I85PREP
⌘ K
BTEB Machinist study materials
BTEB Machinist study resources

BTEB Machinist practice questions

One question at a time. Build your BTEB Machinist 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 1Machining Fundamentals and Workshop Safety

Which personal protective equipment is most important to wear while operating a centre lathe to protect the eyes from flying chips?

  1. Ear plugs
  2. Safety goggles Correct answer.
  3. Steel-toe boots
  4. Leather apron

Explanation

Safety goggles shield the eyes from hot metal chips and coolant splashes, which are the most common eye hazards at a lathe. Other PPE protects different body areas but does not guard the eyes.

Question 2Machining Fundamentals and Workshop Safety

On a standard centre lathe, which part carries the tool and can be moved longitudinally along the bed?

  1. The headstock
  2. The saddle Correct answer.
  3. The lead screw
  4. The tailstock

Explanation

The saddle slides along the bed ways and supports the cross-slide and tool post, giving longitudinal feed to the cutting tool. It is the carriage component that travels parallel to the spindle axis.

Question 3Machining Fundamentals and Workshop Safety

What is the main purpose of a centre drill when preparing a workpiece on a lathe?

  1. To enlarge an existing hole to an accurate diameter
  2. To produce a small pilot hole with a conical seat for supporting the work Correct answer.
  3. To cut internal threads in a bore
  4. To face the end of the workpiece square

Explanation

A centre drill combines a short stiff drill with a countersink, creating a pilot hole and a 60-degree seat that locates a lathe centre. This lets long work be supported by the tailstock without wandering.

Question 4Machining Fundamentals and Workshop Safety

Which property makes high-speed steel a popular material for lathe cutting tools?

  1. It has the lowest cost of all tool materials
  2. It melts at a lower temperature than aluminium
  3. It retains hardness at the elevated temperatures produced by cutting Correct answer.
  4. It is softer than mild steel for easier sharpening

Explanation

High-speed steel keeps its hardness even when it becomes red-hot during cutting, which allows higher speeds than plain carbon steel. This hot hardness is the key reason it is widely used for drills and form tools.

Question 5Machining Fundamentals and Workshop Safety

What does the abbreviation RPM represent when setting a lathe spindle speed?

  1. Radius per millimetre
  2. Revolutions per minute Correct answer.
  3. Roughness per micron
  4. Reduction per minute

Explanation

RPM stands for revolutions per minute, the number of complete turns the spindle makes in one minute. It is the basic setting used to control cutting speed on a lathe.

Question 6Machining Fundamentals and Workshop Safety

Which fire extinguisher type is suitable for a small fire involving lubricating oil near a machine?

  1. Sand only for metal fires
  2. Carbon dioxide only for electrical fires
  3. Water
  4. Foam or dry powder Correct answer.

Explanation

Oil fires are class B flammable-liquid fires, and foam or dry powder extinguishers smother them effectively. Water spreads burning oil and must never be used on such fires.

Question 7Machining Fundamentals and Workshop Safety

Why should long hair be tied back and loose sleeves rolled up before working at a machine?

  1. To reduce the noise level
  2. To prevent them being caught in rotating parts Correct answer.
  3. To improve the operator's posture
  4. To keep clothing clean of oil

Explanation

Rotating chucks, shafts and drills can seize loose clothing or hair and pull the operator into the machine, causing severe injury. Securing them removes this entanglement hazard.

Question 8Machining Fundamentals and Workshop Safety

Which measuring instrument is most suitable for checking the outside diameter of a turned shaft to 0.01 mm?

  1. Micrometer Correct answer.
  2. Vernier height gauge
  3. Try square
  4. Steel rule

Explanation

A micrometer reads outside diameters to 0.01 mm with high accuracy and is the standard tool for checking turned shafts. A steel rule is far too coarse for this tolerance.

Question 9Machining Fundamentals and Workshop Safety

A mild steel bar of 40 mm diameter is to be turned at a cutting speed of 30 m/min. Which spindle speed is closest?

  1. 24 rpm
  2. 2400 rpm
  3. 120 rpm
  4. 240 rpm Correct answer.

Explanation

Spindle speed equals cutting speed divided by the circumference, so 30 divided by (pi times 0.040) gives about 239 rpm. Rounding to 240 rpm is the practical setting.

