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MMAW NC II practice questions

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Question 1Workplace safety, 5S, and environmental regulations

Under the Philippine OSH law (RA 11058) and its IRR, which of the following best describes the employer's duty regarding a safety and health committee in a welding workshop?

  1. The committee is optional and may be replaced entirely by the safety officer's personal logbook
  2. The committee is required only when the shop employs 50 or more workers or is declared high-risk, and must be organized with worker representatives Correct answer.
  3. The committee is required only after a serious accident has already occurred in the shop
  4. The committee is formed only by the client's safety inspector during an audit visit

Explanation

RA 11058 and DOLE Department Order 198-18 require covered establishments, including those with 50 or more workers or those classified as high-risk, to organize a Safety and Health Committee with management and worker representatives. Welding shops handling hot work and compressed gas are commonly treated as high-risk, so the committee must be functional and documented.

Question 2Workplace safety, 5S, and environmental regulations

In the 5S system applied to a welding bay, what does the step 'Seiso' primarily require workers to do?

  1. Schedule periodic audits and post the results on a visual board
  2. Clean the work area and equipment so that leaks, cracks, and loose fittings are exposed Correct answer.
  3. Assign a fixed location and label to every jig, clamp, and electrode holder
  4. Sort tools and remove items that are not needed for the current welding job

Explanation

Seiso means cleaning as inspection: sweeping, wiping, and checking equipment so that abnormal conditions such as oil leaks, cracked insulation, or loose gas fittings become visible. Cleaning is not cosmetic; it is a method of detecting deterioration early.

Question 3Workplace safety, 5S, and environmental regulations

A welder must store oxygen and acetylene cylinders in the shop's gas storage area. Which practice complies with standard compressed-gas safety rules?

  1. Store all cylinders together in a closed wooden cabinet next to the welding bay
  2. Lay acetylene cylinders horizontally on the floor to save vertical space and prevent tipping
  3. Store oxygen and acetylene cylinders side by side with their regulators connected and valves open
  4. Keep oxygen and acetylene cylinders separated by at least 6 meters, or by a noncombustible barrier at least 1.5 meters high Correct answer.

Explanation

Standard practice requires fuel-gas and oxidizer cylinders to be separated by at least 6 meters or by a noncombustible barrier at least 1.5 meters high with a fire-resistance rating. This separation prevents a fire involving one gas from immediately involving the other.

Question 4Workplace safety, 5S, and environmental regulations

During shielded metal arc welding, a helper stands nearby watching the arc without eye protection. What is the main hazard the helper faces?

  1. Hearing damage from the arc's high-frequency current
  2. Ultraviolet radiation exposure that can cause arc eye and skin burns Correct answer.
  3. Electric shock from the workpiece ground clamp
  4. Carbon monoxide poisoning from the electrode coating

Explanation

The welding arc emits intense ultraviolet and infrared radiation that can inflame the cornea, causing arc eye, and can burn exposed skin. Bystanders within the arc's vicinity need appropriate eye and skin protection or a screened barrier.

Question 5Workplace safety, 5S, and environmental regulations

A welding shop uses the 5S color-coding system. Which action best reflects 'Seiton' in the storage of filler metals?

  1. Sweeping the floor around the rod oven at the end of each shift
  2. Dedicating labeled racks by electrode class and returning each rod to its correct slot after use Correct answer.
  3. Discarding all electrodes whose packaging is dusty and unreadable
  4. Assigning one worker to remind others to follow the rack rules

Explanation

Seiton is about a place for everything and everything in its place: designating and labeling storage so items are easy to find and return. A labeled rack organized by electrode classification puts that principle into practice.

Question 6Workplace safety, 5S, and environmental regulations

Which of the following is the correct first response when a welding fire starts in a small waste bin and the shop has a dry chemical extinguisher nearby?

  1. Spray water from a bucket onto the burning bin to cool the flames
  2. Open all windows and continue welding so the smoke clears faster
  3. Wait several minutes to see whether the fire goes out on its own
  4. Sound the alarm, then use the extinguisher with the PASS technique while keeping an exit behind you Correct answer.

Explanation

The correct sequence is to raise the alarm first, then attack a small fire only if trained and safe, using PASS: pull, aim, squeeze, sweep, while keeping a clear escape route. Water is unsafe on many electrical or chemical fires common in a shop.

