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Intro to Machining 1210
Exam 2
167
Engineering
Undergraduate 2
04/14/2012
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Term
In which kind of chuck is square or rectangular work set up for center drilling and facing?
 Definition
Independent
Term
The depth of shoulders and steps machined in workpieces held in a chuck are measured with:
 Definition
A hook rule or a depth micrometer
Term
A workpiece is center drilled in the lathe for the purpose of:
 Definition
Spotting a hole for drilling or for turning between centers
Term
Drilling in too far with a center drill:
 Definition
Makes a sharp outer edge which is a poor bearing surface
Term
Center drills break as a result of:
 Definition
Too heavy feed and too low speed
Term
The rough cutting speed for an alloy steel is45 sfm, and the workpiece diameter is 5 inches. What is the correct RPM?
 Definition
RPM = CS X 4/D
Term
When taking a facing cut on a workpiece held in a chuck , the point of the tool should be:
 Definition
On center
Term
A certain workpiece in a lathe chuck must be adjusted so that it runs on center. A suitable tool for this would be a:
 Definition
Dial indicator
Term
An advantage of turning between centers is that:
 Definition
A shaft can be removed or turned end for end without loss of concentricity
Term
Driving force is transmitted to the workpiece when turning between centers by means of a:
 Definition
Drive plate and a lathe dog
Term
Three different centers used in the tailstock are:
 Definition
Pipe, ball bearing and dead centers
Term
If the cutting speed for aluminum is 200 and the workpiece diameter is 2.5 inches, what is the RPM setting for the lathe?
 Definition
RPM = CS X 4/D
Term
The dead center needs to be frequently adjusted between cuts because the:
 Definition
Heat of machining expands the work and tightens it
Term
Bores of machine parts such as gears and pulleys are not made by drilling a lathe without further machining, because drills:
 Definition
Tend to produce oversize holes that run eccentric to the work axis
Term
Large internal threads should be made with:
 Definition
An internal threading tool held in a boring bar and tap and tap wrench by hand
Term
Ordinary knurls make a pattern on the workpiece by:
 Definition
Displacing the material
Term
Some ways to prevent chatter when cutting off material with a parting tool are to use:
 Definition
A light hand feed that makes a chip, low speed, cutting oil, and a rigid setup
Term
The main advantage of boring over reaming in the lathe is that:
 Definition
Boring corrects any eccentricity and runout in the bore and reaming does not
Term
The sharp V thread:
 Definition
Is seldom used today
Term
American National and Unified thread system:
 Definition
Both have the 60-degree included angle but the depth of thread is different
Term
A ¾ inch diameter, 10 TPI, course thread, Unified nut with a Class 2 tolerance would be properly written:
 Definition
3/4-10 UNC – 2B
Term
The percent of thread depth:
 Definition
Refers to the actual minor diameter of the internal thread
Term
M15 x 1.25 refers to
 Definition
ISO Metric designation for a 15mm diameter, 1.25 mm pitch thread
Term
What would the flat on the end of a threading tool for a 10 thread per inch Unified thread be in inches if the formula is P x .125 inch?
 Definition
P = 1/n
Term
One reason for having thread tolerances an classes of fits is:
 Definition
To insure interchangeability of threaded parts
Term
The pitch of the thread is the:
 Definition
Distance between a point on a screw thread to a corresponding point on the next thread
Term
Threads are cut or chased on a lathe with a single point tool by:
 Definition
Making a series of cuts in the same groove
Term
The tool is aligned with a work:
 Definition
With a center gage
Term
When using low cutting speeds and negative rake tools to cut soft metals, the result is often:
 Definition
A built-up edge
Term
In what way does a cutting tool remove metal?
 Definition
By causing it to slide ahead of the tool on a shear plane
Term
Which chip formation would be best for lathe machining?
 Definition
9-shaped
Term
Relative difficulty of machining with regard to tool life, surface finish and power consumption is called:
 Definition
machinability
Term
If a machined part has an irregular, torn surface with many microcracks due to poor practice, what can happen to the service life of the part?
