If under a condition of plain turning the life of the cutting tool decreases by $$50\% $$ due to increase in the cutting velocity by $$20\% $$, then what is the $$\% $$ increase in tool life due to reduction in the cutting velocity by $$20%$$ from its original value.

While turning a $$C15$$ steel of $$160mm$$ diameter at $$215rpm,$$ $$2.5mm$$ depth of cut and feed of $$0.16mm/rev$$ by a tool of geometry $$0-10-8-9-15-75-0mm,$$ the following observations were made. Tangential component of the cutting force $$=500N,$$ axial component of the cutting force $$=200N,$$ chip thickness $$=0.48mm.$$ Determine the dynamic shear strength of the work piece material.

Diamond wheels should not be used for grinding steel components

Among the conventional machining processes, maximum specific energy is consumed in