This set of Machine Drawing Quiz focuses on “Convention in Sectioning & Section Lines Hatching”.
1. Cutting plane is shown by _______ with thick end and two arrows in the direction view.
a) section line
b) chain line
c) single line
d) double line
Explanation: Cutting plane is shown by chain line with thick end and two arrows in the direction view. Cutting plane is named by identification letters such as A-A, X-X, Y-Y, etc. Cutting plane is that which cut the section plane at suitable angle for viewing internal dimensions.
2. In assembly half section, the section line cut the plane at an angle _________ or ________
a) 35, 45
b) 45, 125
c) 35, 135
d) 45, 135
Explanation: In assembly half section, solid area cut by the cutting plane is shown by thin section lines at 45° or 135°, if material is iron. Means the section cut the plane at an angle 45° or 135°. This angle is also used for the hatching line which is used in section planes when the two objects are adjacent.
3. If some important details are in the view it is sown by the ______ line.
a) section line
b) chain line
c) dashed line
d) double line
Explanation: If some important details are required, then dashed lines can be used. Hidden edges are generally not shown if they come in sectional view and should be avoided as far as possible. Because showing both the lines the sectional view is confusing for understanding.
4. Thin parts like stiffeners, webs, bolts, rivets, etc. are ________ if they are cut by the cutting plane along their axis.
a) not hatched
d) not sectioned
Explanation: Thin parts like stiffeners, bolts, rivets, webs, etc. are not hatched if they are cut by the cutting plane along their axis. But it is shown by hatched if the cutting plane cuts at right angles to the axis. These parts are never shown with section lines.
5. ________ are not hatched but darkened like solids.
a) Very thin parts
b) Thin parts
c) Thick parts
d) Single part
Explanation: Very thin parts are not hatched but darkened like solids. For small parts, the gap is reduced, and for big parts, the section lines are drawn at a greater distance. For very large areas, section lines are drawn at near the boundary surface up to a certain length and central portion is left unhatched.
6. Long parts that cannot be accommodated on the drawing sheet are ____________
a) Shown continuous
b) Shown partly brake and partly continuous
c) Shown broken
d) Shown by reducing its scale
Explanation: Long parts that cannot be accommodated on the drawing sheet are shown broken with the cross section conventions. Means, the drawing which is not completely fitted within the sheet is shown by cross section conventions.
7. The crests of the thread are shown by a ______ continuous line and roots by ______ continuous line.
a) thin, thick
b) thick, thin
c) single, thin
d) double, thick
Explanation: The crests of the thread are shown by a thick continuous line and roots by thin continuous line. Because it is correct as by the appearance or viewing. Also, it is easy for understanding and details and properties of drawing.
8. The gap between crest and root lines should not be less than ______ the thickness of thick line.
Explanation: The gap between crest and root lines is kept equal to the depth of the thread. It should not be less than twice the thickness of thick line or 0.7 mm whichever is bigger. For hidden screw threads, the crests and roots are shown by dashed line.
9. Incomplete thread is hatches in assembly of external and internal thread.
Explanation: Incomplete threads are not hatches in assembly of external and internal thread; the area common to both is shown hatched at an angle of external thread. Because the not hatching sows the threads are incomplete in nature according to that view incomplete threads are not hatches in assembly of an external and internal thread.
10. Whatever material is cut by the cutting plane, should be _______
a) not hatched
Explanation: Whatever material is cut by the cutting plane should be hatched. If material is other than iron, standard conventions for some commonly used materials are being used. Like aluminum material showing by the inclined lines and this is placed at too far distance.
11. The hatching line should be inclined at an angle ________
Explanation: The hatching lines are parallel to each other and it is normally inclined at an angle 45° or 135°.If the object is inclined to the horizontal. The hatching angle is to be measured from the objects horizontal axis and inclined at an angle 45° or 135°.
12. When two different parts are adjacent to each other, then the section line is drawn at an angle _____ and _______
a) 35° and 125°
b) 45° and 135°
c) 45° and 125°
d) 35° and 135°
Explanation: When two different parts are adjacent to each other, then the section line is drawn at an angle 45° and 135°. If one part is hatched at an angle 45° then the second object section line drawn at an angle 135° from horizontal. Due to this section line shows the two different objects. It is easy for understanding that it has two separate objects.
13. For three parts are placed in which of the case is fitted for that ___________
a) Change angle of hatching for third part as 45° or 75°
b) The gap between the section lines for object is same for the entire object
c) There will be no offset for the section line
d) The gap between the section lines for object is not same for the entire object
Explanation: When the three objects is placed adjacent to each other following point is to be noted
1 – Change angle of hatching for third part as 30° or 60°.
2 – Offset the lines keeping the angle as 45° or 135°.
3 – Change the gap between the lines relative to the two objects.
The angle of section lines at 45° is to be kept with reference to the axis of the object.
14. The distance between two section lines is called ________
a) length of the section line
b) width of the section line
c) thickness of the section line
d) pitch of the section line
Explanation: The distance between two section lines is pitch of the section line. There is no fixed point or distance at which the section line is draw. It is generally in between the 1 to 3 mm is depending upon the size of the object. Pitch of section lines is one of the most important topics in section lines.
15. The method which suggests the draw the section lines at equal distances is called _________
a) distance of section lines
b) drawing section lines
c) pitch of section lines
d) angle of section lines
Explanation: For better appearance, the section lines are drawn at a proper distance. The method which suggests the draw the section lines at equal distances is called drawing section lines. The section line is drawn with the help of set square and T- square and draws a section line at 45° or 135°.
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