Question 10Machining Fundamentals and Workshop Safety

When turning a workpiece held only in a three-jaw chuck, why should the unsupported length be kept short?

  1. Long overhang causes vibration and deflection of the work Correct answer.
  2. The tailstock cannot reach long work
  3. Long work heats up less
  4. The chuck cannot grip long bars

Explanation

A long unsupported overhang bends under cutting force, producing chatter, poor finish and inaccurate diameter. Supporting it with a tailstock centre or steady reduces this deflection.

Question 11Machining Fundamentals and Workshop Safety

What is the effect of increasing feed rate while keeping spindle speed constant?

  1. Cutting temperature always falls
  2. The chip becomes thicker and surface finish generally becomes rougher Correct answer.
  3. The chip becomes thinner and finish improves
  4. Tool life always increases

Explanation

Feed controls how far the tool advances per revolution, so a higher feed produces a thicker chip and a coarser surface finish. Cutting forces and temperature usually rise as well.

Question 12Machining Fundamentals and Workshop Safety

Which thread form is defined by a 60-degree included angle and is the standard for general fastening?

  1. ISO metric thread Correct answer.
  2. Square thread
  3. Buttress thread
  4. Acme thread

Explanation

The ISO metric thread has a 60-degree included angle and is the standard fastening thread worldwide. Its symmetrical form gives good strength and ease of manufacture.

Question 13Machining Fundamentals and Workshop Safety

Why is a cutting fluid applied during a turning operation on steel?

  1. To cool the tool and work and to reduce friction at the cutting edge Correct answer.
  2. To slow the spindle automatically
  3. To increase the hardness of the workpiece
  4. To make the chip thicker

Explanation

Cutting fluid carries heat away from the tool and workpiece and lubricates the contact zone, reducing friction and wear. This improves tool life and surface finish.

Question 14Machining Fundamentals and Workshop Safety

A workpiece must be set so that its axis runs true with the lathe spindle. Which method checks this for a bar in a four-jaw chuck?

  1. Listening for noise while the machine runs
  2. Tapping the work with a hammer while it spins
  3. Measuring the bar length with a steel rule
  4. Rotating the work by hand and comparing readings of a dial test indicator Correct answer.

Explanation

A dial test indicator mounted on the carriage contacts the rotating surface, and any runout shows as needle movement. Adjusting the four jaws reduces the reading until the bar runs true.

Question 15Machining Fundamentals and Workshop Safety

Why must a machine be isolated from the power supply before a chuck is changed?

  1. To cool the motor
  2. To reset the spindle bearings
  3. To prevent accidental spindle start-up that could injure the operator Correct answer.
  4. To clear metal chips from the tray

Explanation

Locking off the supply removes the risk that someone starts the spindle while hands are on the chuck. Isolation is a fundamental lockout practice for any work near rotating parts.

Question 16Machining Fundamentals and Workshop Safety

What is the purpose of a reamer in hole production?

  1. To cut a thread in a hole
  2. To counterbore a seat for a bolt head
  3. To start a new hole in solid metal
  4. To size and finish an existing hole accurately Correct answer.

Explanation

A reamer removes a small amount of material from a pre-drilled hole to bring it to an accurate size with a fine finish. It cannot create a hole from solid material.

Question 17Machining Fundamentals and Workshop Safety

A 50 mm diameter bar is turned at 200 rpm. What is the approximate cutting speed?

  1. 100 m/min
  2. 3 m/min
  3. 31 m/min Correct answer.
  4. 10 m/min

Explanation

Cutting speed equals pi times diameter in metres times rpm, so pi times 0.050 times 200 gives about 31 m/min. This confirms the standard relationship between diameter, rpm and surface speed.

Question 18Machining Fundamentals and Workshop Safety

Which condition most directly indicates that a lathe tool is worn and needs regrinding?

  1. A smooth surface finish
  2. Excessive flank wear land and a bright rubbing mark on the work Correct answer.
  3. A steady chip colour
  4. A constant spindle noise

Explanation

A growing wear land on the flank and a polished rub mark indicate the cutting edge has dulled and is rubbing rather than cutting. Continued use raises forces and damages surface finish.

