ISRO Technician-B Fitter Question Paper - 2016 (Set - 2) with Answer Key

If the strength of material to be drilled is high, the drill speed should be Low.

Spindle Speed is
RPM = (speed)/(circumference)
=(Speed)/(Pi x Diameter)
=44*1000/(3.142 x 20)
=700 RPM

Cast iron does not require any coolant because, graphite in the cast iron acts as a lubricant.

As per the Indian standard (IS) system, a drill bit is designated as 9.5-H-IS5101-HS, in this the number 9.5 stands for drill diameter.