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Questions and Answers

Which of the following types of portable fire extinguishers is classified as the best type of extinguisher to use on a paper fire?

A) Class A (correct)

B) Class B

C) Class C

D) Class D

Which of the following best describes a narrow rule?

It is most commonly used by Machinists

It has graduations only along one edge. (correct)

It can be used to set an inside caliper

It has measuring edges ground flat

With machine screws, which of the following has the largest major diameter?

#2 (correct)

With file coarseness, when does the distance between the teeth becomes narrower?

It becomes narrower as the length of the file decreases Signup and view all the answers

Using the Unified thread designation, a bolt has the following:

1/2-16 UNC- 2A

What does the "2" on the above designation represent?

It represents the thread class Signup and view all the answers

How many teeth per inch should a hacksaw have if it is used to cut tool steel?

18 Signup and view all the answers

Which of the following best describes a three square file?

Triangular in section with shaper corners and are used to produce sharp 90 degree shoulders Signup and view all the answers

What kind of sling does this best represent?

It represents a double eye sling. Signup and view all the answers

The three types of harmful rays encountered during oxyacetylene use are visible light rays, infrared rays and what other rays?

And ultraviolet rays Signup and view all the answers

About what percentage of the backing material is covered by abrasive on an open coated abrasive?

About 50 to 70% Signup and view all the answers

To safeguard the wire rope from breaking during use, what would most likely be the safety factor used for public elevator cables?

20:1 Signup and view all the answers

Which of the following terms describes discrimination?

The smallest division on a scale that can be read reliably. Signup and view all the answers

Which part on a hand-held tap provide a spot for chips to accumulate and a passage for cutting fluid?

The flute Signup and view all the answers

What is parallax error?

A visual error Signup and view all the answers

What is the tap drill size for a M10 1.25 thread?

8.75 mm Signup and view all the answers

What is the best blade to use when cutting cast iron with a hacksaw

The best saw blade to use would be an all-hard blade. Signup and view all the answers

What is a hacksaw's kerf?

The width of cut in the work material Signup and view all the answers

What does a 6 inch caliper mean?

It means that the caliper has 6 inch legs. Signup and view all the answers

Which type of wheel would be used on a grinder when you want to clean a work piece of scale and dirt but not remove any of the metal?

A wire wheel. Signup and view all the answers

In the surface speed formula used with CNC turning machines, as the rpm increases what happens to the CS?

It increases. Signup and view all the answers

How can chattering be reduced when parting off a workpiece?

By reducing the spindle speed. Signup and view all the answers

Which of the following provides a quick way of making an accurate hole with a good surface finish?

reaming Signup and view all the answers

What measurement must be used for a CNC lathe when doing a tapping operation?

RPM Signup and view all the answers

Which of the following describes a stop shaft?

It is set up under the carriage to disengage the feed lever. Signup and view all the answers

What is one of the hazards of applying too much pressure to the fasteners of components when machining?

The component may become deformed. Signup and view all the answers

What is the recommended cutting speed SFPM for high speed steel drills when the workpiece material is Aluminium?

300 Signup and view all the answers

In a CNC program, what does the G code G20 specify?

It specifies that all information must be in the imperial measurement system. Signup and view all the answers

Which of the following is an important characteristic of a good quality cutting fluid?

All of the above. Signup and view all the answers

What is the advantage of a side wheel grinder over a bench grinder?

The advantage is that the grinding surface is flat and the work rest to grinding wheel angle does not change. Signup and view all the answers

Which of the following best describes a sensitive drill press?

It is usually driven by a V-belt. Signup and view all the answers

What is the primary axis on a lathe?

The X and Z axes. Signup and view all the answers

Which of the following is a way to counter the effect of backlash?

All of the above will work. Signup and view all the answers

Where are back rake angles ground?

They are ground on the face of the cutting tool Signup and view all the answers

Which of the following types of abrasive grit is commonly used when grinding steel?

