Automotive tech Engine machining midterm 1
Calculate the OD of number sized screws as follows
(N x .013) + .060in
A crankshaft bearing with .002in clearance has an oil film ________ inches thick
.001
The lack of rigidity in vernier calipers limits accuracy to approximately __________in.
.002
Select the nearest 1/1000in feeler gauge for a .30mm valve clearance adjustment.
.012in
One millimeter equals
.03937in
When turning or boring, a .025in depth of cut changes the diameter __________in
.050
The outside diameter of a 10-32 thread is __________in.
.190in
The pitch of a 10-24 thread is
1 divided by 24
The pitch of a 10 x 1.25 metric thread is
1.25mm
For drilling a 3/8 inch hole in steel, what RPM is correct?
1060
One inch equals __________ cm.
2.54
The crankpin in an engine with a 4-inch stroke length is offset from the center of rotation
2in
A fastener measures .370in. The nearest nominal size is nearest to
3/8in
Prior to reaming, holes are bored or drilled __________ undersize
5%
Machinist A says that an electrical discharge "tap disintegrator" removes broken tools without damage to the surrounding metal. Machinist B says that this process is limited to broken tools jammed in through holes. Who is right?
A only
Machinist A says that for pipe fittings, tap to five turns of the fitting. Machinist B says tap these threads to five turns of the tap. Who is right?
A only
Machinist A says that rake angles direct chips off of the work. Machinist B says that rake angles are smallest for boring tools. Who is right?
A only
Machinist A says that some anti-seize compounds decrease friction and thereby increase the clamping force at specified torque. Machinist B says that even with these compounds, tighten fasteners to specifications. Who is right?
A only
Machinist A says that the resolution limit of a dial indicator is printed on the face of the indicator. Machinist B says that the resolution limit is .001in. Who is right?
A only
Machinist A says that tightening fasteners by degrees of rotation gives more precise clamping force than tightening with a torque wrench. Machinist B says that this method of tightening increases clamping force. Who is right?
A only
Machinist A says that using a dial bore gauge with a setting fixture to check cylinders is "comparative" measuring. Machinist B says that using a dial bore gauge in this way is "transfer" measuring. Who is right?
A only
Technician A says change oil because of contamination and additive depletion. Technician B says change the oil because it wears out. Who is right?
A only
Technician A says measure deck height from the crankshaft centerline to the block deck. Technician B says measure from the block deck to the piston at TDC. Who is right?
A only
Technician A says that when the engine is cold, coolant bypasses the thermostat and recirculates within the engine. Technician B says that when the engine is cold, coolant recirculates within the pump. Who is right?
A only
The cutting action of grinding wheels is provided by
Aluminum oxide or silicon carbide
Fan clutches engage by
Ambient heat
Machinist A says remove broken taps by drilling. Machinist B says see if it possible to drive small taps through holes or burn out larger taps with a torch. Who is right?
B only
Machinist A says that a smaller nose radius on a single pointed tool improves surface finishes. Machinist B says that reduced feed rates improves surface finishes. Who is right?
B only
Machinist A says that cutting tools cannot be harder than the material machined. Machinist B says that there must be relative motion between the work and cutting tools for chips to form. Who is right?
B only
Machinist A says that damaged spark plug threads require repair by means other than Helicoils. Machinist B says that Helicoil repairs require care to keep threads square with spark plug seats. Who is right?
B only
Machinist A says that each Helicoil tap has its own special pitch. Machinist B says that the pitch is the same as the thread being repaired. Who is right?
B only
Machinist A says that if a one-inch mike reads zero when the spindle and anvil are in contact, the mike is unworn. Machinist B says that the mike is in adjustment. Who is right?
B only
Machinist A says that precision assemblies are most economically manufactured by reducing tolerances on individual parts. Machinist B says that such assemblies are more economical if selectively fitted. Who is right?
B only
Machinist A says that should the pilot hole for an easy out be drilled off center or out of alignment, correct the center-line by re-drilling on center. Machinist B says re-drill through a drill bushing or bore with end mill. Who is right?
B only
Machinist A says that the cutting action of drills is most efficient at the chisel edge. Machinist B says that the chisel edge widens as the drill becomes shorter. Who is right?
B only
Machinist A says that to obtain full strength, fasteners require 1.0 diameter of engagement. Machinist B says that 1.5 diameters are required. Who is right?
B only
Machinist A says that tolerance limits specify high and low limits of clearance. Machinist B says that they specify high and low limits of size. Who is right?
B only
Technician A says calculate the displacement of a cylinder by multiplying Pi times cylinder diameter times stroke length and then dividing by 2. Technician B says multiply Pi times the radius squared times the stroke length. Who is right?
