BM 1609929Y07 10-10:BM 1609929Y07 10-10 1/18/11 10:06 AM Page 14
Grinding Operations
SELECTING GRINDING WHEELS Before using a grinding wheel, be certain that its
maximum safe operating speed is not exceeded by the nameplate speed of the grinder. Do not exceed the recommended wheel diameter.
DISC GRINDING WHEELS
Grinding wheels should be carefully selected in order to use the grinder most efficiently. Wheels vary in type of abrasive, bond, hardness, grit size and structure. The correct type of wheel to use is determined by the job. Use disc grinding wheels for fast grinding of structural steel, heavy weld beads, steel casting, stainless steel and other ferrous metals.
GRINDING TIPS
Efficient grinding is achieved by controlling the pressure and keeping the angle between wheel and workpiece at 10° to 15°. If the wheel is flat, the tool is difficult to control. If the angle is too steep, the pressure is concentrated on a small area causing burning to the work surface.
Excessive or sudden pres- ! WARNING sure on the wheel will slow
grinding action and put dangerous stresses on the wheel.
When grinding with a new wheel be certain to grind while pulling tool backwards until wheel becomes rounded on its edge. New wheels have sharp corners which tend to “bite” or cut into workpiece when pushing forward.
CUTTING METAL
Using the optional type 1A wheel guard, it is possible to perform limited cutting on small stock such as metal tubes, piping or rebar. When cutting, work with moderate feed, adapted to the material being cut. Do not exert side pressure onto the cutting disc, tilt or oscillate the tool. When cutting profiles and square bar, it is best to start at the smallest cross section.
Always follow precautions for kickback.
Do not apply side pressure to cutting wheel to reduce wheel speed.
The tool should always be used so that sparks are directed away from user.
CUTTING MASONRY
Operate the tool only with dust extraction and additionally wear a dust protection mask. The vacuum used for this application must be approved for the extraction of masonry dust. Bosch sells suitable vacuum cleaners.
! WARNING When cutting masonry always use dust extraction with foot
plate. The tool may be used only for dry cutting. When cutting masonry use a dry diamond wheel.
Always cut towards the dust extraction port (Fig. 8).
FIG. 8
Turn the tool on and place the front part of the cutting guide on the workpiece. Slide the tool with moderate rate of feed, adapted to the material to be cut.
When doing deep cuts, it is best to cut in several shallow passes.
When cutting especially hard material, e. g., concrete with high pebble content, the dry diamond wheel can overheat and become damaged. This is clearly indicated by circular sparking of the rotating dry diamond wheel.
In this case, interrupt the cutting process and allow the dry diamond wheel to cool by running the tool for a short time at maximum speed with no load.
Noticeable decreasing work progress and circular sparking are indications of a dry diamond wheel that has become dull. Briefly cutting into abrasive materials (e. g. brick) can resharpen the wheel again.