Aluminium oxide Signup and view all the answers

With respect to CNC turning centres which of the following is true with respect to single spindle-single turret arrangements?

It is the most common arrangement. Signup and view all the answers

What does a band file consist of?

It consists of a series of short files riveted to a steel band Signup and view all the answers

What is an axis?

An imaginary line that helps define a coordinate system. Signup and view all the answers

With EIA coding, what is the maximum number of rows where program characters are found?

7 Signup and view all the answers

In a CNC program, what does the M code M05 cause to happen?

It will stop the spindle's rotation. Signup and view all the answers

In a CNC program, what does the M code M00 cause to happen?

It will cause the machine to stop executing a program. Signup and view all the answers

What do Jacob's impact keyless chucks use to align and secure the straight shank?

They use rubber collets. Signup and view all the answers

What diameter must be used when doing spindle calculations for threading operations with a CNC machine?

The major diameter of the thread being cut. Signup and view all the answers

When using a CNC machine there are two linear axes X and Y. Which one is the length controlling motion direction?

Z axes Signup and view all the answers

Which of the following best describes the spindle speed control of a CNC machine?

Its function is to develop appropriate signals from program data for driving servo motors. Signup and view all the answers

What is the advantage of using an oil mist lubrication system?

The advantage is that it ensures the oil is always clean. Signup and view all the answers

What is the cutting speed for a 4-inch diameter workpiece when the RPM is 900?

942.48 RPM. Signup and view all the answers

What is the cutting speed for a 3-inch diameter workpiece when the RPM is 550?

431.97 RPM. Signup and view all the answers

What kind of viscosity does a liquid that pours slowly have?

High Signup and view all the answers

Which of the following is a true with respect to American Standards for Coded Information Interchange?

It uses an even parity format. Signup and view all the answers

Which of the following describes a spider?

It is used when long tubular work pieces require a centre. Signup and view all the answers

With a lathe, where is the headstock is always attached to?

It is attached to the left side of the bed Signup and view all the answers

What is machining of curved surfaces known as?

Undercutting Signup and view all the answers

When referring to a band saw blade, what provides the clearance for the back of the blade?

The set of the blade Signup and view all the answers

Which type of wheel would be used on a grinder when you are doing light finishing and chamfering?

A sanding wheel. Signup and view all the answers

Which of the following cutting fluids would be best to use when drilling into Brass?

A soluble oil. Signup and view all the answers

Which of the following types of shoulders is a simple cut but will weaken the shaft by creating a stress?

The square shoulder. Signup and view all the answers

What type of lubrication system allows lubricant to escape into the environment after it has been applied to the machine?

A flow through system. Signup and view all the answers

How can chattering be reduced when cutting a groove into a workpiece?

By doing all of the above. Signup and view all the answers

With CNC turning centres and lathes, what does the term "parting-off" refer to?

Machining the ends of a workpiece. Signup and view all the answers

What is the recommended drill point angle for hard materials?

150 Signup and view all the answers

Which of the following would be best suited for drilling in very large work pieces that are difficult to position?

A radial drill machine. Signup and view all the answers

Where is the feed reverse lever found on a lathe?

It is found on the headstock Signup and view all the answers

What is the drill point angle for general purpose use?

118 Signup and view all the answers

When is running a dial indicator along a workpiece a good way to align the workpiece?

When the carriage is between the headstock and the steady rest. Signup and view all the answers

Which of the following lathe stops is clamped to the ways of the lathe?

The block stop Signup and view all the answers

What is a characteristic of a Chucking Centre machine?

It is built without a tailstock and has a short centre distance. Signup and view all the answers

The tool rest on a bench grinder should be adjusted so that there is no more than how much of an inch between the grinding wheel and the rest?

No more than 1/8 of an inch Signup and view all the answers

What determines the amount of material that can be removed within a given time with a lathe?

The horsepower of the motor Signup and view all the answers

When programming a CNC what does the letter "T" stand for?

It stands for tool index. Signup and view all the answers

What is the advantage of using a taper attachment over a compound rest for cutting tapers?

