Class 12 - EG - Pre Board 2 Exam

 

St. COLUMBA’S SCHOOL

Ashok Place, N. Delhi – 110001

Pre-Board 2, February 2021

Class XII, Engineering Graphics

Time: 3 hrs                                                                                                      MM : 70

Instructions

1.       Attempt all questions.

2.       All dimensions are in mm.

3.       Follow the SP: 46-1988 codes (with first angle projections)

4.       Use both sides of the drawing sheet, if required.

5.       Missing or mismatching dimensions, if any, may be suitably assumed

6.       Diagrams are not to scale. Follow the dimensions only.

7.       Draw neat projections/ views.

  

Q 1 (a) Construct an Isometric scale of length 80 mm with subdivisions.           (4)                             

 

       (b) Draw isometric projection of a pentagonal pyramid in

             the vertical position having base side 40 mm and having one of the base edges, away 

         from the observer parallel to the VP.                                                   (7)

 

       (c) Draw the isometric projection of a hemisphere of diameter 60 mm

             placed centrally on top of a hexagonal slab (prism) of base side 40 mm

             and height 30 mm.                                                                                         (14)

 

Q 2 (a) Draw to scale 1: 1 the standard profile of knuckle thread of pitch 30 mm.

             Give standard dimensions.                                                                                  (7)

                                                            OR

             Draw to scale 1: 1 the FV and TV of a square nut keeping its axis vertical 

             and having nominal diameter 20 mm. Give standard dimensions.

 

        (b) Sketch freehand FV and TV of a Pan Head Rivet in vertical position

               having diameter of 20 mm. Give standard dimensions.                                    (5)

                                                            OR

              Sketch freehand FV and TV of a plain stud M 20 keeping the axis in the  

              horizontal position. Give standard dimensions.                                                                      

Q 3   Answer the following Multiple Choice Questions (MCQs).    (1 mark each)           (5)                                    

 

1.      Which of the following is a pictorial drawing?

(a)    Orthographic    (b) Isometric        (c) Development  (d) Pantography

2.      The Isometric projection is shorter than Isometric drawing by?

(a)    19.5 %               (b) 81.5 %              (c) 30 %                (d) 18.5%    

3.      The threads that offer least resistance to motion and also used in screw jacks is?

(a)    Metric              (b) BSW                  (c) Knuckle           (d) Square

4.      The angle of chamfering on a nut is?

(a)    10⁰                    (b) 15⁰                     (c) 20⁰                   (d) 30⁰

5.      What is the angle between the main scale and the isometric scale?

(a)    30⁰                    (b) 45⁰                     (c) 15⁰                   (d) 75⁰

 

 

 

Q 4  Fig below shows the parts of a Gib and Cotter joint. Assemble its parts

         correctly and then draw the following views to 1:1 scale. 

                                                                                                                                                  

(a)    Front view upper half in section                                                        (12)

(b)   Top view of the assembly                                                                     (6)

(c)    Left hand side view                                                                                (6)      

           

Print tile, scale used, projection symbol and give all important dimensions    (4)