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Grinding tools

A wide variety of abrasives used in conjunction with power tools must meet a wide range of requirements. The marking of the abrasives requires information about the following points:

1. the type of abrasive used,
2. bonding of the abrasive grain,
3. grain size,
4. hardness of the abrasive grain,
5. Structure,
6. dimensions, diameter and maximum peripheral speed.

Nicole Pinne-Wandmacher

The bond strength indicates how firmly the abrasive grit sits in the grinding wheel. A worn blunt abrasive grain should break out of the structure so that an adjacent unused grain can continue the grinding process.

Angle, straight, cup, disc, oscillating, eccentric, vertical, belt grinders, divided into one-hand and two-handed grinders.

vs = (d x n x p / 60) x (m / s)

d = diameter of the grinding wheel (m)
n = spindle speed (1/min)
p = 3, 14159

The rule of thumb is sufficient for a very quick determination:

vs = (spindle speed / 1000) x (wheel diameter in mm / 20)

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Grinding principle - Basics

Abrasive tools work according to different principles. In this training unit you will learn the principles of "linear", "rotation", "oscillation" and "oscillation and rotation". The following topics are covered: Materials, machine grinding, grinding principles, grinding tools, stock removal rate, surface quality, rough grinding, intermediate grinding, final grinding, workpiece shapes, work progress.

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Grinding principle - Linear

Abrasive tools work according to different principles. In this training unit you will learn about the "linear" grinding principle. The following topics are covered: Tool development, functional principle of belt grinders, stock removal rate, grinding quality, machinable materials, workpiece shapes.

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Grinding principle - Rotation (A)

Abrasive tools work according to different principles. In this training unit you will learn about the grinding principle "rotation". The following topics will be covered: Tool development, functional principle of angle grinders, stock removal rate, grinding quality, device types, machinable materials, workpiece shapes.

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Grinding principle - Vibration

Abrasive tools work according to different principles. The grinding principle "vibration" is explained here. The following aspects are covered: Tool development, functional principle of orbital sanders, stock removal rate, grinding quality, machinable materials, device types, workpiece shapes.

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Types of sanders and grinding machines

Eccentric sander / Random orbital sander

Power tool designed mainly for fine grinding of surfaces of various materials, such as wood, metal, glass and plastics. The mostly round grinding disc is eccentrically mounted on the drive shaft and can rotate freely or positively guided around its axis parallel to the work surface.
With forced guidance, the stock removal rate is increased considerably, so that coarse grinding work is also possible. With integrated dust extraction and adjustable control electronics and additional soft start, the random orbital sander is versatile.

Orbital sander

The orbital sander is mainly intended for fine grinding of surfaces of various materials. The orbital sander has a grinding plate that oscillates parallel to the working surface, usually rectangular.

Here you can find more information about orbital sander

Straight grinder

The straight grinder is mainly intended for peripheral grinding of various materials. The working shaft is in the direction of the motor shaft. In case of special design, the straight grinder is also suitable for other machine tools, for example milling cutters. As a rule, it has only one speed.

Multi grinder

Multi grinders are universal grinders that can be operated with one hand in all working positions. They combine the functions of orbital sanders and delta sanders. Their sanding plate resembles the sole of an iron in shape.
This makes them suitable for a wide variety of sanding jobs - along edges, in corners or on large surfaces.

Here you can find more information about multi grinder

Delta grinder

The delta or triangle sander is an orbital sander with a triangular sanding plate. The side edges of the equilateral grinding plate are convexly curved, resulting in the shape of the Greek letter "D" ("Delta"). This makes it possible to grind into sharp corners and along straight and curved edges. By using suitable extensions of the sanding plate, it is also possible to sand surfaces that are difficult to access, e.g. slats of shutters.

Here you can find more information about delta sander

Angle grinder

The angle grinder is mainly intended for side and peripheral grinding (cut-off grinding) of various materials. The working shaft is arranged at right angles to the motor shaft. Large angle grinders have only one speed, small angle grinders can have an electronically adjustable speed range.

Here you can find more information about angle grinder

Belt sander

Belt grinders are suitable ideal for precise and efficient sanding in tight spaces and hard to reach areas, such as spherical surfaces and pipes that are poorly accessible with normal grinding equipment. Our belt sanders are also ideal for deburring of all kinds and are a sensible and economical supplement for all grinding work.

Here you can find more information about belt sander

Fixing possibilities

Mounting

Depending on the type of machine and the shape of the abrasive, there are several fastening options.
The following variants are the most common:

  • Clamp
  • Fixing (velcro)
  • Sticking (adhasive)
  • Fixing

Fixing with clamp

Sanding papers are often attached to orbital sanders by spring clips.
Advantage: Cost-effective abrasive.
Disadvantage: Loss of surface due to clamping device, cumbersome operation.

1 Griding plate
2 Abrasive material
3 Clamp
4 Compression spring

Fixing with velcro

The quickest way to attach orbital and random orbital sanders is by means of a Velcro coating.
Advantage: No loss of surface, easy handling, even torn sandpaper holds.
Disadvantage: Somewhat more expensive.

1 Griding plate
2 Abrasive material
3 Felt cover
4 Velcro cover

Fixing with adhesive

Sanding papers are bonded to the sanding plate by means of spray adhesive or self-adhesive sanding paper.
Advantage: very good adhesion.
Disadvantage: Sensitive to dirt, cumbersome, not environmentally friendly.

1 Griding plate
2 Abrasive material
3 Adhesive layer
4 Smooth surface

Fixing with screw mount

Typical mounting method for rotary grinding machines. The abrasive (usually grinding or cut-off wheels) is clamped with a flange on the machine spindle. Pin-shaped grinding wheels are usually attached to the grinding machine by means of collets.
Advantage: Safety even at high power and speed.
Disadvantage: Technically complex.

1 Clamping nut
2 Abrasive material
3 Centring and driving flange