B only
Technician A says measure deck clearance from the crankshaft centerline to the block deck. Technician B says measure from the block deck to the piston at TDC. Who is right?
B only
Technician A says that a four-cylinder engine fires every 360 degrees of rotation. Technician B says that all cylinders fire in 720 degrees of rotation. Who is right?
B only
Technician A says that the check valve in a hydraulic lifter opens when the valve opens. Technician B says that check valves open when valves are closed. Who is right?
B only
Technician A says that the intake valve opens after TDC. Technician B says that the intake valve closes after BDC. Who is right?
B only
Tolerance limits are used in the automotive industry for
Bearing bore and crank journal diameters
Machinist A says square milling and drilling spindles with tables or they bore at angles. Machinist B says square milling spindles or they mill surfaces out of square. Who is right?
Both A and B
Machinist A says that Helicoil repairs require special oversize diameter taps. Machinist B says that Helicoils require special installing tools. Who is right?
Both A and B
Machinist A says that USS and SAE threads are automotive equivalents to the Unified coarse and fine thread series. Machinist B says that there are no coarse or fine series designations for metric fasteners under the ISO system. Who is right?
Both A and B
Machinist A says that all end-milling cutters cut from the sides. Machinist B says that only two-lip end mills bore from the end. Who is right?
Both A and B
Machinist A says that center drills hold location better because of their short length. Machinist B says that center drills form a 60-degree included angle for setting up shafts between centers. Who is right?
Both A and B
Machinist A says that drills and reamers are ground to cut from the ends and not the sides. Machinist B says that these tools follow the alignment and positioning of existing or predrilled holes. Who is right?
Both A and B
Machinist A says that fasteners stretch when tightened to specifications. Machinist B says that so long as specifications are not exceeded, stretch remains within elastic limits. Who is right?
Both A and B
Machinist A says that grinding coolants flush away grit and cool both the wheel and the work. Machinist B says that cutting oils lubricate the cutting action and prevent chip welding on cutting edges. Who is right?
Both A and B
Machinist A says that if the headstock and tailstock are misaligned in a lathe, it cuts on a taper. Machinist B says that because the crank is clamped at both ends in a crank grinder, it grinds out-of-round if centers are misaligned. Who is right?
Both A and B
Machinist A says that if the temperature of a one-inch diameter piston pin increases 100 degrees F, the pin grows .0006in. Machinist B says that the pin bore grows as much as .0012in. Who is right?
Both A and B
Machinist A says that in climb milling, the cutter rotates in the same direction as the work feeds. Machinist B says that in conventional milling, the cutter rotates opposite the direction of the work feed. Who is right?
Both A and B
Machinist A says that in climb milling, the cutter tends to pull the work into the cut. Machinist B says that in conventional milling, cutting from the sides of spiral fluted cutters can unscrew them from collets. Who is right?
Both A and B
Machinist A says that oil plugs, pressure fittings, and other pipe threads are tapered 3/4in per foot. Machinist B says that pipe thread sizes are equivalent to the nominal inside diameters of pipes. Who is right?
Both A and B
Machinist A says that one cc of water weighs one gram. Machinist B says that one cc equals one milliliter. Who is right?
Both A and B
Machinist A says that some anaerobic compounds prevent loosening of threads. Machinist B says that some of these compounds seal threads. Who is right?
Both A and B
Machinist A says that the cross-sectional area of coarse internal threads is greater than that of fine threads. Machinist B says that the cross-sectional area of a fine threaded capscrew is greater than a coarse threaded one. Who is right?
Both A and B
Machinist A says that to reduce tool chatter, decrease speeds. Machinist B says that to reduce chatter, increase feeds. Who is right?
Both A and B
Machinist A says that transfer measurements are made with micrometers and telescoping gauges. Machinist B says that transfer measurements are made with inside and outside micrometers. Who is right?
Both A and B
Machinist A says that transfer measuring is most dependent on skill. Machinist B says that comparative methods are more reliable. Who is right?
Both A and B
Machinist A says that vernier calipers measure both inside and outside diameters. Machinist B says that measure depth. Who is right?
Both A and B
Machinist A says that without sufficient clearance on single point tools, tools overheat. Machinist B says that this limits feed rates. Who is right?
Both A and B
Technician A says that an advantage to overhead cam valve trains is the reduced inertia of moving valve train parts. Technician B says that an advantage to pushrod operated overhead valve engine designs is the compact size. Who is right?
Both A and B
Technician A says that both valves are open at TDC on the exhaust stroke. Technician B says that both valves are closed at TDC compression stroke. Who is right?
Both A and B
Technician A says that compression in a diesel heats air in the chamber to approximately 1000 degrees F. Technician B says that diesel fuel ignites at approximately 600 degrees F. Who is right?