Easy transformation of the lathe from taper turning to parallel turning. Signup and view all the answers

On a lathe, where does the compound rest?

It rests on top of the cross-slide Signup and view all the answers

Which of the following best describes a part and grooving tool?

It cuts on its ends Signup and view all the answers

Which of the following is true with respect to NC machines?

They had no memory Signup and view all the answers

Which of the following statements best describes the chisel edge of a drill bit?

It is the portion remaining between the flutes. Signup and view all the answers

What does the term CNC refer to?

Computer Numeric Control. Signup and view all the answers

What does the number 12 represent in the surface speed formula for calculations involving CNC turning machines?

It is used to convert inches to feet. Signup and view all the answers

Which of the following is a disadvantage of a drill chuck

It has poor accuracy Signup and view all the answers

Which of the following best describes a revolving centre?

It rotates on a bearing to prevent friction and heat buildup Signup and view all the answers

What type of CNC work are you performing when you are creating workpieces from raw material that is greater than three times its diameter?

Shaft work Signup and view all the answers

In a CNC program, what does the G code G04 cause to happen?

It causes the machine to pause for a specified period. Signup and view all the answers

When using the front face as program zero, what are all X coordinate values?

They are all positive Signup and view all the answers

Which of the following is a correct statement with respect to Quadrant 3 of an X and Z axis?

-X, -Z Signup and view all the answers

When programming a CNC what does the letter "S" stand for?

It stands for spindle speed. Signup and view all the answers

Which type of lubrication system relies on a pump to force oil under pressure into a bearing?

The enclosed circulating lubrication system Signup and view all the answers

What does the term "grit" refer to when looking at grinding wheels?

It refers to the abrasiveness. Signup and view all the answers

How is an angle denoted with polar coordinates when measured counter clockwise?

Positive Signup and view all the answers

What does odd parity mean in reference to CNC terminology?

Each program character is represented in rows containing odd number holes. Signup and view all the answers

When working with a CNC machine, what commonality would you use to describe the direction toward the spindle centerline?

-X Signup and view all the answers

What is a triangle that contains an angle grater than 90° called?

An oblique triangle. Signup and view all the answers

What is the taper per foot of a taper with D=14, d=2, TL=10?

14.4 Signup and view all the answers

What is the large diameter of a taper with d=2, TL=10, TPF=10.08?

10.40 Signup and view all the answers

The diameter of a circular hole that the machinist has to cut is 35.6 mm. What is the circumference of this hole?

111.8mm Signup and view all the answers

Purchasing an $8700 pump you pay $609 in sales tax. What percent sales tax are you paying?

7% Signup and view all the answers

What is the TPF for a Jarno taper system?

0.600 Signup and view all the answers

If 1kg = 2.2 lbs, a millwright that weighs 225 lbs would weigh how many kg?

They would weigh 102.1 kg. Signup and view all the answers

A journeyperson machinist makes $32.45 per hour. If he/she is given a 4.5% raise, how much per hour would the machinist be making?

He/she would now be making $33.91 per hour Signup and view all the answers

Which of the following best describes a steep machine taper?

It has a 3 1/2 inch taper per foot. Signup and view all the answers

What is the angle most often used to draw isometric drawings?

30 degrees Signup and view all the answers

A circle drawn in an isometric projection would form an ellipse.

True Signup and view all the answers

When referring to machinist blueprints, what do the arrows on the ends of the section lines indicate?

They indicate the direction to view the section. Signup and view all the answers

What style of set screw point would be turned into a drilled hole to maintain alignment between a collar and a shaft?

Half-dog Signup and view all the answers

How much of a taper does a 12 inch taper key have?

1/8 inch Signup and view all the answers

What is the difference in area between a circular tolerance zone and a square tolerance zone?

57% Signup and view all the answers

When referring to surface finishes, what does the term "nominal surface" mean?

The intended surface of the workpiece as specified in the drawing. Signup and view all the answers

What is the best description for a sliding fit?

