Class 11 Automotive Service Technician Chapter 2 Fasteners

Class 11 Automotive Service Technician Chapter 2 Fasteners Solutions English Medium As Per AHSEC New Syllabus to each chapter is provided in the list so that you can easily browse through different chapters Class 11 Automotive Service Technician Chapter 2 Fasteners Question Answer and select need one. Class 11 Automotive Service Technician Chapter 2 Fasteners Notes Download PDF. AHSEC Class 11 Automotive Service Technician Question Answer English Medium.

Class 11 Automotive Service Technician Chapter 2 Fasteners

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Fasteners

Chapter: 2

SESSION 1: AUTOMOTIVE BOLTS AND MACHINE SCREWS

Check Your Progress

A. Fill in the blanks: 

1. A fastener is a hardware __________ that mechanically joins or __________ two or more objects together. 

Ans: Device, Affixes.

2. Automotive fasteners are made up of a variety of _____________. 

Ans: Stainless steel.

3. A bolt is an externally threaded _________. 

Ans: Fastener.

4. External threads are on the __________ or screws and internal threads are on the __________. 

Ans: Studs, bolts.

5. In India we use ISO __________ thread.

Ans: Metric.

B. Multiple choice questions:

1. Which automotive fastener(s) is (are) used for holding or connecting two or more objects in a machine?

(a) Nuts and bolts.

(b) Wooden keel.

(c) Fibre joint. 

(d) None of the above.

Ans: (a) Nuts and bolts.

2. What is the simple effective diameter of a screw thread? 

(a) Pitch diameter. 

(b) Flank. 

(c) Root. 

(d) Threaded angle.

Ans: (a) Pitch diameter. 

3. What are the straight sides, which connect the crest and the root called? 

(a) Flank.

(b) Root. 

(c) Minor diameter. 

(d) Pitch diameter. 

Ans: (a) Flank. 

 4. Match the following:

Ans: (a) Eye bolt – Image 3

(b) Flange bolt – Image 1

(c) Frame bolt – Image 2

(d) Hanger bolt – Image 4

5. Choose sheet metal screw on the basis of the head shape shown here.

Ans: (c) 

C. Answer the following questions:

1. Describe the importance of bolts.

Ans: Automotive bolts and machine screws are also known as threaded fasteners. They are effective at joining multiple objects. Fasteners have a threaded pin or rod with a head at one end. An automotive bolt is inserted through holes in the assembled parts and fixed firmly with a mated nut with the help of a torque. The bolt and nut are tightened by holding the bolt head stationary and turning the nut for tightening. 

 2. What are machine screws?

Ans: A machine screw is an outside threaded fastener. On the top of a screw is a head, which is used to drive the screw into the object. An automotive bolt with a common head can work as a screw, and can be driven into a hole by the head. Usually, the machine screws are fully threaded.

3. What is the importance of threads on bolt and machine screws?

Ans: A bolt thread is a ridge of uniform section in the form of a helix on either the external or internal surface of the cylinder. Internal threads refer to those on nuts and tapped holes and external threads are those on bolts, studs, or screws. The helix of a thread can twist in two possible directions — right hand (RH) or left hand (LH).

4. Differentiate between bolt and screw.

Ans: The differences between bolt and screw are as under:

Bolt	Screw
An automotive bolt is inserted through holes in the assembled parts and fixed firmly with a mated nut with the help of a torque.	A machine screw is an outside threaded fastener. On the top of a screw is a head, which is used to drive the screw into the object.
The bolt and nut are tightened by holding the bolt head stationary and turning the nut for tightening.	An automotive bolt with a common head can work as a screw and can be driven into a hole by the head.
Bolt has external threads, typically paired with a nut.	Screw is an outside threaded fastener, usually fully threaded
The bolt head is used to secure the bolt when tightening with a nut.	The screw head is used to drive the screw into the object.

5. What do you understand by metric thread? Make a profile of metric thread and state all the terminologies.

Ans: A metric thread is defined by its profile and it follows the ISO standards. The basic profile of an ISO metric thread includes the following parameters:

(i) D = Major diameter of internal thread (nut).

(ii) d = Major diameter of external thread (bolt).

(iii) D2 = Pitch diameter of internal thread.

(iv) d2 = Pitch diameter of external thread.

(v) D1 = Minor diameter of internal thread.

(vi) d1 = Minor diameter of external thread.

(vii) P = Pitch.

(viii) H = Height of fundamental triangle.

(ix) d = D = nominal diameter.

(x) d1 = D1 = d – 1.0825 P.

(xi) d2 = D2 = d – 0.6495 P.

(xii) P = Pitch.

(xiii) H = 0.866 P.

(xiv) r = 0.1443 P.

SESSION 2: AUTOMOTIVE NUTS

Check Your Progress

A. Fill in the blanks: 

1. A nut is a type of fastener with a _____________ hole. 

Ans: Threaded.

2. For joining two metal parts, the nut is screwed onto the _____________. 

Ans: Bolt.

3. The _____________ of the bolt and nut must be same else the nut cannot be _____________ on the bolt. 

Ans: Pitch, screwed.

4. A nut can have left hand or right hand _______________ threads. 

Ans: Internal.

5. A hexagonal nut is a type of metal fastener that has _____________ sides.

Ans: Six.

B. Multiple choice questions:

1. Which factor of the bolt and nut must be the same for the nut to be screwed on the bolt? 

(a) Pitch.

(b) Minor diameter.

(c) Root.

(d) Flank.

Ans: (a) Pitch.

2. Which of the following is a hexagonal nut?

Ans: (a) 

3. Which nut is used to join two externally threaded rods together? 

(a) Coupling. 

(b) K-lock or Kep. 

(c) Square. 

(d) None of the above.

Ans: (a) Coupling. 

4. Which nut is used specifically in automotive bearing or wheel hub to spindle assemblies? 

(a) Slotted Hex Nuts.

(b) Prevailing torque lock.

(c) K-lock or Kep. 

(d) Square.

Ans: (a) Slotted Hex Nuts.

SESSION 3: AUTOMOTIVE STUDS

Check Your Progress

SESSION 4: AUTOMOTIVE WASHERS AND RIVERS

Check Your Progress

SESSION 5: REMOVAL AND REPLACEMENT OR DAMAGED FASTENERS

Check Your Progress