 Definition
The part could fail early due to metal fatigue
Term
When a soft metal produces thick, segmented chips while being turned on a lathe and no cutting fluid is used, what kind of surface finish is expected?
 Definition
A torn, disrupted, rough surface
Term
Positive tool rakes work best:
 Definition
can produce good surface finishes and when cutting at low speeds
Term
Using RPM=CSx4/D , how fast should a 1/2 inch drill turn when drilling mild steel in a drill press if CS is 90?
 Definition
720
Term
Suppose that the lathe or drill press could not be set at the exact calculated speed; what should you do?
 Definition
Set it to the next lower speed
Term
If a grinding wheel is 6 inch diameter and turning at 3500 RPM, what is cutting speed?
 Definition
5250
Term
Roughing feeds in IPR on a small(10 inch swing) lathe should not exceed:
 Definition
.015
Term
The feedrate on a surface grinder for roughing should be about:
 Definition
1/3 the width of the wheel face
Term
If IPM = feed per tooth x number of teeth on a cutter x RPM, what should be the table feed in inches per minute for a 10 tooth cutter, turning at 50 RPM with a feed per tooth of .006 inch?
 Definition
3
Term
Table feeds in IPM are found on what type of machine?
 Definition
Milling machines
Term
How are feeds determined on a drill press?
 Definition
IPR
Term
A 4 inch diameter shaft of alloy steel with a cutting speed of 50 is turned in a lathe using a high-speed tool. At what RPM should the machine be set?
 Definition
50
Term
If the 1/2 inch drill was fastened in the tailstock of a lathe instead of a drill press, how fast should the lathe spindle turn? RPM=csX4/d
 Definition
720
Term
What are the basic functions of cutting fluids?
 Definition
Cooling and lubrication
Term
When a cutting fluid becomes rancid and odorous, what should be done?
 Definition
The old fluid should be replaced and the tank cleared
Term
Why do some synthetic cutting fluids irritate the skin when in prolonged contact?
 Definition
It tends to remove the natural skin oils
Term
Sulfo-chlorinated cuttign oils are better than water-based coolants for:
 Definition
High pressure cutting, such as tapping
Term
What is the greatest disadvantage of spray-mist systems?
 Definition
They are safety hazards from an operators standpoint of inhaling the mist
Term
A single round nozzle supplying cutting fluid to a grinding wheel is rather inefficient because:
 Definition
The spinning grinding wheel tends to blow it away
Term
If a machine such as a small drill press has no coolant pump, how could you best apply cutting fluid to the workpiece?
 Definition
Use a pump oil can
Term
When an operator mixes cutting oils with the water soluble coolant on a machine, what is often the result?
 Definition
A scum forms on the top of the coolant in the tank and becomes rancid
Term
Three major types of cutting fluids(liquid) are:
 Definition
Emulsions, synthetic, and cutting oils
Term
What effect does increasing the cobalt content have on carbides?
 Definition
Tools become tougher
Term
Increasing the fpm by 50 percent over cutting speeds recommended for carbides will:
 Definition
Decrease tool life by over 80 percent
Term
Ceramic tools are made of:
 Definition
Aluminum oxide
Term
Diamond and polycrystalline diamond tools are used to:
 Definition
Machine hard, abrasive materials at high speed
Term
Brazed carbide tools are ground on:
 Definition
Silicon carbide wheels
Term
Ceramic tools should be used:
 Definition
Where excessive wear is evident on carbides
Term
Increasing the nose radius:
 Definition
Make the tool stronger and produces a better surface finish
Term
Which insert shape is strongest and offers the greatest number of possible cutting edges?
