I85PREP
⌘ K
COREN Craftsman study materials
COREN Craftsman study resources

COREN Craftsman practice questions

One question at a time. Build your COREN Craftsman understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Engineering Craft Practice and Workshop Technology

In a workshop, the safe working practice when using a pedestal grinder is to stand slightly to one side of the wheel during start-up because:

  1. the tool rest must be adjusted while the wheel is spinning
  2. the wheel may burst if it has been damaged or improperly mounted Correct answer.
  3. the wheel runs cooler when approached at an angle
  4. the motor draws less current when the operator is off-axis

Explanation

Bonded abrasive wheels can fracture and eject fragments if cracked or incorrectly mounted, so standing out of the wheel's plane during run-up protects the operator. The guard and tongue guard further limit exposure to fragments. Current draw and wheel temperature are not the reason for this practice.

Question 2Engineering Craft Practice and Workshop Technology

A bench vice fitted with soft jaws is most appropriate when holding:

  1. a workpiece requiring maximum clamping force
  2. a rough casting that must be filed flat
  3. a polished workpiece that must not be marked Correct answer.
  4. a pipe that needs heavy torque applied

Explanation

Soft jaws (often aluminium or copper liners) distribute clamping pressure and protect finished surfaces from the serrations of hardened jaws. They are not intended for the high clamping loads needed on rough castings or pipes. For maximum grip on hard work, plain hardened jaws are used.

Question 3Engineering Craft Practice and Workshop Technology

When marking out a steel plate, layout blue (marking-out fluid) is applied before scribing because it:

  1. lubricates the scriber tip to extend its life
  2. prevents the scriber from slipping off the edge
  3. hardens the surface so the line stays sharp
  4. makes the scribed line visible against the coated surface Correct answer.

Explanation

Layout blue provides a contrasting background so fine scribed lines are clearly visible and can be followed during cutting and machining. It does not harden the metal or significantly lubricate the scriber. Scribing is done with a sharp point that raises a fine burr, which the coating makes easier to see.

Question 4Engineering Craft Practice and Workshop Technology

The main purpose of a centre punch mark before drilling a hole is to:

  1. enlarge the hole slightly so the drill runs cooler
  2. provide a thread lead-in for later tapping
  3. guide the drill point so it starts without wandering Correct answer.
  4. remove the hardened skin left by a previous cut

Explanation

A centre punch produces a small conical indentation that locates the drill point at the marked position and prevents it from skidding across the surface as drilling begins. It does not enlarge the hole or remove work-hardened material. Thread lead-in is formed by chamfering, not by punching.

Question 5Engineering Craft Practice and Workshop Technology

A hacksaw blade with 18 teeth per inch is the better choice than a 32 TPI blade when cutting:

  1. a thick solid mild steel bar Correct answer.
  2. a hardened file tang
  3. sheet metal under 1 mm thick
  4. thin-walled copper tube of 1 mm wall

Explanation

Coarse pitches such as 18 TPI give more chip clearance and cut faster in thick solid sections. Fine pitches are reserved for thin sections where coarse teeth would snag or straddle the work. Hardened material is not cut with a standard hacksaw blade at all.

Question 6Engineering Craft Practice and Workshop Technology

In a simple spur gear train, the velocity ratio is determined by:

  1. the addendum circle diameter of the driving gear
  2. the number of teeth on the driving and driven gears Correct answer.
  3. the module of the gears only
  4. the face width of the driven gear

Explanation

For meshing spur gears the speed ratio equals the inverse ratio of tooth numbers, so the tooth counts of driver and driven gears set the velocity ratio. Module, addendum and face width affect strength and geometry but cancel out of the ratio. This is why interchangeable gears are specified by tooth count.

Question 7Engineering Craft Practice and Workshop Technology

The correct procedure for tightening the wheel nut on a bench grinder is to:

  1. leave the nut finger-tight to allow wheel expansion
  2. tighten only enough to drive the wheel, using the correct flange Correct answer.
  3. apply thread-locking compound to the spindle thread
  4. tighten firmly with a long spanner for maximum grip

Explanation

Over-tightening the wheel nut can crack the abrasive wheel, so it is tightened just enough to drive the wheel through the flanges. Blotters and matching flanges distribute the load. Thread-locking compound is never used because the nut must be removable for wheel changes.

