5.1 State TWO advantages of cutting a taper on a lathe machine by using the compound slide method. 5.2 FIGURE 5.2 below shows a taper with an included angle of 8°. Answer the questions that follow. Calculate the following: 5.2.1 The length of the taper 5.2.2 The set-over of the tailstock required to cut the taper 5.3 Calculate the following dimensions for a parallel key suitable for a 75 mm diameter shaft that must be used in the driveshaft of a crane: 5.3.1 Width 5.3.2 Thickness 5.3.3 Length 5.4 State TWO disadvantages of down-cut milling.

NSC Mechanical Technology Fitting and Machining Lathe function and purpose: 5.1 State TWO advantages of cutt

5.1 State TWO advantages of cutting a taper on a lathe machine by using the compound slide method - NSC Mechanical Technology Fitting and Machining - Question 5 - 2021 - Paper 1

Question 5

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5.1 State TWO advantages of cutting a taper on a lathe machine by using the compound slide method. 5.2 FIGURE 5.2 below shows a taper with an included angle of 8°. ... show full transcript

Worked Solution & Example Answer:5.1 State TWO advantages of cutting a taper on a lathe machine by using the compound slide method - NSC Mechanical Technology Fitting and Machining - Question 5 - 2021 - Paper 1

Step 1

State TWO advantages of cutting a taper on a lathe machine by using the compound slide method.

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Answer

Tapers with large angles can be cut effectively, facilitating diverse machining tasks.
The setup is straightforward, making it user-friendly and time-efficient.

Step 2

The length of the taper

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Answer

To calculate the length of the taper ( $l$ ), we use the tangent of half the angle:

an rac{ heta}{2} = rac{D - d}{2 imes l}

Substituting the known values:

2l = rac{92 - 50}{ an(4°)} \ 2l = rac{42}{0.069926818} \ l = rac{600.627909}{2} \ l = 300.31 ext{ mm}

Therefore, the length of the taper is approximately 300.31 mm.

Step 3

The set-over of the tailstock required to cut the taper

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Answer

The set-over can be calculated using:

ext{Set-over} = rac{L(D - d)}{2} \ ext{Set-over} = rac{425.31 imes (92 - 50)}{2 imes 300.31} \ ext{Set-over} = rac{425.31 imes 42}{600.62} \ ext{Set-over} = 29.74 ext{ mm}

Thus, the set-over of the tailstock required is approximately 29.74 mm.

Step 4

Width

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Answer

To find the width of the parallel key suitable for a 75 mm diameter shaft:

ext{Width} = rac{D}{4} \ ext{Width} = rac{75}{4} \ ext{Width} = 18.75 ext{ mm}

Hence, the width is 18.75 mm.

Step 5

Thickness

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To determine the thickness:

ext{Thickness} = rac{D}{6} \ ext{Thickness} = rac{75}{6} \ ext{Thickness} = 12.50 ext{ mm}

Therefore, the thickness is 12.50 mm.

Step 6

Length

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Answer

For the length of the parallel key:

ext{Length} = 1.5 imes ext{diameter of shaft} \ ext{Length} = 1.5 imes 75 \ ext{Length} = 112.50 ext{ mm}

Thus, the length is 112.50 mm.

Step 7

State TWO disadvantages of down-cut milling.

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Answer

Vibration in the arbor is unavoidable which can affect the quality of the cut.
A fine feed must be used; otherwise, the cutting edges may be damaged by contact with hard scale.

5.1 State TWO advantages of cutting a taper on a lathe machine by using the compound slide method - NSC Mechanical Technology Fitting and Machining - Question 5 - 2021 - Paper 1

Worked Solution & Example Answer:5.1 State TWO advantages of cutting a taper on a lathe machine by using the compound slide method - NSC Mechanical Technology Fitting and Machining - Question 5 - 2021 - Paper 1

State TWO advantages of cutting a taper on a lathe machine by using the compound slide method.

The length of the taper

The set-over of the tailstock required to cut the taper

Width

Thickness

Length

State TWO disadvantages of down-cut milling.

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