ASME GDTP Geometric Dimensioning and Tolerancing Professional Exam — Questions and Answers

Question 1: Under ASME Y14.5, which of the following tolerances CAN be legally modified with LMC?

True Position of a hole (Correct answer)
Flatness
Circularity (Roundness)
Parallelism of a surface

Correct answer: True Position of a hole

True position references a feature of size (the hole), so LMC is applicable; surface-only controls like flatness, circularity, and surface parallelism cannot use material condition modifiers.

Question 2: What does the profile of a line control in GD&T?

The contour of a feature. (Correct answer)
The center of a circle.
The length of a side.
The angle of a feature.

Correct answer: The contour of a feature.

Profile of a line in GD&T is a 2D tolerance that controls the contour of a feature along a specific cross-section. It defines a tolerance zone that extends along the length of the feature, ensuring that all points on that line segment lie within the specified boundaries. This is used for features where the cross-sectional shape is critical, but the entire surface profile might not be.

Question 3: What does the symbol 'Ø' placed before a tolerance value in a feature control frame indicate?

The feature is a hole
The feature requires a circularity check
The tolerance applies to diameter measurement
The tolerance zone is cylindrical (Correct answer)

Correct answer: The tolerance zone is cylindrical

The diameter symbol (Ø) before a tolerance value specifies a cylindrical (3D) tolerance zone rather than two parallel planes.

Question 4: When total runout is applied to a cylindrical surface relative to a datum axis, it controls the cumulative effect of which geometric variations?

Straightness and Flatness only.
Circularity and Profile of a Line only.
Coaxiality and Perpendicularity only.
Circularity, straightness, coaxiality, and taper. (Correct answer)

Correct answer: Circularity, straightness, coaxiality, and taper.

Total runout provides a comprehensive 3D control over the entire surface. For a cylinder, this means it controls how round each section is (circularity), how straight the elements are along its length (straightness), how well its axis is aligned with the datum axis (coaxiality), and any uniform change in diameter along the length (taper).

Question 5: In the context of profile tolerancing, what does 'between' notation (using the symbol ↔ or the word BETWEEN) indicate?

The tolerance applies between two datum planes
The tolerance is split equally between two surfaces
The profile tolerance applies only to the portion of the surface between two specified points or features (Correct answer)
The profile tolerance uses bilateral distribution

Correct answer: The profile tolerance applies only to the portion of the surface between two specified points or features

The 'between' notation limits the profile tolerance application to a specific portion of the surface, bounded by two designated points or features.

Question 6: A datum feature simulator for a flat primary datum must be:

Perfectly parallel to the secondary datum
Nominally perfect in form (Correct answer)
Adjustable to fit the part surface
Oriented to the tertiary datum first

Correct answer: Nominally perfect in form

Datum feature simulators are nominally perfect counterparts of the datum feature, used to establish the datum from which measurements are taken.

Question 7: If a shaft is bent (curved axis), which runout measurement will show the largest FIM reading?

Circular runout at either end
Total runout along the full length (Correct answer)
Both circular and total will show identical readings
Circular runout at the midpoint

Correct answer: Total runout along the full length

Total runout captures all cumulative surface deviations including the effect of a bent axis along the entire length, giving the largest FIM reading.

Question 8: What does the outer boundary (OB) represent for a pin?

The resultant condition at LMC
The largest space the pin can occupy, equal to MMC plus the geometric tolerance (Correct answer)
The nominal pin diameter
The smallest diameter the pin can be

Correct answer: The largest space the pin can occupy, equal to MMC plus the geometric tolerance

Outer boundary for a pin = MMC + geometric tolerance, the largest envelope any conforming pin can produce.

Question 9: Under ASME Y14.5, what is the default geometric tolerance condition when no modifier is shown?

Least Material Condition (LMC)
Regardless of Feature Size (RFS) (Correct answer)
Maximum Material Condition (MMC)
Free State

Correct answer: Regardless of Feature Size (RFS)

Per Rule #2, RFS is the default — the geometric tolerance zone is fixed at the stated value regardless of the feature's actual produced size.