Question 8Engineering Craft Practice and Workshop Technology

When using a hand file, the correct technique for removing material efficiently on a mild steel bar is to:

  1. use the file edge-on to concentrate force
  2. lift the file clear of the work on every return stroke
  3. apply pressure on the forward stroke and release on the return Correct answer.
  4. apply equal heavy pressure on both forward and return strokes

Explanation

Files cut on the forward stroke, so pressure is applied then and eased on the return to avoid dulling the teeth. Dragging the file back under heavy pressure wears the teeth prematurely. Lifting clear on every stroke wastes time and disrupts the cutting rhythm.

Question 9Engineering Craft Practice and Workshop Technology

A workpiece is to be drilled on a pedestal drill. Which practice best prevents the workpiece spinning and injuring the operator?

  1. Holding the workpiece by hand and feeding slowly
  2. Clamping the workpiece or using a drill vice bolted or clamped to the table Correct answer.
  3. Starting the drill at maximum spindle speed
  4. Wearing gloves to improve grip on the workpiece

Explanation

The workpiece must be restrained by clamping or a properly secured vice so that torque from the drill cannot spin it. Hand-holding is a common cause of serious injury when the drill grabs. Gloves near rotating spindles are themselves hazardous.

Question 10Engineering Craft Practice and Workshop Technology

A taper pin is to be fitted through two mating plates. The taper reamer is used because:

  1. it allows the hole to be drilled and tapped in one operation
  2. it produces a hole matching the taper of the pin for a tight, play-free fit Correct answer.
  3. it work-hardens the hole surface for greater wear resistance
  4. it cuts faster than a parallel reamer in thin plate

Explanation

A taper pin relies on a matching tapered hole to seat firmly and resist loosening, so the hole is finished with a taper reamer of the same taper rate as the pin. A parallel reamer would leave line contact only. Reaming does not work-harden for wear resistance or combine with tapping.

Question 11Engineering Craft Practice and Workshop Technology

When turning a taper on a centre lathe using the compound (topslide) swivel method, the angle set on the swivel is:

  1. the full included angle of the taper
  2. half the included angle of the taper Correct answer.
  3. the angle of the taper plus 90 degrees
  4. the helix angle of the workpiece surface

Explanation

The topslide feeds along the side of the taper, so the swivel is set to half the included angle, measured from the lathe axis. Setting the full included angle would produce a taper twice as steep as required. The helix angle relates to screw cutting, not taper turning.

Question 12Engineering Craft Practice and Workshop Technology

A reamer is specified with a cutting diameter slightly larger than the drilled hole. The reason is that a reamer:

  1. removes a small amount of material and tends to cut slightly under nominal size Correct answer.
  2. requires a pre-existing thread to guide it
  3. only works in non-ferrous metals
  4. is designed to enlarge a hole by 10 percent or more

Explanation

Reamers remove only a few thousandths of material and can spring or cut slightly under size, so holes are drilled undersize and the reamer is selected to suit the finished diameter. Reaming is a finishing operation, not a bulk-enlarging one. It is used on ferrous and non-ferrous metals alike.

Question 13Engineering Craft Practice and Workshop Technology

The correct order of operations when producing an internal thread in a blind hole in mild steel is to:

  1. drill the tapping size, countersink the mouth, then tap Correct answer.
  2. tap the hole, then drill, then countersink
  3. countersink, tap, then drill the clearance hole
  4. drill the clearance size, tap, then countersink

Explanation

The tapping-size hole is drilled first, the mouth is chamfered to guide the tap and prevent burring, and then the thread is cut. Tapping before drilling is impossible, and drilling clearance size would leave too large a hole for the thread.

Question 14Engineering Craft Practice and Workshop Technology

In a chain-drive system on workshop machinery, the chain is correctly tensioned so that:

  1. it has a small amount of slack on the slack side to avoid overloading bearings Correct answer.
  2. it is tensioned only when the machine is running at full speed
  3. it hangs loosely enough to skip a tooth under load
  4. it is as tight as possible to eliminate all slack

Explanation

Chains need a small controlled amount of sag on the slack side; over-tensioning loads shafts and bearings and accelerates wear, while excessive slack causes jumping and shock loads. Tension is set with the drive stopped. Correct sag is specified by the manufacturer.

Question 15Engineering Craft Practice and Workshop Technology

A flat surface is being checked with a dial test indicator on a surface plate. The indicator reads zero at the centre and plus 0.04 mm at the edges. The surface is:

  1. convex, with the centre higher than the edges
  2. flat within 0.04 mm across its whole width
  3. twisted diagonally rather than dished
  4. concave, with the edges higher than the centre Correct answer.