 Definition
Round
Term
Normal wear is seen on a carbide tool as:
 Definition
Edge or flank wear
Term
Excessive tool overhang:
 Definition
Will result in chatter
Term
A standard left hand toolholder is best used for turning:
 Definition
close to the headstock
Term
Tools are secured in a tailstock spindle:
 Definition
By their Morse taper shank
Term
Straight shank tools are held in a tailstock with:
 Definition
A drill chuck
Term
Tool height adjustments on a quick-change toolholder are made:
 Definition
with a micrometer collar
Term
Toolholders are used to:
 Definition
securely clamp the tool
Term
High speed steel tools are:
 Definition
Easily shaped into desire forms of tools
Term
Form tools produce a specially shaped machined surface by:
 Definition
Plunging into the workpiece to produce the form of the tool
Term
Chips can be made manageable and safe to the operator by using:
 Definition
Feeds and depths of cut that contribute to chip breaking and by using chip breakers on tools
Term
A high speed lathe tool would have to be above 1300 F(704 C) to be overheated. A temperature of 2000 F(1093 C) could be produced on the cutting edge when grinding by:
 Definition
Using a glazed wheel or by forcing the tool into the wheel
Term
The purpose of side and end relief angles is:
 Definition
The side relief allows for feed into the work and the end relief provides clearance for the tool so it will not rub
Term
The most important aspect of a lathe tool is:
 Definition
The tool geometry, including end and side relief and rake angles
Term
Chucks and face plates are mounted on the spindle by means of:
 Definition
Any one of several types of spindle noses
Term
The independent chuck has
 Definition
Four jaws, each of which can move without affecting the position of the others
Term
A drive center or face driver makes possible the:
 Definition
Driving of work between centers so a cut can be take the full length
Term
Steel spring collets are used:
 Definition
For turning hexagonal, square and round workpieces
Term
The universal chuck has:
 Definition
2, 3, or 6 jaws that all move in or out an equal distance
Term
On lathes where speed changes are made by shifting belts on step cone pulleys, the shift to the low range is made by:
 Definition
Disengaging the bull gear lock pin and moving the back gear lever with the spindle stopped
Term
The lead screw is reversed by shifting the:
 Definition
Feed reverse lever
Term
The sliding gear shifter levers on the quick-change gear box are used for:
 Definition
Selecting feeds or threads per inch
Term
The half-nut lever is used for:
 Definition
Threading
Term
A lathe that is calibrated for single depth:
 Definition
Will take twice the amount turned on the dial from the diameter of the workpiece
Term
Micrometer collars on cross feed and compound feed handles are graduated in:
 Definition
English and English-metric units
Term
The carriage handwheel:
 Definition
Is used for a quick approach and return and for delicate operations not requiring power feed
Term
The feed change lever:
 Definition
Diverts the feed to either the cross slide or the carriage
Term
Speed changes are made on geared head lathes with:
 Definition
Several shifting levers on the headstock
Term
Speed changes are made on geared head lathes with:
 Definition
Several shifting levers on the headstock
Term
When threading, the carriage is moved along the ways by:
 Definition
The lead screw thread
Term
The thread is picked up when a threading tool is removed for grinding by:
 Definition
Replacing the tool in the holder, engaging the half-nuts, and repositioning the tool with the compound and cross feed
Term
Left hand threads are cut by:
 Definition
Using a standard tool, reversing the lead screw, and moving the tool from left to right
Term
The number of threads per inch can be check with a:
 Definition
screw pitch gage
Term
Threading tools are checked for accuracy on the 60-degree angle by using a:
 Definition
Center gage
Term
Tap drill charts are usually based on what percent of threads?
 Definition
75
Term
Large internal threads are often made on the lathe with single point tools because:
 Definition
Various thread forms can be made and they are concentric to the axis work
Term
If d=D-(P*.541*2) is the formula for finding the minor diameter of a unified internal thread, the diameter bore you make for a 1.5 - 6 UNC nut should be how many inches in diameter? n=6
 Definition
P = 1/n
Term
Deflection of the boring bar causes:
 Definition
An undersize, often bell mouth thread
Term
Tap drilled holes may be made more precise by:
 Definition
Reaming, Boring, Drilling with a slightly smaller drill
Term
The percent of thread of the internal thread is effected by:
 Definition
Varying the bore diameter
Term
In what ways are tapers expressed?