Question 7Workplace safety, 5S, and environmental regulations

Under Philippine environmental rules, how should a welding shop dispose of spent welding electrodes and grinding dust that may contain heavy metals?

  1. Burn them in an open pit to reduce volume before disposal
  2. Bury them in the vacant lot behind the shop to avoid hauling costs
  3. Segregate them as hazardous waste and turn them over to an accredited hazardous-waste transporter with a manifest Correct answer.
  4. Mix them with ordinary shop refuse so the municipal collector can haul them away

Explanation

RA 6969 and its implementing rules classify wastes containing heavy metals as hazardous and require segregation, proper labeling, and turnover to an accredited transporter documented by a waste manifest. Ordinary municipal collection, open dumping, and open burning are prohibited for such waste.

Question 8Workplace safety, 5S, and environmental regulations

A welder is about to work inside a confined tank. Which control set is required before entry is allowed?

  1. Leaving the tank open overnight so the air naturally clears without testing
  2. Atmospheric testing, forced ventilation, an entry permit, a standby attendant, and retrieval equipment Correct answer.
  3. A single worker entering alone with a flashlight and a mobile phone
  4. Wearing a dust mask and proceeding immediately after the tank is drained

Explanation

Confined-space entry requires pre-entry atmospheric testing for oxygen, flammables, and toxic gases, plus ventilation, a permit, a standby attendant outside, and retrieval or rescue equipment. Welding inside a tank adds fume and shielding-gas displacement hazards.

Question 9Workplace safety, 5S, and environmental regulations

What is the primary purpose of a hot-work permit in a fabrication shop?

  1. To document that fire hazards were assessed, fire watch assigned, and combustible materials controlled before welding begins Correct answer.
  2. To certify that the welder's certification card is still valid for the process
  3. To authorize overtime work on the welding machine
  4. To record the welder's daily production output for payroll purposes

Explanation

A hot-work permit verifies that the area has been assessed, combustibles removed or protected, a fire watch posted, and extinguishing equipment provided before any spark-producing task. It is a fire-prevention control, not a payroll, certification, or scheduling document.

Question 10Workplace safety, 5S, and environmental regulations

Which welding process hazard is best controlled by local exhaust ventilation placed close to the arc?

  1. Welding fume and metal oxide particulate inhaled by the welder Correct answer.
  2. Spatter burning the welder's gloves
  3. Noise from the power source's cooling fan
  4. Arc flash reaching the welder's helmet

Explanation

Local exhaust ventilation captures fume and fine particulate at the source before it reaches the welder's breathing zone. It is the preferred engineering control for welding fume, especially with processes that generate high fume levels.

Question 11Workplace safety, 5S, and environmental regulations

A welding machine's secondary cable and electrode holder show cracked insulation and exposed copper. What is the correct action?

  1. Tag the equipment out of service and replace the damaged cable or holder before further use Correct answer.
  2. Lower the welding current so the exposed conductor stays cool
  3. Continue welding but wear two pairs of gloves for extra protection
  4. Wrap the exposed section with ordinary masking tape and continue welding

Explanation

Damaged insulation on welding leads or holders creates shock and arc-flash risk and must be repaired or replaced. Lockout and tagging the equipment out of service prevents use until the defect is corrected.

Question 12Workplace safety, 5S, and environmental regulations

Which practice best demonstrates 'Shitsuke' (sustaining) in a welding shop's 5S program?

  1. Removing all unused fixtures from the shelves during a one-time cleanup
  2. Conducting regular self-audits and correcting deviations so the first four S steps become daily habit Correct answer.
  3. Installing additional storage cabinets to hold more tools
  4. Painting all machine guards a bright color for visibility

Explanation

Shitsuke is the discipline step: maintaining the gains of sorting, arranging, and cleaning through routine audits, correction, and habit. It is about consistency over time rather than one-time actions.

Question 13Workplace safety, 5S, and environmental regulations

A welder notices a small acetylene leak at a hose connection, detected by smell and a hiss. What is the safest immediate response?

  1. Tighten the connection with a wrench while the system stays pressurized
  2. Stop work, close the cylinder valve, ventilate the area, and check for ignition sources before repairing Correct answer.
  3. Ignore the leak if the flame at the torch still looks normal
  4. Light the torch to burn off the leaking gas so it does not accumulate

Explanation

A fuel-gas leak must be isolated at the source and the area ventilated while ignition sources are eliminated. Repair is done only after depressurizing, and acetylene fittings should never be tightened under pressure.