Question 19Machining Fundamentals and Workshop Safety

A workpiece is 120 mm long and held in a chuck with 60 mm protruding. Which measure improves rigidity before turning?

  1. Support the free end with a tailstock centre Correct answer.
  2. Remove the chuck jaws
  3. Increase the depth of cut at once
  4. Raise the spindle speed to maximum

Explanation

Supporting the overhanging end with a centre halves the unsupported span, greatly reducing deflection and chatter. This allows heavier cuts while holding accuracy.

Question 20Machining Fundamentals and Workshop Safety

In a taper turning operation using the compound slide, the angle set on the slide corresponds to which value?

  1. The clearance angle of the tool
  2. Half the included angle of the taper Correct answer.
  3. The full included angle of the taper
  4. The thread angle

Explanation

The compound slide is swivelled to the half-angle because the tool travels along one side of the taper, not across the full included angle. Setting the full angle would produce a taper twice as steep.

Question 21Machining Fundamentals and Workshop Safety

Why is a four-jaw independent chuck preferred over a three-jaw chuck for a heavy, irregular casting?

  1. It spins faster than a three-jaw chuck
  2. It needs no dial indicator for any job
  3. It automatically balances the workpiece
  4. Each jaw can be set independently to grip an odd shape and centre it accurately Correct answer.

Explanation

Independent jaws can each be positioned to suit an irregular outline and adjusted to centre the work precisely. A three-jaw scroll chuck only suits round or hexagonal work of consistent shape.

Question 22Machining Fundamentals and Workshop Safety

A drilled hole measures 19.90 mm and must be reamed to 20.00 mm. Which practice gives the best result?

  1. Drill 20.50 mm and ream to remove the excess
  2. Drill exactly 20.00 mm and ream with no allowance
  3. Drill 19.90 mm and ream dry at high speed
  4. Drill about 0.2 mm undersize, then ream with adequate lubricant at low speed and steady feed Correct answer.

Explanation

Reamers need a small allowance, typically 0.1 to 0.3 mm, to cut cleanly without rubbing or chattering. Low speed, steady feed and lubricant produce an accurate size and fine finish.

Question 23Machining Fundamentals and Workshop Safety

When single-point threading on a lathe, why is the half-nut engaged only at positions indicated by the threading dial?

  1. To keep the tool cool
  2. To ensure the tool re-enters the same helical groove on each pass Correct answer.
  3. To reduce spindle speed automatically
  4. To prevent the lead screw from turning

Explanation

The threading dial shows when the carriage position matches the lead screw rotation, so engaging there makes the tool follow the existing groove. Engaging at random points cuts a new groove and ruins the thread.

Question 24Machining Fundamentals and Workshop Safety

A turned surface shows regular evenly spaced ridges along the work. Which cause is most likely?

  1. Feed marks from the tool advance per revolution Correct answer.
  2. A worn tailstock centre
  3. A loose tool post bolt
  4. Incorrect coolant concentration

Explanation

Evenly spaced helical ridges matching the feed per revolution are the normal footprint of the tool nose. Reducing feed or using a larger nose radius makes them finer.

Question 25Machining Fundamentals and Workshop Safety

Why is a lower cutting speed generally recommended when turning a hard alloy with a carbide tool compared with mild steel?

  1. Hard alloys conduct heat away faster, so less speed is needed
  2. Higher hardness generates more heat at the edge, so speed is reduced to control temperature and wear Correct answer.
  3. Carbide cannot cut hard alloys at any speed
  4. Lower speed increases the hardness of the alloy

Explanation

Harder workpieces require more cutting energy, raising edge temperature and accelerating wear, so speed is reduced to keep temperature within the tool's limit. This balances productivity against tool life.

Question 26Machining Fundamentals and Workshop Safety

Which property of a material describes its ability to be permanently stretched into wire without breaking?

  1. Brittleness
  2. Elastic limit
  3. Hardness
  4. Ductility Correct answer.

Explanation

Ductility is the property that allows a metal to be drawn out into wire or stretched permanently under tension without fracture. It depends on the material's crystal structure and is why low-carbon steel can be drawn into wire while cast iron cannot.

Question 27Machining Fundamentals and Workshop Safety

On a metric vernier calliper, the main scale is graduated in millimetres and the vernier has 50 divisions spanning 49 mm. What is the least count?

