Angle grinder

An angle grinder ( also power cutter Trennjäger, separation witch Schleifhexe, Feuerradl, Flex) is a mostly electrically powered hand machine with rapidly rotating circular grinding wheel. The grinding wheel is driven by an angular gear, which gives the angle its name. In 1954, the unit by Ackermann Schmitt or FLEX Power Tools GmbH from Steinheim an der Murr was introduced. Your brand name Flex is used in German as a generic name.

With a cutter with gasoline engine, however, is not a angle grinder, the blade is by design powered by a V-belt ( Typical Manufacturer: Stihl, Dolmar, Husqvarna ). Such machines are often used in track construction for cutting the rail pieces, as well as civil protection, to be able to approach work with collapsed power on Spilled can. Technically, this is a variant of the chainsaw, in which the guide bar has been replaced with belt drive and blade.

Principle

The round tool is rotating up to 13,300 revolutions per minute ( 115 mm disk diameter, 125 mm to 12,200 revolutions per minute), and is therefore subjected to high centrifugal forces. The theoretical average speed of the disks on the circumference is usually at about 80 m / s, the no-load speeds of for different wheel diameter ( customary 115, 125, 150, 180, 230 and 300 mm, the latter only as a cut-off machine ) built machines differ accordingly. To avoid bursting of the discs, these are reinforced by fabric inserts and possess, thanks to a particularly resilient synthetic resin bonding a degree of flexibility in comparison to rigid grinding wheels ( grinding stone) or surface grinding. This flexibility permits manual, hands-free abrasive cutting of metal, stone and other materials, without the grinding disc breaks in the case of a slight canting.

Tools

Depending on requirements, various tools are used:

• Cutting discs of fused alumina used for cutting metal, such silicon carbide for cutting stone. Separating discs for the grinding of stainless steel (both < 0.1%) free of iron, sulfur, and chlorine, to give the grid free. The grain of glazing for aluminum is not added by soft metals.
• Diamond blades for cutting stone, concrete and ceramic (eg paving stones and tiles).
• Grinding of fused alumina for processing of metal and stone (eg clean weld seams / edges break ).
• Flap discs for grinding ( surface and edge grinding) and polishing
• Sanding plate with fixed hook or an applied abrasive grain abrasive ( sandpaper ) with clamping or velcro fastening eg to rough rust from metal, removal of thick old paint layers, smoothing of rough wood, etc.
• Wire brush in pot or plate form, even in knotted execution of HSS wire, used for removing rust and cleaning as well as for welding and Lötvorbereitung.
• Coat wheels for polishing ( at reduced speed ).

Special form Twinsäge

The Twinsäge, unlike the ordinary angle grinder a gear driven with the two discs, which run in the opposite direction. This has the advantage that the two cutting disks each other freely admit the cutting room. This, and their carbide-tipped cutting blades is the saw will cut anything, because the leaves can enforce almost any material. The saw cuts all materials except concrete, stone, and after-treated steel, such as track rails. Likewise, this technique prevents snagging or Verspringen of the blades in the material. The Twinsäge is predominantly a piece of equipment of fire brigades or the Agency for Technical Relief (THW ).

As the normal cut-off machine, the Twinsäge in the cutting depth is limited by the blade radius.

Occupational safety

When working with angle grinders safety glasses, flame-retardant cotton clothing should be worn. When separating workpieces which then fall to the ground, safety shoes are useful. If the operation makes it possible angle should always be held with both hands; this is also true for the smaller so-called " one-hand angle ". Due to the high noise level, use of hearing protection is necessary for longer work. Must never be used without the appropriate protective cover of the device; this is not only the bursting of the disc is an important part, but also avoids touching the disc from the direction of the grips and controls of the machine.

Essential to avoid is the " Roughing " with Blades - here there is an increased risk of bursting, as these discs, the stabilizing fiberglass cloth is only applied externally and would rough grinding first looped through. The abrasive then has to oppose the strong axial forces nothing more. For rough grinding, there are either lock washers or thicker grinding discs, in which stabilizing fabric layers are still embedded in the abrasive.

All discs have a shelf life, which is specified by the manufacturer on the disk and is typically three years.

When working with angle grinders is formed as during all grinding processes, abrasion. Due to the high speed of the tool much heat is released at the machining point. In metal processing, especially in the grinding of steel and cast iron, the chips are therefore thrown glowing with high speed ( sparks ). If these glowing particles concentrated in larger quantities strike flammable material ( this includes the operator's inadequate clothing), there is an acute risk of fire when striking glass or ceramic surfaces ( eg tiles ) Einbrandgefahr. Likewise, grinding sparks can penetrate into crevices or cavities and cause hidden smoldering fires that may show only after hours flames.

When dry machining of stone and concrete, a suitable extraction is useful because of the strong dust. An alternative is, however, the wet cutting, the angle must be suitable for its protection of manufactures.

In industrial angle grinders used an annual safety check by U -VV audit is required ( according to the guidelines of the professional associations) in conjunction with the VDE regulations.

In popular culture

In the French horror film High Tension (2003), the killer does not use clichéd chainsaw, but a Stihl cut-off machine.