Question 14Workplace safety, 5S, and environmental regulations

Which of the following correctly describes the hierarchy of controls as applied to a welding task?

  1. Engineering controls are used only when PPE has already failed
  2. Administrative controls rank highest because they are the cheapest to implement
  3. Elimination and substitution rank above engineering controls, which rank above administrative controls and PPE Correct answer.
  4. PPE ranks first because it is issued directly to the welder

Explanation

The hierarchy of controls places elimination and substitution as most effective, followed by engineering controls, then administrative controls, with PPE as the last line of defense. PPE is essential but depends on correct use and does not remove the hazard.

Question 15Workplace safety, 5S, and environmental regulations

A welding shop generates used oil-soaked rags and empty paint cans. Which handling practice aligns with environmental regulations and good housekeeping?

  1. Store them in an open cardboard box near the welding bay for convenience
  2. Throw them into the general trash bin at the end of the shift
  3. Leave them on the floor to dry out before disposal
  4. Place them in covered, labeled containers for hazardous waste and keep them away from ignition sources Correct answer.

Explanation

Oil-soaked rags can self-heat and ignite, and empty containers may retain flammable residue, so both are managed as hazardous waste in covered, labeled containers away from ignition sources. This protects both workers and the environment.

Question 16Workplace safety, 5S, and environmental regulations

Which statement correctly distinguishes a hazard from a risk in a welding workplace?

  1. A hazard is the potential source of harm, while risk is the likelihood and severity of harm from exposure to it Correct answer.
  2. Hazard and risk are interchangeable terms with no practical difference
  3. Risk applies only to chemicals, while hazard applies only to machines
  4. A hazard is the probability of injury, while risk is the physical object causing it

Explanation

A hazard is anything with the potential to cause harm, such as welding fume, hot slag, or a compressed-gas cylinder. Risk combines the likelihood of exposure with the severity of the resulting harm, which is why the same hazard can carry different risk levels.

Question 17Workplace safety, 5S, and environmental regulations

What is the correct way to transport a compressed-gas cylinder short distances within a shop?

  1. Carry it over the shoulder with the valve open to release pressure
  2. Secure it upright on a cylinder trolley with the valve cap on and the regulator removed Correct answer.
  3. Drag it by the hose connected to the regulator
  4. Roll it on its base while holding the valve for balance

Explanation

Cylinders are moved upright on a proper trolley or cart, secured against tipping, with the valve protection cap in place and regulators removed. Rolling, carrying, or dragging by the hose risks valve damage and sudden gas release.

Question 18Workplace safety, 5S, and environmental regulations

A worker is assigned to weld on a steel structure at height using a scaffold. Which combination of controls is most appropriate?

  1. Working without fall protection because the scaffold is only two meters high
  2. Tying the safety lanyard to the scaffold's horizontal rail at foot level
  3. Standing on the top rail of the scaffold to reach the joint more easily
  4. Guardrails or a personal fall-arrest system anchored above, plus a tool lanyard and fire blanket below Correct answer.

Explanation

Fall protection at height requires guardrails or a properly anchored personal fall-arrest system with the anchor above the worker, plus control of dropped tools and sparks. Scaffold work also requires a competent person's inspection and safe access.

Question 19Workplace safety, 5S, and environmental regulations

Which action best reflects 'Seiri' when organizing a welding workbench at the start of a shift?

  1. Labeling each drawer with the name of the tool it should contain
  2. Wiping down the bench and checking the grinder's cord for damage
  3. Posting a checklist so the bench is inspected every morning
  4. Removing broken clamps, obsolete drawings, and unrelated tools so only what the job needs remains Correct answer.

Explanation

Seiri is sorting: separating what is needed from what is not and removing the unnecessary items from the work area. Clearing broken clamps, old drawings, and unrelated tools from the bench is a direct application.

Question 20Workplace safety, 5S, and environmental regulations

A welding shop must respond to the Philippine requirement on reporting work-related injuries. Which action is correct for a serious injury that requires hospitalization?

  1. Report it only to the client who commissioned the welded product
  2. Report the incident to DOLE through the prescribed work accident or injury report within the required period and keep an incident record Correct answer.
  3. Wait until the annual inspection before mentioning the injury
  4. Record it informally in the shift log and take no further action

Explanation

RA 11058 and its IRR require employers to maintain an accident and injury record and to report serious work-related injuries to DOLE within the prescribed period. Reporting supports investigation and prevention of recurrence.

