A generalized tool life equation for carbide tool for machining steel is given by
$$\,\,\,\,\,\,\,\,\,\,$$$$\,\,\,\,$$ $$V{T^a}{F^b}{D^c} = K,$$
Where $$V=$$ Cutting speed, meters/min,
$$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,$$ $$T=$$ Tool life,
$$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,$$ $$F=$$ feed, $$mm/rev,$$
$$D=$$ depth of cut in $$mm,$$ Indicates have magnitude $$a=0.3, b=0.3, c=0.15,$$

If the feed is halved and depth of cut doubled, for identical tool life of $$60$$ minutes, the percentage change in speed

Wall thickness of drawn cup is controlled by

A hemispherical cup of radius $$'R'$$ is formed in a press working operation. The radius of blank would be