Holes of diameter $${25.0^{\matrix{ { + 0.040} \cr { + 0.020} \cr } }}\,\,mm$$ are assembled interchangeably with the pins of diameter $${25.0^{\matrix{ { + 0.005} \cr { + 0.008} \cr } }}\,\,mm.$$

The minimum clearance in the assembly will be

The flatness of a machine bed can be measured using

Which one of the following instruments is widely used to check and calibrate geometric features of machine tools during their assembly?

A metric thread of pitch $$2$$ $$mm$$ and thread angle 60° is inspected for its pitch diameter using 3-wire method. The diameter of the best size wire in mm is $${60^ \circ }$$ is inspected for its pitch diameter using $$3$$- wire method. The diameter of the best size wire in $$mm$$ is