The following data refers to an orthogonal machining of mild steel with a single point $$HSS$$ tool. Rake angle of tool $$ = {10^ \circ },$$ uncut chip thickness $$=0.3mm,$$ width of cut $$=2.0mm,$$ single plane shear angle $$ = {36^ \circ },$$ shear strength of mild steel $$=450$$ $$MPa,$$ using Merchants analysis

The coefficient of friction between the chip and tool will be

The following data refers to an orthogonal machining of mild steel with a single point $$HSS$$ tool. Rake angle of tool $$ = {10^ \circ },$$ uncut chip thickness $$=0.3mm,$$ width of cut $$=2.0mm,$$ single plane shear angle $$ = {36^ \circ },$$ shear strength of mild steel $$=450$$ $$MPa,$$ using Merchants analysis

The shear force in cutting will be

A cutting tool is designated in 'Orthogonal Rake System' as: $$${0^ \circ } - {0^ \circ } - {6^ \circ } - {6^ \circ } - {25^ \circ } - {75^ \circ } - 0.8\,\,mm.$$$
The following data were given
$${S_0} = $$ feed $$=0.12$$ $$mm/rev$$
$$T=$$ depth of cut $$=2.0$$ $$mm$$
$${a_2} = $$ chip thickness $$=0.22$$ $$mm$$
$${V_f} = $$ chip velocity $$=52.6$$ $$m/min$$
$${\tau _s} = $$ dynamic yield shear strength $$=400$$ $$MPa$$
$${P_z} = $$ main cutting force $$ = {S_0}\,t\,{\tau _s}\left( {\zeta \,\sec y - \tan \gamma + 1} \right)$$

Where $$\zeta = $$ chip reduction coefficient and $$\gamma = $$ orthogonal rake.
The main cutting force $$\left( {{P_z}} \right)$$ and cutting power assuming orthogonal machining are

In certain machining operation with a cutting speed of $$50$$ $$m/min,$$ tool life of $$45$$ minutes was observed, when the cutting speed was increased to $$100$$ $$m/min,$$ the tool life decreased to $$10$$ minutes. The cutting speed for maximum productivity, if tool change time is $$2$$ minutes is