EMT 3156 Workshop Practice I Past Paper 2020/2021 PDF

MERU UNIVERSITY OF SCIENCE AND TECHNOLOGY P.O. Box 972-60200 – Meru-Kenya Tel: +254(0) 799 529 958, +254(0) 799 529 959, + 254 (0) 712 524 293, Website: [email protected] Email: [email protected] Universi...

MERU UNIVERSITY OF SCIENCE AND TECHNOLOGY P.O. Box 972-60200 – Meru-Kenya Tel: +254(0) 799 529 958, +254(0) 799 529 959, + 254 (0) 712 524 293, Website: [email protected] Email: [email protected] University Examinations 2020/2021 FIRST YEAR SECOND SEMESTER EXAMINATION FOR THE DEGREE OF BACHELOR OF EDUCATION TECHNOLOGY IN ELECTRICAL ENGINEERING EMT 3156: WORKSHOP PRACTICE I DATE: JULY 2021 TIME: 2 HOURS INSTRUCTIONS: Answer question one and any other two questions QUESTION ONE (30 MARKS) a) i. State any four hazards likely to be found in a welding shop (4 marks) ii. Discuss any two gas welding techniques (4 marks) iii. With aid of neat schematic diagram, indicate the main parts and components of electric arc welding process and explain about straight polarity and reverse polarity (2 marks) b) i. State any four objectives of cutting oils in machining (2 marks) ii. What are the safety precautions to be observed when performing the following workshop operations (list four in each) 1. Turning (2 marks) 2. Milling (2 marks) 3. Gas welding (2 marks) 4. Arc welding (2 marks) c) i. Assuming the jaws of the vernier calipers in figure Q1(c) are tightly closed. Find the zero errors in each (8 marks) Meru University of Science & Technology is ISO 9001:2015 Certified Foundation of Innovations Page 1  ii. Enumerate any two processes that can be done on the milling machine (2 marks) QUESTION TWO (15 MARKS) a) i. With neat sketches enumerate any six operations that can be achieved on a lathe (6 marks) ii. Explain any two consumable electrode welding processes in common practice b) The figure Q2(b) shows a component to be turned from diameter 60mm shaft on a lathe machine. Identify any five different operations performed on the workpiece and the tool used (5 marks) QUESTION THREE (15 MARKS) a) i. Outline any four safety precautions observed 1. Before entering workshop (2 marks) 2. After workstation (2 marks) Meru University of Science & Technology is ISO 9001:2015 Certified Foundation of Innovations Page 2  3. When leaving (2 marks) ii. Explain any two filing problems and state how they can be solved (4 marks) b) i. Outline five causes of accidents in workshops (21/2 marks) ii. Enumerate any five operations that can be achieved by drilling machine (21/2 marks) QUESTION FOUR (15 MARKS) a) i. Distinguish between measurements and inspection (2 marks) ii. Name any six common marking out tools used in engineering workshops (3 marks) b) i. Explain two artificial methods of timber seasoning (4 marks) ii. With aid of neat sketches, outline four natural timber defects (4 marks) c) enumerate any two types of fits and clearances (2 marks) QUESTION FIVE (15 MARKS) a) i. Explain the functions of the following gauges 1. Taper gauges (1 mark) 2. Limit gauges (1 mark) 3. Form gauges (1 mark) 4. Thread gauges (1 mark) ii.Which are the four types of datums commonly used in measurements and marking out (4 marks) b) A 5mm thick sheet of 20mm width is to be bent into an angle of 900 so that the two sides of angle are 50mm as shown in figure Q(b). determine the total length of sheet material and maximum bending force required (7 marks) (Take E=200Kn/mm2. Yield tensile stress δ y = 350 N / m 2 , strain hardening rate, n=500N/mm2 & µ = 0.1) Meru University of Science & Technology is ISO 9001:2015 Certified Foundation of Innovations Page 3 Meru University of Science & Technology is ISO 9001:2015 Certified Foundation of Innovations Page 4