Question 10: On an internal feature (hole), the LMC condition corresponds to which of the following?

Smallest allowable hole diameter (Correct answer)
Virtual condition boundary
Midpoint of the tolerance range
Largest allowable hole diameter

Correct answer: Smallest allowable hole diameter

For a hole (internal feature), LMC is the smallest diameter because that represents the least material removed.

Question 11: A part drawing shows a runout callout with two datum references (e.g., A-B). What does this typically indicate?

The datum axis is established by two datum features used together (Correct answer)
Only datum A is used; datum B is a backup
The runout is measured alternately from datum A then datum B
The tolerance applies to both surfaces simultaneously

Correct answer: The datum axis is established by two datum features used together

Two datum references for runout typically establish a common datum axis from two separate datum features used simultaneously.

Question 12: Which of the following GD&T tolerances is most commonly applied with an MMC modifier to take advantage of bonus tolerance for assembly purposes?

Circularity
Profile of a Surface
Flatness
True Position (Correct answer)

Correct answer: True Position

True position is most commonly modified with MMC because assembly clearance naturally increases when mating features depart from MMC.

Question 13: A shaft has a true position tolerance of 0.2 MMC. At MMC the shaft diameter is 20.0 mm. If the shaft is produced at 19.8 mm, what is the total allowable position tolerance?

0.8 mm
0.2 mm
0.6 mm
0.4 mm (Correct answer)

Correct answer: 0.4 mm

The shaft has departed 0.2 mm from MMC, so the bonus tolerance (0.2) is added to the stated tolerance (0.2), giving 0.4 mm total.

Question 14: An engineer wants to ensure a minimum edge distance is maintained as a hole's position shifts. Which modifier applied to the position tolerance would best protect edge distance?

Free State — measures the part unconstrained
RFS — keeps the tolerance constant regardless of size
MMC — maximizes bonus when the hole is largest
LMC — provides tighter positional control when the hole is at its largest (least material) (Correct answer)

Correct answer: LMC — provides tighter positional control when the hole is at its largest (least material)

LMC tightens position control as the hole grows larger (less edge material), protecting minimum edge distance at the worst-case scenario.

Question 15: What does the datum symbol ⊥ represent in GD&T?

Symmetry to a reference.
Maximum allowable dimension.
Perpendicularity to a datum surface. (Correct answer)
Datum axis.

Correct answer: Perpendicularity to a datum surface.

The symbol ⊥ in GD&T represents perpendicularity. When applied to a feature, it specifies that the feature's surface, axis, or center plane must be oriented at a 90-degree angle relative to a specified datum or datum reference frame within a given tolerance zone. This ensures precise angular alignment between features.

Question 16: Which datum modifier requires the datum feature simulator to expand or contract to make maximum contact with the datum feature?

MMC (Maximum Material Condition)
LMC (Least Material Condition)
BSC (Basic)
RFS (Regardless of Feature Size) (Correct answer)

Correct answer: RFS (Regardless of Feature Size)

Under RFS (regardless of feature size), the datum feature simulator adjusts to make maximum contact with the actual datum feature surface, with no datum shift allowed.

Question 17: What is a 'feature of size' as defined by ASME Y14.5?

A feature with directly opposed elements — such as a cylinder, hole, or two parallel surfaces — definable by a single size dimension (Correct answer)
A surface that has a datum callout
Any feature drawn on an engineering print
A feature controlled exclusively by profile tolerance

Correct answer: A feature with directly opposed elements — such as a cylinder, hole, or two parallel surfaces — definable by a single size dimension

A feature of size has directly opposed surfaces or elements that can be measured across a single dimension, enabling MMC and LMC modifiers to apply.

Question 18: What is a 'basic dimension' in relation to a datum reference frame?

A dimension measured from a datum
A theoretically exact dimension used to locate a datum or feature (Correct answer)
A dimension with a tolerance of ±0.001
A dimension that requires no tolerance

Correct answer: A theoretically exact dimension used to locate a datum or feature

Basic dimensions are theoretically exact values enclosed in a box, used to define the true position of features relative to a datum reference frame.

