1. Which of the following grade is never used for fits?
a) H10
b) H11
c) H8
d) H9
Explanation: H5, H6, H7, H8, H9, H10, H11 these are the hole grades. H10 is not used for diameter fits. It can be used for milled widths. H11 is never used for fits because this grade is very coarse. H11 is useful only for coarse punched holes or drilled holes.
2. Which of the option is correct about the preference of shaft and holes in machine tool industries?
a) ‘A11’ is of first preference in shafts
b) ‘B9’ is of first preference in holes
c) ‘c2’ is of first preference in shafts
d) ‘b11’ is of second preference in holes
Explanation: a11, c2, d9, d11, e8 etc. are the first preference for shafts and b9, b11, c8, c11, d8 etc. are the second preferences for shafts. First preference of holes are A11, D11, E11, F7, F8 etc. and B9, B11, C9, C11, D9 etc. are the second preferences for holes.
3. Which of the following option is correct for given statements regarding the selection of fits?
Statement 1: Shaft ‘h’ is an interference fit and used only for running parts.
Statement 2: Shaft ‘k’ is the true transition fit.
a) T, F
b) F, F
c) T, T
d) F, T
Explanation: Shaft ‘h’ gives clearance fit and available in grades 5 to 11. It is useful for spigot fits. Shaft ‘k’ is a transition fit and it is best suited for location fits. Grades available for this category are also 5 to 11.
4. Which shaft is used in valve shaftings?
a) Shaft ‘s’
b) Shaft ‘f’
c) Shaft ‘b’
d) Shaft ‘t’
Explanation: Shaft ‘s’ gives interference fit. It is used for semi-permanent or permanent assemblies of cast iron and steel members. It can be used for valve shafting’s and collar pressed on the shaft.
5. Which of the following gives interference fit?
a) Shaft ‘n’
b) Shaft ‘p’
c) Shaft ‘m’
d) Shaft ‘g’
Explanation: Shaft ‘p’ gives a true interference fit and available in grades 6 or 7. With hole of grade 8 it behaves as transition fit. It is a standard fit for cast iron and steel. It can be used for fixing of a bush on a gear. Shaft ‘g’ gives clearance fit. Shaft ‘m’ and ‘n’ gives transition fit.
6. Which of the following is not correct about plain gauges?
a) Used to check threaded portions
b) There is no scale in plain gauges
c) Indicates actual value of the inspected dimension
d) Can be used to check dimension of manufactured part
Explanation: These gauges do not have any scale. These gauges are used only for determining that the inspected part is within a specified limit or not. They do not use to indicate actual value. Plain gauges are mostly used to check unthreaded shafts and holes.
7. What of the following option correctly define a solid gauge?
a) Gauging portion and handle separately manufactured
b) Gauge integral with the handle
c) Gauges with suitable locking devices
d) Gauges that are not used for cylindrical holes
Explanation: When the whole gauge is made from one single piece of metal or gauging portion is integral with the handle, such type of gauges are called solid gauges. Gauging portion and handle of ‘renewable type of gauge’ is separately manufactured.
8. What is the hardness of gauging portion in plain plug gauges?
a) 450 HV
b) 550 HV
c) 650 HV
d) 750 HV
Explanation: Gauging surfaces of plain plug gauges are suitably stabilized, lapped and ground. These surfaces are normally hardened to not less than 750 HV. For sizes up to 63 mm, double ended type of plug gauges are used, and for above 63 mm single ended are used.
9. Which of the following is not true for fixed gauges?
a) Independent of availability of power supply
b) These are not expensive
c) Chances of human errors are more
d) Provide uniform reference standard
Explanation: Fixed gauges are generally error free due to drift of the original adjustment, effect of variation of power, non-linear response etc. Human errors are almost nil except for careful handling. Auxiliary equipment and setups are not required.
10. Up to which diameter, bar type plug gauges are used?
a) 20 mm
b) 40 mm
c) 75 mm
d) More than 75 mm
Explanation: Plain plug gauges which are heavy or diameter more than 75 mm, it is common to use bar type or segmental gauges in this case. Gauge efficiency decrease if sensitiveness of user is impaired by weight.