Required to avoid friction between the blade and workpiece
To prevent the hacksaw blade binding when penetrating into the material, and to allow free movement of the blade, the cut is to be broader than the thickness of the hacksaw blade. This is achieved by the setting of the hacksaw teeth. There are two types of hacksaw teeth settings.
5.8 mm
Silicon carbide
In grinding wheel following abrasives are used
The natural abrasives are emery and corrundum,These are impure forms of aluminium oxide.
Artificial abrasives are silicon carbide and aluminium oxide.
Make surface flat so that bolt head can take proper seat on the surface
Spot facing is a machining operation for producing a flat seat for bolt head, washer or nut at the opening of a drilled hole. The tool is called a spot facer or a spot facing tool. Spot facing is similar to counter-boring, except that it is shallower. Tools that are used for counter-boring can be used for spot facing as well.