Question 19: Which of the following is NOT a valid runout tolerance symbol in ASME Y14.5?

Total Runout
Total Runout of a Plane Surface (Correct answer)
Circular Runout
Runout of a Conical Surface

Correct answer: Total Runout of a Plane Surface

There is no separate GD&T symbol called 'Total Runout of a Plane Surface'; Total Runout (the arrow symbol) covers cylindrical and planar surfaces within one symbol.

Question 20: A pin has an MMC of 10.2 mm and a perpendicularity tolerance of 0.1 mm at MMC. What is its virtual condition?

10.3 mm (Correct answer)
10.0 mm
10.2 mm
10.1 mm

Correct answer: 10.3 mm

Virtual condition for an external feature = MMC + geometric tolerance = 10.2 + 0.1 = 10.3 mm.

Question 21: On a drawing, runout is specified with datum reference A, which is a short cylindrical feature. What concern might an inspector raise?

Short datums require a higher tolerance value
Runout cannot use cylindrical datums
Short datum features can be less stable for establishing an accurate axis (Correct answer)
The inspector must use CMM for short datum features

Correct answer: Short datum features can be less stable for establishing an accurate axis

Short datum features provide limited constraint for establishing a stable axis, which can introduce uncertainty in the runout measurement.

Question 22: The diameter symbol (ø) placed before a tolerance value in a feature control frame means the tolerance zone is:

Spherical
A width between two parallel lines
Equal in all directions on a flat plane
Cylindrical (Correct answer)

Correct answer: Cylindrical

When ø precedes the tolerance value, the tolerance zone is a cylinder of that diameter surrounding the true axis or center.

Question 23: What is the primary difference between a bilateral and unilateral profile tolerance zone?

Bilateral applies to surfaces; unilateral applies to lines only
Bilateral uses tighter tolerances than unilateral
Bilateral requires a datum; unilateral does not
Bilateral distributes the tolerance equally on both sides; unilateral places it entirely on one side of the true profile (Correct answer)

Correct answer: Bilateral distributes the tolerance equally on both sides; unilateral places it entirely on one side of the true profile

A bilateral profile tolerance distributes the zone equally on both sides of the true profile, while a unilateral tolerance places the entire zone on one side.

Question 24: In GD&T, what is the term for the actual part surface used to establish a datum?

Datum reference
Datum plane
Datum target
Datum feature (Correct answer)

Correct answer: Datum feature

A datum feature is the actual feature on the part (surface, axis, or center plane) that contacts the datum feature simulator to establish the datum.

Question 25: A primary datum feature that is an external cylinder contacts its simulator at:

The maximum inscribed cylinder (inner surface)
The full length of the cylindrical surface
The minimum circumscribed cylinder (outer surface) (Correct answer)
Three equally spaced points on one end

Correct answer: The minimum circumscribed cylinder (outer surface)

An external cylindrical datum feature is simulated by the minimum circumscribed cylinder that perfectly contacts the high points of the external surface.

Question 26: Two single-segment position callouts differ from a composite callout because:

Each segment of a two single-segment callout independently locates features from its referenced datums (Correct answer)
Two single-segment callouts apply only to patterns of two features
Two single-segment callouts cannot reference the same datums
Two single-segment callouts always have larger tolerances

Correct answer: Each segment of a two single-segment callout independently locates features from its referenced datums

In a two single-segment callout, each segment independently locates features from its own datum references, whereas the FRTZF in a composite callout controls only feature-to-feature relationships.

Question 27: Which datum feature simulator contact rule applies when establishing a primary datum plane from a flat surface?

Minimum circumscribed contact
Minimum contact with 1 point
Maximum inscribed contact
True contact with at least 3 points (Correct answer)

Correct answer: True contact with at least 3 points

A primary datum plane is established by physical contact with at least 3 high points on the part surface.

Question 28: When a feature control frame is attached to an extension line or dimension line (not a leader to the surface), what does this indicate?