  1. 0.1 mm
  2. 0.02 mm Correct answer.
  3. 0.05 mm
  4. 0.5 mm

Explanation

Least count equals the smallest main-scale division divided by the number of vernier divisions, so 1 mm divided by 50 gives 0.02 mm. This follows because 50 vernier divisions cover 49 mm of the main scale, a difference of 1 mm spread over 50 divisions.

Question 28Machining Fundamentals and Workshop Safety

Which safety practice applies when filing a workpiece on a bench?

  1. Press the file back and forth on the return stroke
  2. Fit a handle to the file and cut away from the body Correct answer.
  3. Use the file without a handle for better feel
  4. Clean the file with the palm of the hand

Explanation

A file should always carry a sound handle because the tang can pierce the hand if the file jams or slips. Strokes are made away from the body so that a slip carries the hand clear of sharp edges.

Question 29Machining Fundamentals and Workshop Safety

In a drilling machine, what is the main purpose of a drill chuck key?

  1. To tighten the jaws of the chuck onto the drill shank Correct answer.
  2. To adjust the depth stop on the quill
  3. To align the table with the spindle axis
  4. To lock the spindle during a feed change

Explanation

The chuck key engages the bevel gear in the chuck body so the jaws can be tightened or released around the drill shank. The key must be removed immediately after use because a key left in the chuck can be thrown out at high speed.

Question 30Machining Fundamentals and Workshop Safety

Which unit is used to express cutting speed in metric machining practice?

  1. Metres per minute Correct answer.
  2. Millimetres per revolution
  3. Millimetres per minute
  4. Revolutions per minute

Explanation

Cutting speed is the rate at which the workpiece surface passes the tool, expressed in metres per minute in metric practice. Spindle speed is expressed in revolutions per minute, feed in millimetres per revolution, and feed rate in millimetres per minute.

Question 31Machining Fundamentals and Workshop Safety

Which statement correctly describes the difference between a shaper and a planer?

  1. The shaper moves the work past a stationary tool, while the planer moves the tool over stationary work
  2. The shaper moves the tool over stationary work, while the planer moves the work past a stationary tool Correct answer.
  3. Both machines move the tool while the work remains clamped and stationary
  4. Both machines move the work while the tool remains fixed in one position

Explanation

On a shaper the ram carries the single-point tool back and forth while the workpiece is clamped to the table. On a planer the table reciprocates with the workpiece while the tool head stays essentially stationary, which suits very large workpieces.

Question 32Machining Fundamentals and Workshop Safety

What does the pitch of a metric screw thread represent?

  1. The total length of the threaded portion
  2. The angle between the thread flanks
  3. The diameter measured over the crests of the thread
  4. The axial distance between corresponding points on adjacent threads Correct answer.

Explanation

Pitch is the axial distance from a point on one thread to the corresponding point on the next thread. For a single-start thread it equals the lead, while for a multi-start thread the lead is the pitch multiplied by the number of starts.

Question 33Machining Fundamentals and Workshop Safety

Which abrasive material is normally used for grinding wheels intended for hardened steel?

  1. Boron carbide
  2. Aluminium oxide Correct answer.
  3. Silicon carbide
  4. Diamond

Explanation

Aluminium oxide grains are tough and retain sharp edges under heat, making them the standard choice for grinding hardened carbon and alloy steels. Silicon carbide is more friable and is generally reserved for cast iron, non-ferrous metals and carbide tooling.

Question 34Machining Fundamentals and Workshop Safety

A rectangular block is to be marked out on a surface plate. Which combination of tools is appropriate for scribing a line parallel to a finished edge?

  1. Surface plate, V-block and centre punch
  2. Surface plate, dividers and radius gauge
  3. Surface plate, vernier height gauge and scriber Correct answer.
  4. Surface plate, feeler gauge and steel rule

Explanation

A vernier height gauge with a scriber, used on a surface plate, allows lines to be set at a measured height above the datum face. The block rests on the plate so the scribed line is parallel to the plate surface and hence to the finished edge.

Question 35Machining Fundamentals and Workshop Safety

Why is a centre drill used before a standard twist drill when drilling a hole in a lathe?