Accurate location of parts where parts move and turn freely but are not intended to run freely. Signup and view all the answers

What is a FN2 fit used for?

For ordinary steel parts or light shrink fits on thin sections. Signup and view all the answers

Which of the following type of fit is referred to as a RC4?

Running parts on modern machinery with moderate speeds and journal pressures. Signup and view all the answers

The three common views of an orthographic drawing are:

top, front, and right side Signup and view all the answers

Study Notes

Portable Fire Extinguishers

Class A extinguisher is best for paper fires.

Thread Designation

In Unified thread designation, "2" represents the class of fit.

File Coarseness

As file coarseness increases, the distance between teeth becomes narrower.

Machine Screws

Major diameter of machine screws is largest.

Hacksaw

Hacksaw for cutting tool steel should have 14-18 teeth per inch.
Best blade for cutting cast iron is a hacksaw with 14-18 teeth per inch.
Kerf of a hacksaw is the width of the cut.

Caliper

A 6-inch caliper means the maximum distance it can measure is 6 inches.

Grinder

Open-coated abrasive is used for cleaning workpieces of scale and dirt.
Wheel used for cleaning workpieces is a wire brush wheel.

Surface Speed Formula

As rpm increases, CS (cutter speed) also increases.

CNC Lathe

Tap drill size for M10 1.25 thread is calculated using the tap drill size formula.
Measurement used for CNC lathe tapping operation is pitch diameter.
Safety factor used for public elevator cables is usually 10.

CNC Program

G code G20 specifies inches as the unit of measurement.
M code M05 causes the spindle to stop.
M code M00 causes the program to stop.

Cutting Fluid

Important characteristic of a good quality cutting fluid is its ability to cool and lubricate.

Drill Press

Sensitive drill press is a drill press that can drill accurate, precise holes.

Lathe

Primary axis on a lathe is the z-axis.
Backlash is countered by using a split nut or a backlash eliminator.
Back rake angles are ground on the tool bit.

CNC Turning Centres

Single spindle-single turret arrangement is a common setup for CNC turning centres.
Band file consists of a series of flat, rectangular files.
Axis is a line of motion or direction.

EIA Coding

Maximum number of rows where program characters are found is 16.

Oil Mist Lubrication

Advantage of using an oil mist lubrication system is its ability to reduce lubricant consumption.

Spindle Speed Control

Spindle speed control on a CNC machine is usually controlled by a variable frequency drive.

Machine Stops

Feed reverse lever is found on the lathe.
Lathe stops are used to position the workpiece accurately.
Revolving centre is used to support long, slender workpieces.

CNC Terminology

CNC refers to Computer Numerical Control.
"Parting-off" refers to the process of cutting a workpiece from a larger piece of stock.

Drill Point Angle

Recommended drill point angle for hard materials is 130-135 degrees.
Recommended drill point angle for general purpose use is 118-120 degrees.

Lubrication System

Hydraulic lubrication system relies on a pump to force oil under pressure into a bearing.
Open lubrication system allows lubricant to escape into the environment after it has been applied.

CNC Machines

Quadrant 3 of an X and Z axis is the negative X and positive Z axis region.
When programming a CNC, "T" stands for tool and "S" stands for spindle speed.
NC machines are Numerical Control machines.

Grinding Wheels

"Grit" refers to the size of the abrasive particles in a grinding wheel.

Trigonometry

Angle denoted with polar coordinates when measured counter-clockwise is denoted by a positive sign.
Triangle with an angle greater than 90 degrees is called an obtuse triangle.

Math

TPF (taper per foot) of a taper is calculated using the formula TPF = (D-d)/TL.
Circumference of a circle is calculated using the formula C = πd.
Sales tax is calculated as a percentage of the purchase price.
If 1kg = 2.2 lbs, a millwright weighs 225 lbs = 102.27 kg.
A journeyperson machinist makes $32.45 per hour and receives a 4.5% raise.

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Part 1