The tolerance is informational only
The tolerance applies directly to the surface
The tolerance applies to the derived axis or center plane of the feature (Correct answer)
The tolerance applies to the entire part

Correct answer: The tolerance applies to the derived axis or center plane of the feature

Attaching a feature control frame to a dimension line means the tolerance controls the derived axis or center plane, not the physical surface itself.

Question 29: Which scenario correctly describes when composite tolerancing provides an advantage over a single position callout?

When the part has no orientation requirements
When the pattern location relative to datums can be loose, but feature-to-feature spacing must be tight (Correct answer)
When all features must be at the same absolute location
When only one feature is being controlled

Correct answer: When the pattern location relative to datums can be loose, but feature-to-feature spacing must be tight

Composite tolerancing is advantageous when the overall pattern location can have a larger tolerance while the individual feature spacing within the pattern must be held to a tighter tolerance.

Question 30: Under ASME Y14.5-2009, when no material condition modifier is specified for a feature of size, which modifier is implied?

MMC
RFS (Correct answer)
Free State
LMC

Correct answer: RFS

ASME Y14.5-2009 established RFS as the default when no modifier symbol is shown in the feature control frame.

Question 31: A drafter specifies two separate, coplanar surfaces on a part as a single primary datum feature. Which of the following geometric tolerances is best suited to control the relationship between these two surfaces?

Flatness
Parallelism
Position
Profile of a Surface (Correct answer)

Correct answer: Profile of a Surface

Profile of a Surface is the most appropriate control for two coplanar surfaces designated as a single datum. It establishes a tolerance zone of two parallel planes within which both surfaces must lie, thereby controlling their form and coplanarity relative to each other.

Question 32: Which standard governs GD&T practices in the United States?

ISO 1101
MIL-STD-8C
ASME Y14.5 (Correct answer)
ANSI B4.1

Correct answer: ASME Y14.5

ASME Y14.5, published by the American Society of Mechanical Engineers, is the U.S. standard defining GD&T symbols, rules, and practices.

Question 33: A datum reference frame uses two coaxial cylinders called out as a compound datum [A-B]. What is the effect of this designation?

Datum A and B are measured independently and averaged
Both cylinders together establish a single datum axis with higher accuracy than either alone (Correct answer)
The compound datum eliminates the need for a primary planar datum
Datum A is primary and datum B is secondary with no connection

Correct answer: Both cylinders together establish a single datum axis with higher accuracy than either alone

A compound datum [A-B] treats two coaxial datum features as a single combined axis, improving stability and accuracy of the datum axis compared to using either feature individually.

Question 34: What instrument is most commonly used to measure runout in a production environment?

Coordinate Measuring Machine (CMM) only
Dial test indicator (DTI) with the part rotating on centers or in a chuck (Correct answer)
Thread plug gauge
Optical comparator

Correct answer: Dial test indicator (DTI) with the part rotating on centers or in a chuck

A dial test indicator placed against the surface while the part rotates on centers or in a V-block is the standard production method for measuring runout.

Question 35: A feature control frame for a surface specifies an angularity tolerance. What is the shape of the tolerance zone?

A cylindrical zone around a theoretical axis
The space between two concentric circles on the surface
A conical zone originating from a datum vertex
Two parallel planes oriented at a basic angle to a datum (Correct answer)

Correct answer: Two parallel planes oriented at a basic angle to a datum

The tolerance zone for an angularity control applied to a surface is defined by two parallel planes. These planes are separated by the specified tolerance value and are oriented at the specified basic angle relative to the datum reference frame. All points of the controlled surface must lie within this zone.

Question 36: Under ASME Y14.5, the circularity (roundness) tolerance value must be:

Equal to the cylindricity tolerance
Greater than the size tolerance
Independent of the size tolerance
Less than or equal to the size tolerance (Correct answer)

Correct answer: Less than or equal to the size tolerance

Per Rule #1 (Envelope Principle), the circularity tolerance cannot exceed the size tolerance because the feature must remain within its size limits.