Explanation

With the stylus reading zero at the centre and positive at the edges, the edges stand proud of the centre, which describes a concave surface. A convex surface would read the opposite way. Twist would show as opposite signs on diagonally opposite corners rather than a symmetric edge rise.

Question 16Engineering Craft Practice and Workshop Technology

When soft-soldering a copper pipe joint with a lead-free solder, the flux is applied so that:

  1. it hardens the copper locally to resist vibration
  2. it chemically cleans the surfaces and excludes oxide during heating Correct answer.
  3. it raises the melting point of the solder for a stronger joint
  4. it acts as a filler to bridge large gaps in the joint

Explanation

Flux removes oxide and protects the cleaned surfaces from re-oxidising while the joint is heated, allowing the solder to wet and flow by capillary action. It is not a filler and does not raise the melting point. Joint strength depends on a close capillary gap, not on flux volume.

Question 17Engineering Craft Practice and Workshop Technology

A bearing is described as 6205. In standard bearing designation, the '05' indicates:

  1. an outside diameter of 5 mm
  2. a bore diameter of 25 mm Correct answer.
  3. a bore diameter of 5 mm
  4. a series number for light duty

Explanation

For bore codes 04 and above, the bore diameter in millimetres is the code multiplied by five, so 05 corresponds to 25 mm. The preceding digits denote the bearing type and series. The bore is not the raw code value nor the outside diameter.

Question 18Engineering Craft Practice and Workshop Technology

A shaft is to be fitted into a bore with a light press fit. Which combination is most appropriate?

  1. Shaft and bore both at their lower limits
  2. Shaft at the upper limit and bore at the lower limit of their tolerances Correct answer.
  3. Shaft at the lower limit and bore at the upper limit
  4. Shaft and bore both at their upper limits

Explanation

A press fit requires interference, which is achieved when the shaft is at its largest permissible size and the bore at its smallest. The opposite combination gives clearance and a loose fit. Matching both at the same limit gives an unpredictable result rather than guaranteed interference.

Question 19Engineering Craft Practice and Workshop Technology

During gas welding of mild steel, a carburising (reducing) flame is produced when:

  1. oxygen is in excess of the acetylene supply
  2. acetylene is in excess of the oxygen supply Correct answer.
  3. the torch is fitted with a larger nozzle than specified
  4. oxygen and acetylene are supplied in equal proportions

Explanation

An excess of acetylene produces a three-zone carburising flame with a feathery secondary cone, which adds carbon to the weld pool. Excess oxygen gives an oxidising flame, and equal proportions give a neutral flame. Nozzle size changes heat input, not the flame chemistry.

Question 20Engineering Craft Practice and Workshop Technology

A surface is to be protected with a primer before a top coat. The main function of the primer is to:

  1. provide adhesion and corrosion inhibition against the prepared substrate Correct answer.
  2. fill deep pitting in the steel surface
  3. act as a release agent for later machining
  4. give the final colour and gloss to the finished work

Explanation

Primers bond to the prepared surface and contain corrosion-inhibiting pigments that protect the steel beneath the top coat. Colour and gloss come from the top coat, and deep pitting is filled with stopper or filler, not primer alone. A release agent would prevent adhesion.

Question 21Engineering Craft Practice and Workshop Technology

On a centre lathe, a workpiece set in a three-jaw self-centring chuck is found to run out by 0.15 mm when indicated near the chuck but 0.30 mm at the free end. The most likely cause is:

  1. the tool is set below centre height
  2. the spindle speed is too high for the material
  3. the chuck jaws are worn or the workpiece is gripped on a rough surface Correct answer.
  4. the tailstock is set over by exactly 0.15 mm

Explanation

Run-out that increases away from the chuck points to the workpiece being held off-axis by the jaws, often from wear or from gripping an irregular surface. Tailstock set-over produces a taper, not a doubling run-out of this kind. Speed and tool height do not create this run-out pattern.

Question 22Engineering Craft Practice and Workshop Technology

A milling cutter is climb milling a steel block on a machine with a worn leadscrew. The practice is risky because:

  1. climb milling removes too little material per pass
  2. the cutter rotates in the wrong direction for the spindle
  3. climb milling requires a coolant that is not normally available
  4. the cutter tends to drag the table into the work, causing backlash to be taken up violently Correct answer.