Question 21Interpretation of technical drawings, diagrams, and work instructions

In a welding symbol, the arrow line points to the joint and the reference line carries the symbol. On which side of the reference line is the weld symbol placed to indicate a weld on the arrow side?

  1. Centered on the reference line
  2. On the tail of the symbol
  3. Above the reference line
  4. Below the reference line Correct answer.

Explanation

By convention in ISO and AWS welding symbols, a symbol drawn on the underside of the reference line denotes a weld made on the side the arrow touches, called the arrow side. Anything on the upper side refers to the other side of the joint. This placement rule lets the welder know which face of the joint receives the weld without extra notes.

Question 22Interpretation of technical drawings, diagrams, and work instructions

A drawing shows a fillet weld symbol with a dimension of 6 mm on the left of the symbol. What does the 6 mm represent?

  1. The root gap
  2. The throat thickness
  3. The leg size of the fillet Correct answer.
  4. The length of the weld

Explanation

For a fillet weld symbol, the number placed to the left of the symbol is the leg length (size) of the fillet. Weld length is shown to the right of the symbol, and throat thickness is not normally dimensioned directly on the symbol. Reading this correctly prevents undersized or oversized fillets.

Question 23Interpretation of technical drawings, diagrams, and work instructions

On an engineering drawing, a dimension line is drawn with a value of 25 and the general note states 'ALL DIMENSIONS IN MILLIMETRES'. What unit applies to the 25?

  1. Metres
  2. Inches
  3. Centimetres
  4. Millimetres Correct answer.

Explanation

The general note sets the default unit for all unmarked dimensions on that drawing, so 25 means 25 millimetres. Units are not repeated on every dimension when a general note covers them. Always confirm the unit note before cutting or fitting material.

Question 24Interpretation of technical drawings, diagrams, and work instructions

What does a first-angle projection symbol on a drawing tell the welder about the views?

  1. The views are arranged using first-angle projection conventions Correct answer.
  2. The drawing is a sketch without projection
  3. The part is shown in isometric only
  4. The drawing uses third-angle projection

Explanation

The projection symbol identifies which projection system the drawing uses, so the reader interprets the arrangement of views correctly. In first-angle projection the view placed to the right of the front view represents the left side of the object. Misreading the system leads to fabricating the part mirrored or reversed.

Question 25Interpretation of technical drawings, diagrams, and work instructions

A drawing note reads 'WELD ALL AROUND' next to a fillet weld symbol. What does this instruction require?

  1. The weld is ground flush after welding
  2. The weld is made in one pass only
  3. The weld continues around the entire joint perimeter Correct answer.
  4. The weld is made only on the arrow side

Explanation

The all-around symbol, a circle at the junction of the reference line and arrow, means the weld is applied continuously around the full perimeter of the joint. It is not limited to one face. This matters for estimating weld length and controlling distortion.

Question 26Interpretation of technical drawings, diagrams, and work instructions

In a set of orthographic views, a hidden feature is represented by which line type?

  1. A thick continuous line
  2. A dashed line Correct answer.
  3. A wavy freehand line
  4. A chain dotted line

Explanation

Hidden edges and outlines are drawn with dashed (broken) lines so features behind visible surfaces can be located. Thick continuous lines show visible outlines, and chain lines mark centre lines. Recognising line types helps the welder locate internal features before assembly.

Question 27Interpretation of technical drawings, diagrams, and work instructions

A detail drawing specifies a 60-degree included angle for a single-V butt joint with a 2 mm root gap. Why must the welder set this root gap before welding?

  1. To increase the leg length of the fillet
  2. To speed up the travel speed
  3. To allow full penetration at the root Correct answer.
  4. To reduce the heat input requirement

Explanation

The root gap and included angle together open the joint so the arc can reach the root, allowing full penetration and fusion through the thickness. Without the specified gap, the root may lack fusion. The gap is a joint preparation requirement, not a travel-speed control.

Question 28Interpretation of technical drawings, diagrams, and work instructions

A drawing shows a dimension of 40 mm with a tolerance of plus or minus 1 mm. A finished part measures 38.5 mm. How should this be judged?

