Metal Exam

Question 1

When using the lathe, how much stock can be protruding from the chuck?

Answer 1

No more than twice the diameter.

Question 2

When cutting the face off stock, where do you start and end?

Answer 2

You start cutting from the center to the edge

Question 3

What are the main reasons for knurling a piece of work?

Answer 3

The main reasons are to make a hand grip, improve the appearance of the surface, and increase the diameter of a workpiece.

Question 4

What is the spindle speed formula?

Answer 4

Pie * diameter * RPM / 12

Question 5

What is the formula for calculating spindle RPM?

Answer 5

Cutting speed * 4 / Diameter

Question 6

For lathing, what is the feed rate?

Answer 6

The feed rate is how far the tool bit advances with each revolution of the work piece.

Question 7

When making a rough cut on the lathe it requires a ____ _____ ____.

Answer 7

Faster feed rate

Question 8

When making a finishing cut on the lathe it requires a _____ _____ _____.

Answer 8

Slower feed rate

Question 9

For lathing, what is the depth of cut?

Answer 9

How far the tool bit advances into the stock material.

Question 10

What is a common use for parallels?

Answer 10

Parallels are used to space work above the bottom of the vice; parallels are used for precision and close tolerance when milling or drilling stock.

Question 11

There are several angles ground on a lathe tool which provide the necessary shape for efficient cutting. The angles used depend on:

Answer 11

1) The hardness of the material being cut.
2) The rigidity of the lathe.
3) The amount of metal to be removed each cut.
4) The quality of finish required.

Question 12

For a lathe bit, when the tool angle is large (NOT a knife edge), the tool:

Answer 12

1) has maximum strength
2) provides good heat dissipation
3) requires more power to cut

Question 13

For a lathe bit, when the tool angle is smaller (sharper edge), the tool:

Answer 13

1) has a weaker cutting edge
2) machines a good finish
3) gives little tearing
4) cuts easily

Question 14

What is the purpose of a relief angle on a lathe bit?

Answer 14

Relief angles ensure that only the cutting edge contacts the work. If a relief angle is not
correct, the side or end of the tool will rub, preventing the sharp edge from doing its job.

Question 15

What is the purpose of rake angles on a lathe bit?

Answer 15

Rake angles help the material slide away from the work as it is cut off.

Question 16

What is the purpose of side and end cutting angles for lathe bits?

Answer 16

Cutting material; Side and End cutting angles are usually not critical, but allow you to approach the work from
various orientations.

Question 17

What is the angle for a center drill?

Answer 17

60 degrees

Question 18

How is the depth measured when using a center drill?

Answer 18

It is measured to the shoulder.

Question 19

What are all the main components of a drill bit?

Answer 19

Chisel point, cutting edge, flute.

Question 20

What is the typical metal drill angle?

Answer 20

118 degrees.

Question 21

What is the critical temperature when heat-treating steel? And what indicates this temp?

Answer 21

790-830 C is the critical temp, and it is indicated when the steel is a bright cherry color and non-magnetic.

Question 22

In order for steel to be heat-treatable, how much carbon content must it have?

Answer 22

0.65%

Question 23

Steel may be brittle after hardening, what is a method that can strengthen it after hardening?

Answer 23

Tempering to a particular temperature and quenching it again.

Question 24

When tempering knives and chisels, what should the color and temperature be?

Answer 24

Dark blue; 300 C

Question 25

When tempering axes, wood chisels, and tools, what should the color and temperature be?

Answer 25

Purple; 270 C

Question 26

When tempering sheer blades and hammer faces, what should the color and temperature be?

Answer 26

Dark straw; 254 C

Question 27

When tempering tool bits, drills, and taps, what should the color and temperature be?

Answer 27

Faint straw; 220 C

Question 28

What is a good work-holding tool that can help drill round stock horizontally and vertically?

Answer 28

A V-block

Question 29

When drilling holes across the diameter of round stock, what is used to help prevent the drill bit from wandering?

Answer 29

A drill bushing

Question 30

What material does a C-clamp work best with when work holding?

Answer 30

Flat bar, sheet stock, or plate

Question 31

When your work piece has only one flat or square face, what can be used to secure it in a vice?

Answer 31

Put a piece of round stock (softer than your work) between your work and the jaw of the vice.

Question 32

What is the feed rate for knurling?

Answer 32

.015 to .030 for coarse and .010 to .015 for fine.

Question 33

What style of chuck jaw is used for wider-diameter stock?

Answer 33

Outside jaws

Question 34

What style of chuck jaws grip on the inside and outside?

Answer 34

Inside jaws

Question 35

What style of chuck jaws is least accurate on the lathe?

Answer 35

The 3 jaw chuck

Question 36

Review all the major lathe components and lathe bit parts on James’ slides.

Question 37

When using a lathe, what is the recommended cutting speed for mild steel?

Answer 37

90 for a rough cut and 100 for a finish cut.

Question 38

When using a lathe, what is the recommended cutting speed for tool steel?

Answer 38

70 for a rough cut and 90 for a finish cut.

Question 39

When using a lathe, what is the recommended cutting speed for Aluminum?

Answer 39

200 for a rough cut and 300 for a finish cut.