Brush diameter and trim length of fill material
The brush diameter and length of fill material are the determining factors for the surface working result. A combination of smaller diameter brush body and greater length of fill material results in soft and flexible brushes which are ideally suitable for the treatment of structured workpieces and for easy, gentle surface working. A larger diameter of the brush body and smaller length of fill material result in more aggressive brushes which can be used for deburring and removal of tougher dirt. For most efficient surface working, please select the maximum brush diameter, which can be mounted on the respective driving device. The peripheral speed and consequently the performance of the brush can be influenced by the brush diameter.
1. Brush Diameter
A large brush diameter achieves better results and a higher output. Large diameters (up to about 450 mm) are usually best with non-metallic fill material only. Size for portable tools should not exceed 7” for any fill material.
2. Trim Length
(Length of fill material extending beyond brush core or face plate). A short trim makes a stiff fast cutting brush, while a long trim gives a brush the flexibility required on irregular surfaces.
3. Face Width
Multi section brushes or multiple mounted single brushes have a wider face width and require more horse power.
4. Fill density
It is determined by the number of wire filaments per square surface area. Brushes with high density are used to produce finer surface finishes and also where fast cutting action is required; for example burr removing operations. Brushes with low density offer greater brush flexibility; where individual wires work like a whip.
5+ 6. Surface speed and contact pressure
The max. rpm speeds specified for power brushes are maximum safety speeds. In most operations, a lower speed than that specified will prove more efficient for you. Lower speeds and lighter pressure give longer brush life and require less power. It is important to remember that the tips of wire filaments do the actual work. Where high brush pressures and speeds are required, it is recommended that a more aggressive brush be used. This may be done by increasing wire size, decreasing trim length, or in some instances changing to another brush type.

Important: Portable machines must only be used with brushes with maximum 180 mm diameter!

Work- and safety r.p.m. during brushing
To entirely fulfill the requirements of workplace safety the maximum safety r.p.m. indicated on the products must not be exceeded under any circumstances.
The optimal work r.p.m. for the brushing of workpieces is defined by peripheral speed and brush diameter. The optimal r.p.m. during operation is therefore often appreciably less than the safety r.p.m.

Operating Speed & Maximum Safe Free Speed (MSFS)
To guarantee your safety, please select the largest possible brush diameter that can be used on your driving device. Standard values for safe peripheral speeds are approx. 30-35 m/sec for brushes with crimped wires, 18-22 m/sec for brushes with synthetic filaments and plastic bonded fill materials. For further recommendations of optimal work speeds and driving power, please refer to the tables listed in this catalogue or contact our technical service for assistance. Optimal positioning of the brush towards the work piece: The contact pressure of a brush is among other things defined by the depth of insertion in the work piece. Our recommendation is the 3-fold filament diameter, e.g. 1.0 mm depth of insertion for 0.35 mm diameter of wire. We are pleased to answer your questions regarding the optimal positioning of the work piece towards the brush centre. Please take into consideration that the brush wears out much faster if the positioning of work piece and brush is not accurate.