Question 1 |

A 76.2 mm gauge block is used under one end of a 254 mm sine bar with roll diameter of 25.4 mm. The height of gauge blocks required at the other end of the sine bar to measure an angle of 30^{\circ} is __________mm (round off to two decimal places).

203.2 | |

145.6 | |

214.3 | |

542.6 |

Question 1 Explanation:

\begin{aligned} \sin 30^{\circ} &=\frac{h_{1}}{254} \\ \text{or}\qquad h_{1} &=254 \sin 30^{\circ}=127 \mathrm{~mm} \\ H_{2} &=76.2+127=203.2 \mathrm{~mm} \end{aligned}\\ Case II:

\begin{aligned} \sin 30^{\circ} &=\frac{76.2-h_{1}}{254} \\ \text{or}\qquad h_{1} &=76.2-254 \sin 30^{\circ}\\ &=-50.8 \mathrm{~mm} \end{aligned}

Which is not feasible

Therefore final answer 203.2 mm.

Question 2 |

The allowance provided in between a hole and a shaft is calculated from the difference between

lower limit of the shaft and the upper limit of the hole | |

upper limit of the shaft and the upper limit of the hole | |

upper limit of the shaft and the lower limit of the hole | |

lower limit of the shaft and the lower limit of the hole |

Question 2 Explanation:

It is minimum clearance or maximum interference. It is the intentional difference between the basic dimensions of the mating parts. The allowance may be positive or negative.

Question 3 |

Two smooth identical spheres each of radius 125 mm and weight 100 N rest in a horizontal channel having vertical walls. The distance between vertical walls of the channel is 400 mm.

The reaction at the point of contact between two spheres is _______N (round off to one decimal place).

The reaction at the point of contact between two spheres is _______N (round off to one decimal place).

110 | |

125 | |

258 | |

324 |

Question 3 Explanation:

\begin{aligned} B C &=250^{2}-150^{2} \\ \cos \theta &=\frac{200}{250} \\ \theta &=36.869^{\circ} \end{aligned}

\begin{aligned} R_{2} \cos \theta &=100 \\ R_{2} &=\frac{100 \times 250}{200}=125 \mathrm{~N} \end{aligned}

Question 4 |

Consider the surface roughness profile as shown in the figure.

The center line average roughness (R_a \text{ in }\mu m) of the measured length (L) is

The center line average roughness (R_a \text{ in }\mu m) of the measured length (L) is

0 | |

1 | |

2 | |

4 |

Question 4 Explanation:

R_{G}=\frac{\sum_{i=1}^{n} y}{n}=\frac{4}{4}=1

Question 5 |

Two rollers of diameters D_1 (in mm) and D_2 (in mm) are used to measure the internal
taper angle in the V-groove of a machined component. The heights H_1 (in mm) and H_2
(in mm) are measured by using a height gauge after inserting the rollers into the same
V-groove as shown in the figure.

Which one of the following is the correct relationship to evaluate the angle \alpha as shown in the figure?

Which one of the following is the correct relationship to evaluate the angle \alpha as shown in the figure?

\sin \alpha =\frac{(D_1-D_2)}{2(H_1-H_2)-(D_1-D_2)} | |

\cos \alpha =\frac{(D_1-D_2)}{2(H_1-H_2)-2(D_1-D_2)} | |

cosec\; \alpha =\frac{(H_1-H_2)-(D_1-D_2)}{2(D_1-D_2)} | |

\sin \alpha =\frac{(H_1-H_2)}{(D_1-D_2)} |

Question 5 Explanation:

\begin{aligned} O B &=\left(H_{1}-\frac{D_{1}}{2}\right)-\left(H_{2}-\frac{D_{2}}{2}\right)\\ &=\left(H_{1}-H_{2}\right)-\left(\frac{D_{1}-D_{2}}{2}\right) \\ O A &=\frac{D_{1}-D_{2}}{2} \\ \sin \alpha &=\frac{\frac{\left(D_{1}-D_{2}\right)}{2}}{\left(H_{1}-H_{2}\right)-\frac{\left(D_{1}-D_{2}\right)}{2}} \\ \sin \alpha &=\frac{\left(D_{1}-D_{2}\right)}{2\left(H_{1}-H_{2}\right)-\left(D_{1}-D_{2}\right)} \end{aligned}

Question 6 |

The figure below shows a symbolic representation of the surface texture in a perpendicular
lay orientation with indicative values (I through VI) marking the various specifications
whose definitions are listed below.

