Mechanical Metrology

Irregularities that occur in isolation or

infrequently because of specific causes such as scratches, cracks, and blemishes are called

• surface texture

• waviness

• lay

• flaws

The average height from a mean line of all ordinates of the surface, regardless of sign, is the

• RMS value

• Rz value

• Ra value

• Rm value

The Mecrin instrument assesses the surface

irregularities through

• fringe pattern

• air-leakage method

• frictional properties

• thermal properties

What characteristics of asperities are quantified

by the stylus instruments?

• Peakedness

• Heights

• Percentages

• Volumes

Peaks and valleys of surface irregularities are

called

• waves

• asperities

• manifolds

• perspectives

The indicator that enables the application of a pressure already decided upon on the screw thread in a bench micrometer is called

• a fiducial indicator

• a pressure indicator

• a span indicator

• none of these

What is dedendum for external threads?

• Radial distance between pitch and minor cylinder

• Radial distance between major and pitch cylinder

• Radial distance between major and minor cylinder

• Axial distance between major and pitch cylinder

Which of the following does not represent the major diameter of an external thread?

• Outside diameter

• Crest diameter

• Full diameter

• Root diameter

Which of the following is not true about effective diameter?

• Also known as pitch diameter

• It decides quality of fit between nut and screw

• This is the diameter of minor cylinder

• It is a very important dimension for screw threads

Which of the following is true for the multiple start screw threads?

• It is produced by a single helical groove

• Grooves should be different in spacing

• It gives a quick transverse

• It is formed in a transverse section on a cylinder