Question 37: A bolt pattern uses composite position with PLTZF ⌀1.0|A|B|C and FRTZF ⌀0.4|A. What does datum A control in the FRTZF?

Perpendicularity (orientation) of each hole to datum A (Correct answer)
The true position of the entire pattern
Location along the A datum plane
The size of the tolerance zone

Correct answer: Perpendicularity (orientation) of each hole to datum A

In the FRTZF, datum A (a flat surface) controls only the orientation (perpendicularity) of each hole relative to datum A, not the hole pattern's location.

Question 38: For a pin (external feature) at LMC with a position tolerance, resultant condition equals:

MMC plus the geometric tolerance
MMC minus the geometric tolerance
LMC plus the geometric tolerance
LMC minus the geometric tolerance (Correct answer)

Correct answer: LMC minus the geometric tolerance

For a pin, resultant condition = LMC − geometric tolerance, representing the smallest envelope the pin can produce.

Question 39: A movable datum target is identified on a drawing by:

A datum target symbol with a bold border
A datum target symbol enclosed in a rectangle
A datum target symbol with a triangle below it
Two parallel horizontal lines below the datum target symbol (Correct answer)

Correct answer: Two parallel horizontal lines below the datum target symbol

A movable datum target is indicated by two parallel horizontal lines (a slide symbol) beneath the standard datum target symbol to indicate it can be repositioned.

Question 40: What is the primary function of a datum in GD&T?

To ensure all features are identical.
To define the measurement reference for all other features. (Correct answer)
To adjust the shape of a part.
To control the size of a feature.

Correct answer: To define the measurement reference for all other features.

A datum in GD&T is a theoretically exact point, axis, or plane derived from a specified datum feature. Its primary function is to serve as a fundamental reference for measuring and controlling the location, orientation, and form of other features on a part. This ensures consistency in manufacturing and inspection processes.

Question 41: A drawing notes circular runout of 0.04 on a surface WITHOUT a diameter symbol (⌀). What does this imply?

The tolerance applies to individual cross-sections measured perpendicular to the datum axis (Correct answer)
The tolerance applies to the end face of the feature
The tolerance is invalid without a diameter symbol
The tolerance applies to the entire cylindrical surface as total runout

Correct answer: The tolerance applies to individual cross-sections measured perpendicular to the datum axis

Circular runout without a diameter symbol applies at individual cross-sections perpendicular to the datum axis, which is the standard interpretation of circular runout.

Question 42: In a composite feature control frame, the upper segment is called the:

Feature-Relating Tolerance (FRT)
Feature Level Control (FLC)
Feature Control Tolerance Zone (FCTZ)
Pattern-Locating Tolerance Zone Framework (PLTZF) (Correct answer)

Correct answer: Pattern-Locating Tolerance Zone Framework (PLTZF)

The upper segment of a composite feature control frame is called the Pattern-Locating Tolerance Zone Framework (PLTZF), which controls the location of the pattern as a whole.

Question 43: When applying composite position to a non-circular pattern (e.g., rectangular slots), the FRTZF tolerance zones are:

Converted to a bilateral profile tolerance
Always cylindrical regardless of feature shape
Applied only to the center plane of each slot
Shaped to match the tolerance zone type appropriate for the feature (e.g., width zones for slots) (Correct answer)

Correct answer: Shaped to match the tolerance zone type appropriate for the feature (e.g., width zones for slots)

For slot patterns, the FRTZF tolerance zones are parallel-plane (width) zones that match the center-plane geometry of the slots, not cylindrical zones.

Question 44: Which of the following characteristics makes concentricity difficult to verify?

It requires specialized runout equipment not commonly found in shops
It requires the part to be rotating during inspection
It requires deriving median points from opposing surface elements rather than direct surface measurement (Correct answer)
It cannot be measured on a surface plate

Correct answer: It requires deriving median points from opposing surface elements rather than direct surface measurement

Finding median points of diametrically opposed elements requires complex calculations, making concentricity verification more difficult than runout.