Explanation

In climb milling the cutter's rotation tends to pull the table along the feed direction, so any backlash in the leadscrew allows the work to be grabbed, causing chatter or breakage. Conventional milling opposes the feed and is safer on worn machines. Cutter rotation and coolant are not the reason.

Question 23Engineering Craft Practice and Workshop Technology

A component is to be case hardened to give a hard wear-resistant skin while retaining a tough core. Which process achieves this?

  1. Annealing the component after rough machining
  2. Through hardening by quenching the whole section
  3. Normalising to refine the grain structure
  4. Carburising followed by quenching and tempering Correct answer.

Explanation

Carburising raises the carbon content of the surface layer, and subsequent quenching hardens that skin while the low-carbon core remains tough. Through hardening hardens the whole section, losing core toughness. Annealing and normalising are softening or grain-refining treatments, not surface hardening.

Question 24Engineering Craft Practice and Workshop Technology

A precision shaft is to be measured with a micrometer and the reading must be reliable. Which practice gives the most trustworthy result?

  1. Zero the micrometer on the workpiece rather than on a gauge
  2. Measure at one position only and accept the first reading
  3. Use the ratchet or friction thimble to apply consistent measuring force Correct answer.
  4. Tighten the thimble firmly by hand until the anvils grip the shaft

Explanation

The ratchet or friction stop limits and standardises measuring force so readings are repeatable and the instrument is not distorted. Measuring at several positions along and around the shaft reveals taper and ovality. Zeroing is done on a gauge or the anvils closed, not on the workpiece.

Question 25Engineering Craft Practice and Workshop Technology

A welded steel fabrication is found to have cracked adjacent to the weld after cooling. The most likely cause is:

  1. excessive restraint and rapid cooling producing hard, brittle heat-affected zone Correct answer.
  2. the parent metal was cleaned before welding
  3. the weld was made with a slightly larger nozzle than required
  4. the welding current was set to the manufacturer's recommendation

Explanation

Rapid cooling and heavy restraint raise hardness and residual stress in the heat-affected zone, promoting cracking. Preheating, controlled cooling and stress relief reduce the risk. Nozzle size, cleanliness and correct current are good practice and do not cause this defect.

Question 26Engineering Craft Practice and Workshop Technology

When marking out a steel plate with a scriber and steel rule, the layout lines are scribed rather than drawn with a pencil mainly because scribed lines:

  1. are easier to see on bright steel
  2. do not smudge or wear away during handling Correct answer.
  3. allow the rule to be used as a straightedge
  4. are the only lines accepted by a datum

Explanation

A scriber cuts a fine groove into the surface of the metal, so the line survives handling, cutting and filing far better than a pencil mark, which rubs off easily. The groove also gives a sharp, precise edge for aligning a punch or saw. Visibility on bright steel is not the main reason, since scribed lines can be faint.

Question 27Engineering Craft Practice and Workshop Technology

A hacksaw blade is being fitted to a frame for cutting mild steel bar. The blade should be fitted so that:

  1. the blade is tensioned loosely to allow it to follow the cut
  2. the blade is fitted with the teeth facing the operator's body
  3. the teeth point towards the handle and cut on the forward stroke
  4. the teeth point away from the handle and cut on the forward stroke Correct answer.

Explanation

A hacksaw blade is fitted with the teeth pointing away from the handle so that the cutting action occurs on the forward (push) stroke, when the operator can apply controlled pressure. The return stroke then lifts the blade clear of the chips. Correct tensioning, not looseness, keeps the blade straight in the cut.

Question 28Engineering Craft Practice and Workshop Technology

A twist drill is being ground on a bench grinder for drilling mild steel. The point angle normally aimed for is:

  1. 150 degrees
  2. 60 degrees
  3. 118 degrees Correct answer.
  4. 90 degrees

Explanation

The standard twist drill point for general steel work is approximately 118 degrees, which balances cutting efficiency with strength at the cutting lips. A point that is too sharp wears quickly, while a very blunt point needs excessive thrust. Both lips must also be ground equal in length and angle.

Question 29Engineering Craft Practice and Workshop Technology

A flat chisel is being used to shear a rivet head from a steel plate. The chisel should be held so that the cutting edge:

  1. lies flat against the work surface with the bevel down
  2. is driven with the bevel facing upward and the flat face on the work
  3. is angled at about 45 degrees to the work surface
  4. is presented square to the work with a slight clearance angle Correct answer.