 Definition
In degrees and minutes or by taper per inch or taper per foot
Term
The end or edge of a tool may be setup with a protractor to cut a taper. What kinds of taper may be made by this method?
 Definition
Very short at any angle
Term
How can tapers be turned in a lathe?
 Definition
With the compound, taper attachment, offset tailstock and tool methods
Term
A steady rest should be used to:
 Definition
Support long shafts
Term
What is the correct procedure for using the steady rest when the workpiece is rough?
 Definition
Turn a smooth bearing spot
Term
A long, slender shaft must be turned and threaded with an acme thread. It is too springy to machine without support. What can be used to back up the tool?
 Definition
Follower rest
Term
When a shaft has centers, the steady rest is set up?
 Definition
By adjusting the lower jaws finger tight to the shaft while the dead center is in the shaft center, then adjust the top jaw
Term
Translating type screw are used:
 Definition
For imparting motion to a mechanical part
Term
How many degrees is the included angle of a General Purpose Acme threads?
 Definition
29(14.5*2)
Term
General Purpose Acme threads:
 Definition
Bear at the flanks
Term
How many degrees is the included angle of the modified square thread?
 Definition
10
Term
Buttress threads are used:
 Definition
To resist great forces that are exerted in one direction only
Term
Which is the most commonly used and easiest to machine of the translating type threads?
 Definition
Acme
Term
Stub Acme threads are used:
 Definition
Where a shallow depth with coarse pitch is required
Term
In what position is the compound normally set for cutting right hand external Acme threads?
 Definition
14.5 degrees to the right
Term
The Acme tool is aligned to the work with:
 Definition
an Acme tool gage
Term
Very small internal Acme threads are made with:
 Definition
Acme tap sets
Term
The bore size for making a General Purpose Acme internal thread is:
 Definition
The major diameter of the screw minus the pitch
Term
The Acme threading tool forms an included angle of how many degrees?
 Definition
29(14.5*2)
Term
The finest grit size of the ranges listed below is:
 Definition
280 to 500
Term
When a grinding wheel becomes loaded with bits of workpiece material, this shows that:
 Definition
The metal being ground is too soft
Term
When a grinding wheel face becomes shiny and smooth or glazed, this shows that the wheel:
 Definition
Grade is too hard
Term
The bond in most machine shop grinding wheels is:
 Definition
Vitrified
Term
Grade in a grinding wheel specification refers to the:
 Definition
Strength with which the bond holds the grain
Term
For grinding steels, the most widely used abrasive is:
 Definition
Aluminum oxide
Term
Grinding wheel dressing is done to:
 Definition
Sharpen the grinding wheel
Term
The depth of infeed(or downfeed) per pass in trueing should be no more than:
 Definition
.001 inch
Term
An out-of-balance grinding wheel can cause chatter marks on the workpiece and should be balanced to the small weight of a postage stamp. Which of the following statements is true of grinding wheels?
 Definition
Dynamic balancing is preferable
Term
On a grinding wheel rotating clockwise, the correct position for the single point diamond in a dresser is:
 Definition
Pointing in the direction of rotation 15 degrees past the center line
Term
Grinding wheel trueing is:
 Definition
The method of obtaining grinding wheel concentricity of the spindle
Term
For maximum cooling ability in a grinding fluid, you should use:
 Definition
Water soluble chemical type fluids
Term
Air/mist coolant in grinding application:
 Definition
Require adequate ventilation of the work area
Term
For maximum lubricating benefit, the fluid should be:
 Definition
straight oil or sulfo-chlorinated oil
Term
The grinding machine table:
 Definition
Supports the workpiece,usually on a chuck, for grinding
Term
What grinding method helps to keep the grinding surface flat and extend the interval between wheel dressings?
 Definition
Small downfeeding movements with large crossfeeding movements
Term
Which of the following is definitely not an accessory and must always be used?
 Definition
Wheel safety guard
Term
What purpose is served by extending the table overtravel beyond the workpiece dimensions?