  1. Rejected, above the upper limit
  2. Acceptable, within tolerance
  3. Rejected, below the lower limit Correct answer.
  4. Acceptable, above the upper limit

Explanation

The tolerance band runs from 39 mm to 41 mm, so a measurement of 38.5 mm falls below the lower limit and is out of tolerance. The part must be rejected or reworked. Reading tolerances correctly prevents passing undersized work.

Question 29Interpretation of technical drawings, diagrams, and work instructions

A welding procedure on the drawing specifies a 3 mm maximum mismatch (hi-lo) for a butt joint. What does mismatch refer to?

  1. The gap between the root faces
  2. The angle of the bevel
  3. The offset between the two plate surfaces at the joint Correct answer.
  4. The difference in plate thickness across the joint

Explanation

Mismatch, or hi-lo, is the offset between the internal or external surfaces of two members being joined, caused by fit-up error. Controlling it limits stress concentration and incomplete fusion. It is distinct from root gap and bevel angle.

Question 30Interpretation of technical drawings, diagrams, and work instructions

A drawing uses a section view with hatching. What does the direction and spacing of the hatch lines indicate?

  1. The direction of rolling
  2. The material that has been cut through Correct answer.
  3. The welding sequence to follow
  4. The location of hidden holes

Explanation

Hatching in a section view shows the solid material cut by the section plane, distinguishing it from voids and holes. Different hatch patterns or directions can identify different components in an assembly. Reading hatching helps the welder understand internal geometry.

Question 31Interpretation of technical drawings, diagrams, and work instructions

A drawing shows an isometric view with three axes at 30 degrees to the horizontal. What is the purpose of this view?

  1. To give a three-dimensional pictorial impression Correct answer.
  2. To show tolerances in detail
  3. To replace all orthographic views
  4. To show true shape of inclined faces

Explanation

An isometric view is a pictorial drawing that shows the object in three dimensions along three axes, helping the reader visualise the part. It does not show true shape of inclined faces and does not replace dimensioned orthographic views. It complements the detail views.

Question 32Interpretation of technical drawings, diagrams, and work instructions

A drawing shows a weld symbol with a number to the right of the fillet symbol, for example 6-100. What does the 100 represent?

  1. The number of passes
  2. The leg size in millimetres
  3. The electrode diameter
  4. The length of the weld in millimetres Correct answer.

Explanation

In fillet weld symbols, the figure to the right of the symbol gives the weld length. The figure to the left gives the leg size. Reading both correctly controls the amount of weld deposited and the fit-up required.

Question 33Interpretation of technical drawings, diagrams, and work instructions

A drawing calls up a 'square butt' joint with no bevel. For which thickness range is this joint preparation normally suitable?

  1. Pipe with compound bevels
  2. Thin plate where full penetration is achievable Correct answer.
  3. Thick plate requiring deep penetration
  4. Castings only

Explanation

A square butt joint has no groove preparation and is used on relatively thin material where the arc can penetrate the full thickness. On thick plate, a square edge would prevent full penetration and require a bevel or V preparation instead. The drawing note guides the fitter to prepare the edge accordingly.

Question 34Interpretation of technical drawings, diagrams, and work instructions

A drawing shows a datum feature marked with a datum symbol. Why is a datum important when reading the drawing?

  1. It marks the welding earth connection point
  2. It shows the heat treatment location
  3. It indicates the lifting point
  4. It establishes a reference from which dimensions are measured Correct answer.

Explanation

A datum is a reference feature from which related dimensions and tolerances are measured, ensuring consistent manufacture and inspection. It is not a connection or handling point. Recognising datums helps the welder maintain the correct position of features.

Question 35Interpretation of technical drawings, diagrams, and work instructions

A drawing note states 'BACK GOUGE TO SOUND METAL BEFORE WELDING SECOND SIDE'. What does this instruction require?

  1. Peening the weld surface
  2. Preheating the joint before welding
  3. Removing metal from the root until defect-free material is reached Correct answer.
  4. Grinding the weld cap flush

Explanation

Back gouging removes material from the reverse side of a welded joint until sound, defect-free metal is exposed, so the second side can be welded with full penetration. It is not the same as grinding the cap flush or preheating. Following this note prevents root defects being trapped.

Question 36Interpretation of technical drawings, diagrams, and work instructions

A drawing specifies a weld symbol with a triangle and a flag at the top of the reference line. What does the flag indicate?