Explanation

For shearing a rivet head, the chisel is presented square to the work with a small clearance angle so the edge bites without the flat face rubbing. The bevel is kept on the waste side and the cut is made in a controlled series of blows. This keeps the cut flat and protects the plate beneath.

Question 30Engineering Craft Practice and Workshop Technology

A hole is being tapped in aluminium and the tap squeaks and binds part way in. The most appropriate immediate action is to:

  1. continue turning with more force to clear the obstruction
  2. withdraw the tap and redrill the hole one size larger
  3. strike the tap with a hammer to reseat it in the hole
  4. reverse the tap a half turn, clear the chips and apply more lubricant Correct answer.

Explanation

Binding and squeaking indicate chip packing and poor lubrication. Backing the tap a half turn breaks the chips, and clearing them plus adding suitable lubricant (paraffin is common for aluminium) lets the tap continue without seizing. Forcing a bound tap usually breaks it in the hole.

Question 31Engineering Craft Practice and Workshop Technology

A precision ground flat surface is to be checked for straightness using a dial test indicator mounted on a surface gauge. The most reliable method is to:

  1. sweep the indicator over the whole surface and note the largest reading
  2. place the indicator on the surface and tap the surface plate to settle it
  3. traverse the indicator along straight lines and compare readings at each position Correct answer.
  4. take one reading at the centre and assume the surface is flat

Explanation

Straightness is assessed by traversing the indicator along defined lines and comparing the readings at each point, so that local high and low spots are revealed. A single reading or a general sweep gives no information about variation along the surface. The surface plate provides the flat reference for the gauge.

Question 32Engineering Craft Practice and Workshop Technology

A bench vice is used to hold a finished, polished component for a light filing operation. To avoid marking the work, the correct practice is to:

  1. tighten the vice only finger-tight so the work can move
  2. place the work on top of the jaws and hold it by hand
  3. fit soft jaw covers and grip the work between them Correct answer.
  4. grip the work directly in the serrated jaws and file lightly

Explanation

Soft jaws (often aluminium or copper covers) spread the clamping load and protect a finished surface from the serrated jaws. The work is still held firmly enough for light filing. Direct gripping in serrated jaws or loose holding both risk damage or movement.

Question 33Engineering Craft Practice and Workshop Technology

A centre punch mark is to be made before drilling a hole in a steel plate. The centre punch should be:

  1. used only after the hole has been drilled as a witness mark
  2. held vertically and struck once firmly to form a clear cone Correct answer.
  3. struck repeatedly with light taps until a deep hole appears
  4. held at an angle so the point can be seen clearly

Explanation

The centre punch is held vertically over the intersection of the layout lines and struck once firmly, producing a cone that guides the drill point. A single accurate blow is better than repeated light taps, which tend to wander. The punch mark must be made before drilling, not after.

Question 34Engineering Craft Practice and Workshop Technology

A length of mild steel bar is to be bent to a right angle in a bench vice. To reduce distortion and cracking at the bend, the bend line should be:

  1. heated to a bright red before bending cold
  2. positioned just above the jaw faces and bent slowly Correct answer.
  3. positioned level with the jaw faces and struck sharply
  4. made with a hacksaw cut before bending

Explanation

Placing the bend line just above the jaws gives the material room to form a radius rather than being crushed against the jaw edge, and bending slowly avoids shock loads that crack the outside of the bend. The inside of the bend should also be supported or the bar will flatten.

Question 35Engineering Craft Practice and Workshop Technology

A file is being used on a soft aluminium workpiece and the teeth quickly clog. The most appropriate action is to:

  1. use the file on steel first to sharpen the teeth
  2. clean the file with a file card and rub chalk on the teeth Correct answer.
  3. continue filing dry and ignore the clogging
  4. press harder to force the chips through the teeth

Explanation

Soft aluminium fills the file teeth (pinning), so the file must be cleaned regularly with a file card and the teeth rubbed with chalk to reduce adhesion. Pressing harder only embeds more metal. A coarse-toothed file also helps on soft metals.

Question 36Engineering Craft Practice and Workshop Technology

A hole is to be drilled in a thin sheet of steel on a pedestal drill. To prevent the drill snatching and tearing the sheet, the best practice is to:

  1. hold the sheet by hand and feed the drill slowly
  2. use a large drill at high speed with heavy feed
  3. clamp the sheet to a backing board and use a small pilot drill first Correct answer.
  4. drill from the underside without support

Explanation

Thin sheet tears and snatches because the drill breaks through with little material around it. Clamping the sheet to a backing board supports the exit side, and a pilot hole lets the final drill cut evenly. Hand-holding thin sheet on a drill is dangerous.