P: Maximum Waviness Height (mm);

Q: Maximum Roughness Height (mm);

R: Minimum Roughness Height (mm);

S: Maximum Waviness Width (mm);

T: Maximum Roughness Width (mm);

U: Roughness Width (mm);

The correct match between the specifications and the symbols (I to VI) is:

P: Maximum Waviness Height (mm);

Q: Maximum Roughness Height (mm);

R: Minimum Roughness Height (mm);

S: Maximum Waviness Width (mm);

T: Maximum Roughness Width (mm);

U: Roughness Width (mm);

The correct match between the specifications and the symbols (I to VI) is:

I-R, II-Q, III-P, IV-S, V-U, VI-T | |

I-R, II-P, III-U, IV-S, V-T, VI-Q | |

I-U, II-S, III-Q, IV-T, V-R, VI-P | |

I-Q, II-U, III-R, IV-T, V-S, VI-P |

Question 6 Explanation:

I-R, II-Q, III-P, IV-S, V-U, VI-T

Question 7 |

The most common limit gage used for inspecting the hole diameter is

Snap gage | |

Ring gage | |

Plug gage | |

Master gage |

Question 7 Explanation:

Plug gauges used for hole & Ring gauge used for shaft

Question 8 |

The height (in mm) for a 125 mm sine bar to measure a taper of 27^{\circ}{32}' on a flat work piece is _______ (correct to three decimal places).

32.247 | |

48.358 | |

57.782 | |

64.124 |

Question 8 Explanation:

(57.782)

\begin{aligned} \theta &=27^{\circ} 32^{\prime} \\ &=27+\left(\frac{32}{60}\right)^{\circ}=27.533^{\circ} \\ \text{In sine bar,}\quad \sin \theta &=\frac{H}{L}\\ \therefore \quad \sin 27.533^{\circ} &=\frac{H}{125} \\ H &=57.782427 \\ H & \approx 57.782 \mathrm{mm} \end{aligned}

\begin{aligned} \theta &=27^{\circ} 32^{\prime} \\ &=27+\left(\frac{32}{60}\right)^{\circ}=27.533^{\circ} \\ \text{In sine bar,}\quad \sin \theta &=\frac{H}{L}\\ \therefore \quad \sin 27.533^{\circ} &=\frac{H}{125} \\ H &=57.782427 \\ H & \approx 57.782 \mathrm{mm} \end{aligned}

Question 9 |

A cylindrical pin of 25_{+0.020}^{+0.010}\,mm diameter is electroplated. Plating thickness is 2.0^{\pm 0.005} mm.Neglecting the gauge tolerance, the diameter (in mm, up to 3 decimal points accuracy) of the GO ring gauge to inspect the plated pin is _______

29.03 | |

25.02 | |

27.03 | |

23.03 |

Question 9 Explanation:

GO ring gauge will inspect maximum metal

conditions i.e. UL of shaft i.e. Largest size after

platting.

UL after platting =25.02+2.005+2.005 \mathrm{mm}= 29.030 \mathrm{mm}

conditions i.e. UL of shaft i.e. Largest size after

platting.

UL after platting =25.02+2.005+2.005 \mathrm{mm}= 29.030 \mathrm{mm}

Question 10 |

Assume that the surface roughness profile is triangular as shown schematically in the figure. If the peak to valley height is 20\,\mu m, The central line average surface roughness R_{a}(in\,\mu m) is

5 | |

6.67 | |

10 | |

20 |

Question 10 Explanation:

R_{a}=\frac{h}{4}=\frac{20}{4}=5 \mu \mathrm{m}

There are 10 questions to complete.