  1. The weld requires post-weld heat treatment
  2. The weld is a temporary tack
  3. The weld is to be made in the shop
  4. The weld is to be made on site Correct answer.

Explanation

A flag at the junction of the reference line and arrow indicates a field weld, meaning the weld is made at the site of final assembly rather than in the fabrication shop. This affects planning, access and inspection. It is distinct from heat treatment or tack notes.

Question 37Interpretation of technical drawings, diagrams, and work instructions

A drawing shows a compound bevel on a thick pipe joint. Why would a compound bevel be specified instead of a simple single bevel?

  1. To remove the need for inspection
  2. To eliminate the need for a root gap
  3. To allow welding without preheat
  4. To reduce weld metal volume while maintaining root access Correct answer.

Explanation

A compound bevel uses a steeper angle near the root and a shallower angle further out, which maintains root access while reducing the cross-sectional area of the groove. This lowers weld metal consumption and distortion compared with a simple bevel. It does not remove the need for root gap, preheat or inspection.

Question 38Interpretation of technical drawings, diagrams, and work instructions

A fabrication drawing shows two views that appear inconsistent: the front view shows a hole at 30 mm from the left edge, while the plan view shows it at 35 mm. What is the correct action before cutting?

  1. Use the larger value to be safe
  2. Query the discrepancy with the drawing issuer before proceeding Correct answer.
  3. Proceed using the front view only
  4. Average the two values

Explanation

When views conflict, the drawing is ambiguous and the welder or fitter must not guess. The correct action is to raise a query with the drawing issuer so a controlled correction is issued. Averaging or choosing a value risks fabricating a non-conforming part.

Question 39Interpretation of technical drawings, diagrams, and work instructions

A drawing shows a weld symbol with a concave contour symbol above the fillet triangle. What does this require of the finished weld?

  1. The weld face is to be concave Correct answer.
  2. The weld face is to be flat
  3. The weld face is to be convex
  4. The weld is to be ground flush

Explanation

A concave finishing symbol above the fillet indicates the weld face should be dressed to a concave profile, often to improve fatigue performance or fit. Flat and convex contours have their own symbols. Flush grinding is shown by a separate finish symbol.

Question 40Interpretation of technical drawings, diagrams, and work instructions

A drawing specifies a weld that is to be inspected by ultrasonic testing after a specified delay. Why does the drawing include a delay time before inspection?

  1. To allow paint to cure
  2. To allow the weld to cool so handling is safe
  3. To allow hydrogen to diffuse and delayed cracking to appear Correct answer.
  4. To allow the welder to complete other work

Explanation

For some steels, inspection is delayed so that hydrogen can diffuse and any delayed cracking becomes detectable. Inspecting too early may miss cracks that appear later. The delay is a quality control requirement, not a handling or scheduling convenience.

Question 41Hand tools, measuring instruments, and precision measurement

A steel rule is used to measure a workpiece in a machine shop. Which reading practice gives the most reliable result?

  1. Read the scale while the rule is tilted toward the light
  2. Read the scale from one side of the rule at a low angle
  3. Read the scale at eye level directly above the graduation mark Correct answer.
  4. Read the scale after wiping the rule on the workpiece

Explanation

Parallax error occurs when the eye is not directly over the graduation being read, so the apparent position of the mark shifts against the scale. Keeping the rule flat on the work and viewing straight down at eye level minimizes this error. Wiping the rule on the workpiece or tilting it changes the reference plane and adds uncertainty.

Question 42Hand tools, measuring instruments, and precision measurement

On a standard metric steel rule, the smallest graduation on the main scale is normally:

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

Explanation

A common metric steel rule is graduated in millimetres, with the smallest division usually 1 mm and longer marks at 5 mm and 10 mm. Values such as 0.5 mm appear on some rules but are not the standard smallest division. Readings finer than 1 mm require a vernier or micrometer.

Question 43Hand tools, measuring instruments, and precision measurement

An outside micrometer is checked with its spindle and anvil closed on the zero setting. The thimble zero is two divisions past the sleeve datum line. What does this indicate?

  1. The ratchet stop is worn and the reading is unaffected
  2. The micrometer reads 0.02 mm too small and must be adjusted
  3. The micrometer has a zero error and should be reset before use Correct answer.
  4. The anvil faces are parallel and the tool is within tolerance

Explanation

When the measuring faces are closed and the thimble zero does not align with the sleeve datum, the instrument carries a zero error. The error must be corrected with the adjusting spanner or noted and applied to every reading. Using the tool as-is would shift all measurements by the same offset.