  1. It eliminates the need for cutting fluid
  2. It cuts the hole to final size in one pass
  3. It produces a conical seat that guides the drill and reduces wander Correct answer.
  4. It removes the need for a pilot hole

Explanation

A centre drill combines a short stiff pilot with a countersink, creating a conical seat that steadies the following twist drill and keeps it on the axis. This reduces drill wander and produces a hole that is more likely to be concentric with the spindle.

Question 36Machining Fundamentals and Workshop Safety

In a metal-cutting operation, what does the term 'built-up edge' describe?

  1. A raised burr left on the machined surface
  2. Work material welded to the tool face near the cutting edge Correct answer.
  3. Metal folded over at the end of a bar during turning
  4. A hardened layer formed beneath the machined surface

Explanation

A built-up edge forms when work material pressure-welds to the tool face under high temperature and pressure and then grows and breaks away cyclically. It causes poor surface finish and dimensional variation, and is reduced by suitable cutting speeds and cutting fluid.

Question 37Machining Fundamentals and Workshop Safety

Which property makes high-speed steel a popular material for drills and milling cutters?

  1. It has very low thermal conductivity
  2. It retains hardness at elevated cutting temperatures Correct answer.
  3. It resists corrosion better than any other tool steel
  4. It is softer than carbon steel when hot

Explanation

High-speed steel contains tungsten, molybdenum, vanadium and chromium, which give it red hardness, meaning it keeps its cutting hardness even when it becomes hot. This allows higher cutting speeds than plain carbon steel tools can withstand.

Question 38Machining Fundamentals and Workshop Safety

What is the function of the flutes on a twist drill?

  1. To hold the drill in the chuck jaws
  2. To reduce the overall length of the drill
  3. To centre the drill in the chuck
  4. To provide cutting edges and allow chips to escape Correct answer.

Explanation

The helical flutes form the cutting lips at the point and provide a path for chips to travel up and out of the hole. Chip clearance is essential because packed chips generate heat and can break the drill.

Question 39Machining Fundamentals and Workshop Safety

A lathe is set to turn a 60 mm diameter bar at a spindle speed of 250 rpm. Which cutting speed does this correspond to, to the nearest whole metre per minute?

  1. 150 m/min
  2. 15 m/min
  3. 94 m/min
  4. 47 m/min Correct answer.

Explanation

Cutting speed equals pi times diameter in metres times spindle speed, so 3.142 times 0.060 times 250 gives about 47 m/min. The diameter must be converted to metres before multiplying by revolutions per minute.

Question 40Machining Fundamentals and Workshop Safety

Which holding device is most suitable for gripping a round workpiece that must be rotated between operations while maintaining concentricity?

  1. Angle plate
  2. V-block clamped to the table
  3. Machine vice
  4. Three-jaw self-centring chuck Correct answer.

Explanation

A three-jaw self-centring chuck grips round work and centres it automatically as the jaws move together, so a re-chucked part stays close to the axis. Machine vices, V-blocks and angle plates hold work stationary on a table and do not rotate it.

Question 41Machining Fundamentals and Workshop Safety

During a turning operation the workpiece begins to vibrate and the surface shows chatter marks. Which action is most appropriate?

  1. Reduce the spindle speed to zero and restart at the same setting
  2. Increase the depth of cut to damp the vibration
  3. Remove the tailstock support to free the work
  4. Reduce the overhang, increase rigidity and adjust speed and feed Correct answer.

Explanation

Chatter arises from insufficient rigidity in the work, tool or setup, so shortening the overhang, supporting the free end and selecting a speed and feed that avoid resonance are the standard remedies. Increasing the depth of cut or removing support usually makes vibration worse.

Question 42Machining Fundamentals and Workshop Safety

Which statement best explains why cutting fluid is filtered and replaced periodically in a machine sump?

  1. Chips and bacteria build up and reduce cooling and cause odour Correct answer.
  2. The fluid loses its colour and cannot be seen
  3. The fluid gradually turns into a solid lubricant
  4. The fluid becomes more flammable with use

Explanation

Sworf and fines carried into the sump clog filters and harbour bacteria, which degrade the fluid, reduce its cooling performance and create unpleasant odours. Regular filtration and replacement keep heat transfer effective and protect operators from skin irritation.