Both A and B
Technician A says that one-third of the heat of combustion goes out the exhaust. Technician B says that one-third goes into the cooling system. Who is right?
Both A and B
Technician A says that pressurizing a coolant mixture of 50 percent ethylene glycol to 15 PSI raises the boiling point to 265 degrees F. Technician B says without pressure, this mixture raises the boiling point to 227 degrees F. Who is right?
Both A and B
In a full-flow filtering system, a plugged oil filter causes oil to
By pass the filter and lubricate the engine
A ratchet stop or friction thimble on a micrometer is used to
Calibrate without regarding to individual feel
Cam lift is equal to the
Maximum mesurement of the cam lobe minus the diameter of the base circle
Machinist A says that a machine reamer forms chips along cutting edges tapered 1/16in per foot. Machinist B says that hand reamers form chips along cutting edges on the 45-degree angle on the end. Who is right?
Neither A or B
Machinist A says that as the percentage of cobalt increases in carbide tools so does resistance to heat. Machinist B says that as the percentage of carbide increases in carbide tools so does resistance to shock. Who is right?
Neither A or B
Machinist A says that evidence of soft grinding action is a burned surface on the work. Machinist B says that evidence of hard grinding action is a scored finish. Who is right?
Neither A or B
Machinist A says that feed rates for milling cutters are in inches per revolution. Machinist B says that feed rates for boring or turning are in inches per minute. Who is right?
Neither A or B
Machinist A says that for turning, set tools below center. Machinist B says that for boring, set tools on center. Who is right?
Neither A or B
Machinist A says that increasing the lead angle on a single pointed tool increases chip thickness and reduces tool life. Machinist B says that increasing the lead angle reduces deflection between the tool and the work. Who is right?
Neither A or B
Machinist A says that the cross-sectional area of the minor diameter determines the strength of internal threads. Machinist B says that the cross-sectional area of the thread determines the strength of an external thread. Who is right
Neither A or B
Machinist A says that ultrasonic testers measure surface finishes. Machinist B says that profilometers measure casting thickness. Who is right?
Neither A or B
Technician A says introducing exhaust gas into the intake stream reduces unburned hydrocarbons. Technician B says that precise control of fuel mixtures reduces nitrogen oxides. Who is right?
Neither A or B
Technician A says that duration is the time both valves are open. Technician B says that it is the time that both valves are closed. Who is right?
Neither A or B
Technician A says that the exhaust valve closes after BDC. Technician B says the valve closes before BDC. Who is right?
Neither A or B
The most current duty gasoline engine oil listed below is
SM
The reading of a dial indicator from high to low is called the
TIR or Total indicator reading
With specifications in inches, tapped head bolt holes in engine block and cylinder head castings use__________ threads.
UNC OR USS
Machinist A says that relative to HSS, carbide tools run one-third as fast. Machinist B says that HSS better resists shock. Who is right?
b only
Hole alignments or positions are changed using
boring tools or end mills
Machinist A says that high carbon steel has sufficient hardness for cutting tools but cutting speeds are limited. Machinist B says that HSS tools retain hardness better at high temperatures. Who is right?
both A and B
Machinist A says that thread pitch is the distance between threads. Machinist B says that it equals the distance a fastener travels per revolution. Who is right
both A and B
Overlap is the period when
both valves are open
The most reliable method of measuring clearances is
comparative
The formula for compression ratio is
displacement plus clearance volume divided by clearance volume
To convert specifications given in millimeters to inches, the specification must be
divided by 25.4
Valve lift in pushrod engines typically
exceeds cam lift
Drilling operations such as reaming, counterboring, and counter-sinking are done at __________ drilling speed.
half
Oil baffles in the oil pan
keep oil in the sump on braking, acceleration, or cornering
In some rods, there is an oil hole through the rod housing and rod bearing. This oil hole
lubricates the cylinders
Machinist A says that aluminum expands .000006in per inch per degree F. Machinist B says that iron or steel expands .000012in per inch per degree F. Who is right?
neither A or B
Maximum engine oil pressure is limited by the
oil pump pressure regulator valve
Install Helicoils __________ the surface
one full turn below
A dial bore gauge reading of cylinder diameter, if not zero, is
over or under the setting of the dial bore gauge
A piston is specified to fit a 4.030 inch bore with minimum clearance or as much as .001in more. The tolerance on piston diameter is
plus .000, minus .001in
An example of unilateral tolerance is
plus .001in, minus .000in
An example of bilateral tolerance is
plus or minus .001in
As diameter increases, __________ RPM to maintain correct cutting speeds
reduce
Precision assemblies are most economically manufactured by
selectively fitting parts
The spindle axis of a surfacing machine is
tilted in direction of travel
