RRB ALP Fitter Trade — Solved Practice Question Bank

Q: Which type of fit is used for a permanent assembly requiring maximum tightness, such as a bearing pressed into a housing? Sol: Interference fit — it requires force to assemble and provides the tightest possible bond between the two mating parts. Q: A vernier caliper has 50 divisions on its vernier scale, with 1 Main Scale Division = 1mm. Find its Least Count. Sol: Least Count = 1 MSD / total vernier divisions = 1mm / 50 = 0.02mm. Q: If a micrometer shows a positive zero error of 0.02mm, how is a measured reading corrected? Sol: Subtract 0.02mm from the observed reading (positive zero error is always subtracted).

Q: What is the standard drill point angle used for general-purpose drilling in mild steel? Sol: 118°. Q: In a set of three taps used for threading a blind hole, which tap is used first? Sol: The taper tap — it starts the thread gradually with a tapered lead, followed by the second (plug) tap, and finally the bottoming tap to complete threading near the hole's bottom. Q: What weld defect refers to trapped gas bubbles inside the solidified weld metal? Sol: Porosity — it weakens the weld by creating internal voids.