Question 37Engineering Craft Practice and Workshop Technology

A surface is being finished by hand scraping to improve bearing contact. The identifying feature of a correctly scraped surface is:

  1. deep parallel grooves running across the surface
  2. a uniform mirror polish over the whole area
  3. a pattern of shallow hollows separated by bearing spots Correct answer.
  4. a single large flat area with no high spots

Explanation

Scraping removes small amounts of metal from the high spots, leaving a pattern of shallow hollows with the bearing spots (the marked high points) proud of them. This gives the oil-retaining, evenly bearing surface required. A mirror polish or deep grooves would not provide correct bearing contact.

Question 38Engineering Craft Practice and Workshop Technology

A shaft is to be assembled into a bearing housing and the fit is specified as a transition fit. This means the assembly will:

  1. always have a clearance between shaft and bore
  2. have either a small clearance or a small interference depending on actual sizes Correct answer.
  3. always be an interference requiring a press
  4. require the shaft to be shrunk with liquid nitrogen

Explanation

A transition fit lies between clearance and interference fits, so the actual sizes may give a small clearance or a small interference. It is used where the parts must locate accurately but may still be assembled without excessive force. Shrink fitting belongs to heavy interference fits.

Question 39Engineering Craft Practice and Workshop Technology

A surface plate is being used as a datum for measurement. Before use, the plate should be:

  1. coated with a thin film of oil to aid sliding
  2. warmed with a hot air gun to drive off moisture
  3. loaded with the heaviest workpiece available to settle it
  4. cleaned and checked for burrs, with the work allowed to reach room temperature Correct answer.

Explanation

A surface plate must be clean and free of burrs so the work sits truly on the datum, and the work should be at the same temperature as the plate to avoid thermal expansion errors. Oil films and heat both introduce measurement error. Loading the plate has no settling effect.

Question 40Engineering Craft Practice and Workshop Technology

A vernier caliper is used to measure the outside diameter of a turned shaft. The reading is taken with the jaws closed on the work and the caliper:

  1. clamped tightly so the jaws mark the shaft
  2. held with only the jaw tips touching the shaft
  3. tilted so the jaws contact the shaft on a diagonal
  4. held square to the shaft axis with light, even jaw pressure Correct answer.

Explanation

The caliper must be square to the axis and closed with light, even pressure so the jaws contact the full diameter without deflecting the instrument. Tilting or using only the jaw tips gives a false reading across a chord rather than the diameter. Tight clamping distorts the jaws and the work.

Question 41Engineering Craft Practice and Workshop Technology

A workpiece is being set up on a milling machine and a dial test indicator is used to align a vice. The indicator should be:

  1. mounted on the machine spindle or a magnetic base and swept along the vice jaw Correct answer.
  2. placed on the table and read without touching the vice
  3. held by hand against the jaw while the table is moved
  4. clamped to the workpiece and read while the cutter runs

Explanation

The indicator is mounted rigidly on the spindle or a magnetic base and swept along the vice jaw while the table is adjusted, so the jaw is brought parallel to the machine axis. Hand-holding or clamping to the work gives no stable reference. The spindle must be stationary for the sweep.

Question 42Engineering Craft Practice and Workshop Technology

A workpiece held in a machine vice on a shaping machine is being cut with a tool that lifts on the return stroke. The clapper box allows this so that:

  1. the ram can run at a higher speed
  2. the tool can be swivelled for angular work
  3. the cutting edge is lifted clear and does not drag or wear on the return Correct answer.
  4. the tool cuts on both strokes for higher output

Explanation

The clapper box hinges so the tool lifts slightly on the return stroke, preventing the cutting edge from dragging back across the work and wearing or chipping. The tool then seats firmly for the cutting stroke. It does not make the tool cut on both strokes.

Question 43Engineering Craft Practice and Workshop Technology

A grinding wheel is being mounted on a bench grinder and a ring test has been carried out. The purpose of the ring test is to check that the wheel:

  1. is balanced on the spindle
  2. is free from cracks or internal damage Correct answer.
  3. is the correct diameter for the guard
  4. has the correct grade for the work

Explanation

In the ring test the wheel is tapped lightly and should give a clear ring; a dull thud suggests a crack or internal damage and the wheel must be rejected. It is a safety check for soundness, not for grade, size or balance. A damaged wheel can burst at speed.

