The smaller grinders spin at higher speeds and therefore the blades wear out much faster. A small grinder is typically 10000 rpm where as a large 9 Inch grinder spins at only 6500 rpm. Better models have vibration damping handles and some have safety clutches that prevent injuries to the user. The larger models also have a dead man switch which means that you have to hold the switch to the on position unlike smaller models which can simply be switched on and then let go of!

Angle grinders can be used to cut stone or metal or even grind stone or metal with the appropriate disk. I do not like abrasive disks as these are dangerous, so a diamond tipped disk is preferred and is much safer! Small size grinders are also available in Air powered.

Bench grinders

Bench grinders are almost exclusively used for sharpening of either tools or drill bits, although they can also be used for a hundred other uses!

The grinding wheels often become worn unevenly and need dressing with a dressing tool.

 
Cordless angle grinder

The latest innovation is the cordless angle grinder, with versions available from Bosch and Dewalt. These are currently available in 115mm (4.5 inch) and have the advantage that you cannot cut through the cord. Working at heights or outside is now much easier as there is no annoying trailing lead!

Die Grinders

Die grinders are used for polishing, wire brushing and metal removal on dies, stampings, gear teeth, plastics, tubes, castings and weldments.

Die grinders are also found in air powered which require compressed air from a compressor, these are often found in garages etc.