 Definition
It gives time for the crossfeeding to take place between passes
Term
The most precise handwheel control on the grinder is the:
 Definition
Down feed
Term
A surface grinder is primarily used for grinding:
 Definition
Flat surfaces
Term
What 2 advantages does the electro-permanent chuck have over an electromagnetic chuck?
 Definition
It generates less heat than the electromagnetic chuck and it retains holding power if electrical power failure occurs
Term
Laminated magnetic accessories must be treated with exceptional care to remain accurate. Why is this?
 Definition
They are exceptionally soft and are easily damaged by burring
Term
What special precaution in holding magnetic workpieces must be considered in placing these pieces on chuck?
 Definition
The workpieces must span as many magnetic poles as possible
Term
What is the most commonly used workholding device on the surface grinder?
 Definition
The permanent magnet chuck
Term
Avoiding metallurgical damage during grinding is often of critical importance for what primary reason?
 Definition
The safety of parts subjected to large and variable loading such as bearings, missiles & aircraft applications
Term
To avoid the use of paper to protect the surface of the chuck, what must be done to prepare a scaly heat treated workpiece before grinding?
 Definition
The heat treatment scale must be removed before chucking
Term
When grind the 'vee' in your vee blocks, what critical caution should you observe?
 Definition
You should not make contact with the side of the grinding wheel
Term
To square the end of a workpiece with a ground side, the surface clamped to the angle plate must be:
 Definition
The ground side
Term
Why is it advisable to remove as little material as possible in the first clean-up grind?
 Definition
It provides you with the most latitude in bringing the workpiece to final dimensions
Term
What precaution should be observed in determining whether or not to use grinding fluid while trueing or dressing a grinding wheel?
 Definition
If full fluid coverage cannot be assured, dress drry
Term
For grinding harder workpieces of the same material, what variation in crossfeeding is usually applied?
 Definition
The crossfeeding rate is decreased
Term
The importance of horizontal spindle surface grinding is increasing for what primary reason?
 Definition
Tolerances of 50 millionths of an inch are getting more common
Term
The objection to a burnished surface is that it:
 Definition
Is damaged and may not be safe in service
Term
Too much grinding heat can cause:
 Definition
discoloration or burning
Term
Can the plain cylindrical grinder produce a tapered(conical) surface?
 Definition
Yes, the table can be swiveled for this purpose
Term
On a cylindrical grinder the workpiece surface moves in relation to the direction of travel of the grinding wheel surface:
 Definition
In the opposite direction
Term
Among cylindrical grinding machines, the greatest variety of work can be done on a:
 Definition
universal grinder
Term
If a part has a taper of 0.010 in/ft, the difference between 2 dial indicator readings 12 inches apart would be ____ inch(Hint: indicator reads on the radius)
 Definition
0.005
Term
For final finishing passes on the cylindrical grinder, the amount to be removed per traverse should be:
 Definition
.0002 inches or less
Term
When traversing stops are being set, how much of the wheel width should be permitted to overtravel the ground part length?
 Definition
At least 1/3 of the wheel width
Term
If a cutter is ground with excessive clearance, what happens when the cutter is used?
 Definition
The cutting edge breaks down quickly for lack of support
Term
Which clearance on the periphery of a cutter is ground first, and why?
 Definition
The primary clearance because the wheel is sharper on the initial cut and therefore cuts cooler
Term
To preserve the desired cutter shape in a form relieved cutter, what surface is sharpened, and what precaution is observed?
 Definition
It must be ground only on the face and radial to the cutter axis
Term
What tool and cutter grinder accessory is necessary for grinding the clearances on both the ends of end milling cutters and the side teeth of stagger tooth cutters?
 Definition
A tilting workhead
Term
Where is the toothrest mounted when grinding the periphery of helical cutters?
 Definition
It is mounted on the wheelhead
Term
Why is it helpful to the cutter grinding machinist to know what material the cutter is to be used for?
 Definition
Differing workpiece materials call for differing cutter clearances
Term
What fundamental machine design capability differentiates a tool and cutter grinder from a universal cylindrical grinder?
 Definition
The ability to raise and lower the wheelhead
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