Experiment 4 2y6u19

Metrology and Quality Control

Experiment No. 4

Experiment No. 4 1.0

TITLE: To find unknown angle of a given component using sine bar.

2.0

PRIOR CONCEPT: 1. 2. 3. 4.

3.0

Knowledge of trigonometric relations Use of bevel protractor Use of slip gauges Use of dial indicator

NEW CONCEPT: Proposition: Sine bar is used to measure the unknown angle of workpiece with the help of slip gauges and dial indicator. Concept structure: -

4.0

LEARNING OBJECTIVES: At the end experiment, the student will acquire the following skills.

4.1 Intellectual skill:

Understand the use of Sine bar in setting a work piece to a known / given angle. Calculate unknown angle using sine bar.

4.2 Motor skills:

5.0

Ability to use of sine bar along with slip gauges and dial indicator. Use of dial indicator to check parallelism.

APPARATUS: The experiment requires following equipments: 1. Sine bar, height gauge 2. Surface plate, Set of Standard slip gauges, dial indicator with stand 3. Component whose unknown angle is to be measured

6.0

DIAGRAM:

Fig 4.1 SINE BAR

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♦ 17

Experiment No. 4

Metrology and Quality Control

Fig 4.2 CHECKING OF UNKNOWN ANGLE WITH THE HELP OF SINE BAR

Fig 4.3 CHECKING OF UNKNOWN ANGLE OF HEAVY COMPONENT

7.0

PROCEDURE: 7.1 Brief theory: Sine bar is always used in conjunction with datum (e.g. surface plate) and auxiliary equipments such as slip gauges, dial indicator, angle plate and height gauge. It consists of a steel bar containing two rollers of equal diameter attached at the end of it as shown in fig. The axes of these two rollers are mutually parallel to each other and are also parallel to and at equal distance from the upper surface of sine bar. The distance between the axes of roller known as length of sine bar is usually 100mm, 200mm & 300mm. Some holes are drilled in the body of the bar to reduce the weight and to facilitate the handling as shown in fig.4.1 It is made up of high carbon, high chromium, corrosion resistance steel, hardened ground & stabilized steel. 7.2

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Stepwise Procedure: 1. Note the length of sine bar L =……….mm 2. Find the approximate angle of the component by using bevel protractor or any other suitable device. Let this angle be θ. 3. Calculate the height of slip gauges (h) required from relation Sin θ = h/L, where L is the length of sine bar. h = L sin θ 4. Select & wring together the required slip gauges for dimension ‘h’ mm. 5. Place the work piece on sine bar & clamp to the angle plate if necessary as shown.

MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION

Metrology and Quality Control

6. 7. 8. 9. 10. 11.

Experiment No. 4

Dial indicator is clamped firmly in dial indicator stand and slight pressure applied so that plunger just touches one end of workpiece. To check the parallelism of upper surface of workpiece, a dial indicator along with the stand is moved from one end of the work and moved to other end. Note the deviation ‘δh’. This deviation may be noticed by taking two readings of dial indicator at two ends of work piece top edge. Add / subtract the slip gauges of height ‘dh’. Where dh = δh *L/l ‘l’ is length of workpiece. Adjust the slip gauges so that deviation of dial indicator is zero from one end to other end. Calculate the height of slip gauges. Unknown angle = sin–1(Height of slip gauges/Length of sine bar) = sin-1(h/L) = —————— = ———————

Precaution & Care: 1. Sine bar should not be used for the angles more than 45 degree.

8.0

QUESTIONS: - (Attempt 3-5 questions as directed by teacher) 1. 2. 3. 4. 5. 6.

Name two industrial jobs whose taper angle can be measured by sine bar. Why relief holes are provided on sine bar? What are the limitations of sine bar? State the specifications of sine bar. What is sine center? Explain how a sine bar may be employed to determine the angle of a taper plug gauge. (Space for answer)

MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION

♦ 19

Experiment No. 4

Metrology and Quality Control

(Space for answer)

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MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION