Match the measuring feature with the corresponding measuring instrument in the table below. 
- P – 1 (Flatness error of a surface plate and Auto collimator): The Auto collimator is commonly used to measure the flatness of a surface plate. It can precisely measure small angular deviations by using the principle of parallel rays and reflections, which is ideal for measuring flatness.
- Q – 3 (Profile of a cam and Dividing head and dial gauge): A Dividing head and dial gauge is used for measuring the profile of a cam. The dividing head helps in dividing a circle into equal parts and measuring angular displacement while the dial gauge measures the exact profile.
- R – 4 (Alignment error of a machine tool slide way and Optical interferometer): An Optical interferometer is used for measuring very small linear displacements and alignment errors, making it ideal for checking the alignment of machine tool slideways.
- S – 2 (Pitch and angle errors of screw thread and Tool maker’s microscope): The Tool maker’s microscope is used to measure pitch and angle errors of screw threads. It is equipped with high precision optics, making it suitable for detailed measurement of thread profiles. Thus, option (B) is correct.
| Defect in deep drawing cup | Reason | ||
|---|---|---|---|
| P | Orange peel on the surface of cup | 1 | No blank holding force |
| Q | Wrinkling at the flange of cup | 2 | Very small corner radius of the punch |
| R | Tearing at the bottom corner of cup | 3 | Large grain size in the blank material |
| S | Earring at the top edge of the cup | 4 | Anisotropy of the blank material |