Question 43Machining Fundamentals and Workshop Safety

What is the purpose of the tailstock when turning a long slender shaft between centres?

  1. To apply the feed to the carriage
  2. To measure the length of the workpiece
  3. To support the free end and prevent deflection Correct answer.
  4. To hold the cutting tool

Explanation

A long slender shaft tends to deflect away from the tool under cutting force, so supporting the free end with the tailstock centre keeps it rigid and accurate. This is why work between centres is preferred for long shafts.

Question 44Machining Fundamentals and Workshop Safety

A milling cutter is to be used on a vertical milling machine. Which statement about climb milling compared with conventional milling is correct?

  1. Climb milling feeds the work in the same direction as cutter rotation, giving a better finish where backlash is eliminated Correct answer.
  2. Climb milling can only be done on a lathe
  3. Climb milling removes material only on the up-stroke of the table
  4. Climb milling feeds the work against cutter rotation and is always safer on older machines

Explanation

In climb milling the work is fed so that the cutter teeth move in the same direction as the feed at the point of contact, which tends to push the work down and produces a cleaner finish. It requires a machine with backlash elimination, otherwise the cutter can drag the work and damage the setup.

Question 45Machining Fundamentals and Workshop Safety

Which instrument is used to check that a machine table surface is horizontal?

  1. Radius gauge
  2. Micrometer
  3. Vernier height gauge
  4. Precision spirit level Correct answer.

Explanation

A precision spirit level placed on the table shows whether the surface is horizontal by the position of the bubble in its vial. It is a standard tool for levelling machines and checking table flatness during installation.

Question 46Machining Fundamentals and Workshop Safety

Which condition is the main reason for using a coolant when tapping a blind hole in steel?

  1. To lubricate the flutes and help flush chips from the hole Correct answer.
  2. To enlarge the hole slightly
  3. To increase the pitch of the thread
  4. To harden the tap during cutting

Explanation

Tapping generates high friction along the flutes and produces chips that must escape from a blind hole, so a suitable lubricant reduces friction and helps carry chips out. This lowers the risk of tap breakage and torn threads.

Question 47Machining Fundamentals and Workshop Safety

A workpiece is clamped in a machine vice for milling. Why should the work be tapped down with a soft mallet before final tightening?

  1. To reduce the length of the workpiece
  2. To cool the workpiece before cutting
  3. To increase the hardness of the work surface
  4. To seat the work firmly on the vice jaws and parallels Correct answer.

Explanation

Tapping the work down ensures it rests fully on the parallels and jaw faces, removing any gap that would let it spring or vibrate during cutting. Final tightening is then done so the work stays seated and the machined surface is parallel.

Question 48Machining Fundamentals and Workshop Safety

Which statement about the safe use of an abrasive cut-off wheel is correct?

  1. The wheel may be used without a guard if the operator wears goggles
  2. The work may be held by hand during cutting
  3. The wheel guard must be in place and the work securely clamped before starting Correct answer.
  4. The wheel speed rating may be exceeded for thin sections

Explanation

An abrasive wheel can burst if abused, so the guard must cover the wheel and the work must be clamped so it cannot be grabbed. Personal protection alone does not replace the guard or proper clamping.

Question 49Machining Fundamentals and Workshop Safety

What is the purpose of a limit switch on the guard of a machine tool?

  1. To limit the maximum spindle speed
  2. To lubricate the machine automatically
  3. To stop the machine if the guard is opened while it is running Correct answer.
  4. To measure the length of the workpiece

Explanation

A limit switch linked to the guard interrupts the control circuit when the guard is opened, stopping the machine before the operator can reach moving parts. This interlock is a key machine-guarding safety measure.

Question 50Machining Fundamentals and Workshop Safety

A hole is to be drilled and then bored to a precise diameter on a lathe. Why is boring preferred to simply drilling to size?

  1. Boring is faster than drilling in every case
  2. Boring removes less material than drilling
  3. Boring corrects position and size and can produce a straight, accurate hole Correct answer.
  4. Boring does not require the work to be held in a chuck

Explanation

A drill tends to follow its own path and can produce an oversized or off-centre hole, whereas a boring tool is supported on a rigid bar and can correct both size and alignment. Boring also allows fine adjustment to reach a precise diameter.