Formulae to be remembered
(a) V = π DN /1000
(b) Total length of tool travel L = l + A + 2
Where l = Length of the hole, mm
A = Breakthrough distance
= D/2 tan α [usually α = 59o ]
A = D /3.3286
(c) Time for drilling the hole t = L/ f N
(d) MRR = (π D2 f N ) / 4 mm3 /min ; D = Dia of the hole.