type of Abrasive will significantly affect the results.
- Protective covers: These are important for safety and prevent sparks or small pieces of metal from getting into the user's eyes during sanding.
- Workpiece support: A stable support surface enables the user to guide the workpiece safely. This can be adjustable in height and inclination to find the best angle for sanding.
Grinding wheels sanding discs/grinding stones materials
Grinding wheels sanding discs can be made from various materials, including:
- Silicon carbide: Suitable for general grinding of steel and iron with high material removal.
- Aluminium oxide (aluminium oxide): Produces fine grinding surfaces with good material removal.
- CBN: These discs machine hardened steel without the risk of annealing.
Bit holder for the Grinding wheels sanding discs
Bit holders for the Grinding wheels sanding discs on a double sanding bench are usually provided with a shaft that is fitted with a thread. Common bore diameters for grinding wheels sanding discs are 12.7 and 15 mm. If the shaft diameter of the grinding machine and the Centre bore of the grinding wheel do not match, adapters are available to ensure that the discs can be mounted securely. For example, a 32 mm Centre bore of a CBN disc is reduced to a shaft diameter of 12.7 mm using a mounting flange.
Safety measures when using double grinders
The following safety measures are important when using a Bench grinder:
- Safety goggles: Wear safety goggles to protect your eyes from sparks and dust.
- Hearing protection: Use hearing protection.
- Secure footing: Place the Bench grinder on a stable and level surface to prevent it from wobbling during operation.
- Careful handling of hot workpieces: Allow the tool to cool down after sanding to avoid burns.
- Tight-fitting clothing: Tight-fitting waistbands on jackets prevent the risk of clothing being caught.
These measures help to minimise accidents and injuries when working with bench grinders.