Question 44Hand tools, measuring instruments, and precision measurement

A vernier caliper has a main scale with 1 mm divisions and a vernier scale of 50 divisions spanning 49 mm. What is the least count?

  1. 0.05 mm
  2. 0.02 mm Correct answer.
  3. 0.1 mm
  4. 0.01 mm

Explanation

Least count equals the main scale division minus the vernier division value: 1 mm − (49/50) mm = 0.02 mm. A 50-division vernier over 49 mm therefore resolves to 0.02 mm. This is the standard resolution of a typical 0.02 mm vernier caliper.

Question 45Hand tools, measuring instruments, and precision measurement

When taking a reading on a vernier caliper, which vernier graduation is used to obtain the fractional part?

  1. The graduation nearest the zero of the main scale
  2. The graduation that coincides exactly with a main scale mark Correct answer.
  3. The last graduation on the vernier scale
  4. The first graduation after the zero on the vernier scale

Explanation

The fractional reading is taken from the vernier graduation that lies exactly in line with a main scale graduation. That line number, multiplied by the least count, gives the fraction to add to the main scale reading. Choosing an approximate line introduces avoidable reading error.

Question 46Hand tools, measuring instruments, and precision measurement

A depth micrometer is used to check a blind bore. Which practice protects the accuracy of the measurement?

  1. Measure with the ratchet stop until three clicks are heard
  2. Measure at several points and record the deepest consistent reading Correct answer.
  3. Take the reading with the measuring rod extended beyond the sleeve
  4. Rock the micrometer slightly to feel for the bottom of the bore

Explanation

A blind bore may have a rough or curved bottom, so a single point can misrepresent the true depth. Taking several readings and using the consistent deepest value reduces the effect of local irregularities. The measuring rod should be perpendicular to the reference face throughout.

Question 47Hand tools, measuring instruments, and precision measurement

A dial test indicator is set up to check the runout of a shaft. The plunger should contact the work surface:

  1. at a steep angle to increase sensitivity
  2. perpendicular to the surface being checked Correct answer.
  3. at 45 degrees to the surface for clearance
  4. parallel to the shaft axis

Explanation

A dial test indicator gives true displacement only when the plunger is perpendicular to the measured surface. Angled contact introduces a cosine error that understates the actual movement. The stylus should also be positioned so it does not run off the edge of the work.

Question 48Hand tools, measuring instruments, and precision measurement

A 0–25 mm outside micrometer has a sleeve reading of 12.5 mm and a thimble reading of 28 divisions. If the thimble has 50 divisions, what is the total reading?

  1. 12.56 mm
  2. 12.50 mm
  3. 12.78 mm Correct answer.
  4. 13.06 mm

Explanation

Each thimble division represents 0.01 mm on a 0.5 mm pitch micrometer with 50 divisions. Multiplying 28 divisions by 0.01 mm gives 0.28 mm, which is added to the sleeve reading of 12.5 mm for 12.78 mm. The half-millimetre mark on the sleeve must be counted before adding the thimble fraction.

Question 49Hand tools, measuring instruments, and precision measurement

A try square is used to check a machined corner. Which condition shows the square is being used correctly?

  1. The work is tilted so the blade rests on the high corner
  2. The stock is pressed firmly against the reference face and the blade is viewed against a light source Correct answer.
  3. The square is held only by the blade while checking the corner
  4. The blade is tapped with a hammer to seat it on the work

Explanation

A try square must have its stock held flat and firm against the reference surface so the blade stands square to it. Viewing the blade against a light source reveals any gap that indicates out-of-square. Holding only the blade or tapping the tool distorts the check.

Question 50Hand tools, measuring instruments, and precision measurement

A machinist needs to transfer a measurement from a caliper to a workpiece with a scriber. Which tool is designed for this layout task?

  1. Spring divider Correct answer.
  2. Outside caliper
  3. Hermaphrodite caliper
  4. Vernier height gauge

Explanation

A spring divider has two sharp points and is used to scribe arcs and step off equal distances on layout work. An outside caliper has curved legs for transferring outside sizes, not for scribing. A height gauge is used on a surface plate rather than for hand layout on a workpiece.