Question 44Engineering Craft Practice and Workshop Technology

A steel component is to be protected from corrosion while buried in soil. Which coating system is most suitable for this service?

  1. A coat of light machine oil wiped on before burial
  2. A temporary layout dye coating
  3. A hot-applied bituminous or epoxy coating applied to the specified thickness Correct answer.
  4. A single thin coat of cellulose lacquer

Explanation

Buried steel needs a thick, continuous barrier coating such as hot bitumen or a suitable epoxy system applied to the specified dry film thickness. Thin decorative or temporary coatings break down quickly in soil and offer little protection. Surface preparation before coating is equally important.

Question 45Engineering Craft Practice and Workshop Technology

A bearing is to be fitted to a shaft by heating the bearing in an oil bath. The purpose of heating is to:

  1. harden the bearing material before assembly
  2. expand the bore so the bearing slides onto the shaft without force Correct answer.
  3. soften the bearing race so it can be pressed on
  4. melt the lubricant so the bearing runs cooler

Explanation

Heating expands the bearing bore so it can be slipped onto the shaft; as it cools it contracts to give the required interference fit. The bearing must not be overheated, as this damages the temper and the lubricant. The shaft is not softened or hardened by this process.

Question 46Engineering Craft Practice and Workshop Technology

A component made from high-carbon steel is to be hardened and then tempered. The purpose of tempering is to:

  1. increase the hardness beyond the as-quenched value
  2. restore the soft annealed condition completely
  3. relieve quenching stresses and reduce brittleness while retaining toughness Correct answer.
  4. prevent the formation of martensite during quenching

Explanation

As-quenched high-carbon steel is very hard but brittle and highly stressed. Tempering, a controlled reheat below the critical range, relieves those stresses and trades some hardness for toughness. It does not soften the steel back to the annealed condition.

Question 47Engineering Craft Practice and Workshop Technology

A brazed joint is to be made between two copper tubes. Compared with soft soldering, brazing is characterised by:

  1. the use of no flux at all
  2. a joint that relies only on mechanical clamping
  3. a higher working temperature and a filler that melts above the parent metal's soldering range Correct answer.
  4. a lower working temperature and a lead-based filler

Explanation

Brazing uses filler metals that melt at higher temperatures than soft solders (typically above about 450 degrees Celsius) and gives stronger joints. A suitable flux is still needed to prevent oxidation. The joint is metallurgical, not merely clamped.

Question 48Engineering Craft Practice and Workshop Technology

A welded joint in mild steel shows porosity along the weld bead. Which cause is most likely?

  1. Correct electrode storage and clean plate
  2. Excessive current with a short arc
  3. Too slow a travel speed with a long arc
  4. Damp electrodes or contamination on the joint faces Correct answer.

Explanation

Porosity is gas trapped in the weld, commonly caused by moisture in the electrode coating, oil, paint or rust on the joint faces. Drying electrodes and cleaning the joint prevent it. Correct storage and clean plate are the conditions that avoid porosity.

Question 49Engineering Craft Practice and Workshop Technology

A reamed hole is found to be oversize after reaming. Which practice is the most likely cause?

  1. Using a reamer with the correct cutting fluid and slow speed
  2. Drilling the hole slightly undersize before reaming
  3. Removing the reamer from the hole without stopping the spindle
  4. Feeding the reamer too fast and rotating it in the reverse direction Correct answer.

Explanation

Reamers cut on their chamfered ends and must be fed steadily and rotated in the cutting direction only. Reversing rotation or forcing the feed causes the reamer to chatter and cut oversize. The hole should be drilled undersize and the reamer withdrawn while still rotating forward.

Question 50Engineering Craft Practice and Workshop Technology

A precision component is to be held for a light milling cut and must not be distorted by clamping. The most suitable work-holding method is to:

  1. clamp it to the table using a strap and packing arranged over a solid part of the work Correct answer.
  2. clamp across a thin unsupported section of the work
  3. grip it in a machine vice with maximum jaw pressure
  4. hold it by hand against the cutter

Explanation

Clamping with a strap and packing arranged over a solid part of the work holds it securely without squeezing thin sections out of shape. Maximum vice pressure and clamping across unsupported thin walls both distort the work. Hand-holding against a cutter is dangerous.