Question 45: For an internal feature (hole) at MMC with a position tolerance, virtual condition equals:

MMC plus the geometric tolerance
LMC minus the geometric tolerance
LMC plus the geometric tolerance
MMC minus the geometric tolerance (Correct answer)

Correct answer: MMC minus the geometric tolerance

For a hole, virtual condition = MMC − geometric tolerance, representing the smallest the hole boundary can be.

Question 46: Which datum reference is required for a runout tolerance callout?

No datum is required for runout
A datum point
A datum axis (Correct answer)
A datum plane only

Correct answer: A datum axis

Runout tolerances always require a datum axis because the surface elements are measured relative to rotation about that axis.

Question 47: For a clearance-fit assembly, which comparison guarantees that all conforming parts will assemble?

The pin's nominal size must equal the hole's nominal size
The pin's virtual condition must be less than or equal to the hole's virtual condition (Correct answer)
The pin's resultant condition must exceed the hole's inner boundary
The pin's LMC must be less than the hole's MMC

Correct answer: The pin's virtual condition must be less than or equal to the hole's virtual condition

Parts always assemble when the pin's virtual condition (worst-case largest) is no bigger than the hole's virtual condition (worst-case smallest).

Question 48: For a composite position callout, which statement about the FRTZF zone orientation is correct when datum A (a flat surface) is the only FRTZF datum?

The FRTZF zones are free to translate in X and Y but are locked in rotation about all axes
The FRTZF zones must remain perpendicular to datum A but may translate in X and Y (Correct answer)
The FRTZF zones are free to translate in all directions and rotate about all axes
The FRTZF zones are locked to the true position relative to datum A

Correct answer: The FRTZF zones must remain perpendicular to datum A but may translate in X and Y

With only datum A (primary flat surface) in the FRTZF, the zones must remain perpendicular to A (orientation locked) but can translate freely in X and Y within the PLTZF boundaries.

Question 49: A design engineer specifies runout instead of cylindricity on a bearing journal. What is a key advantage of this decision?

Runout is always a tighter control than cylindricity
Runout relates the surface to a datum axis relevant to function, while cylindricity does not reference a datum (Correct answer)
Runout allows MMC modifiers that cylindricity does not
Cylindricity cannot be measured in production environments

Correct answer: Runout relates the surface to a datum axis relevant to function, while cylindricity does not reference a datum

Runout ties surface quality to the functional datum axis (how the part actually rotates), while cylindricity only controls the surface form without a datum reference.

Question 50: A 'unilateral profile' tolerance where the band is entirely inside the true profile is indicated by:

An arrow pointing inward on the feature
Two separate tolerance values with a slash
A 'U' symbol with the inward offset value specified (Correct answer)
A minus sign before the tolerance

Correct answer: A 'U' symbol with the inward offset value specified

In ASME Y14.5-2009 and later, an unequal/unilateral profile tolerance is shown with the 'U' symbol and a value indicating how much of the tolerance is on one side.

Question 51: The simultaneous requirement applies to composite position tolerances when:

A cylindrical tolerance zone is specified
The same datum reference frame is shared and no SEP notation is used (Correct answer)
The FRTZF references more datums than the PLTZF
MMC modifier is applied to the PLTZF

Correct answer: The same datum reference frame is shared and no SEP notation is used

The simultaneous requirement applies when multiple position callouts reference the same datum reference frame without the SEP (Separately) notation, meaning they must be verified in the same setup.

Question 52: What is the relationship between virtual condition and bonus tolerance?

Both virtual condition and bonus tolerance change as the actual feature size changes
Virtual condition is a fixed boundary while bonus tolerance increases as the feature departs from MMC (Correct answer)
They represent the same value calculated from different starting points
Virtual condition increases at the same rate bonus tolerance decreases

Correct answer: Virtual condition is a fixed boundary while bonus tolerance increases as the feature departs from MMC

Virtual condition is constant (MMC ± geometric tolerance), whereas bonus tolerance is a variable that grows as the feature departs from MMC toward LMC.

Question 53: In GD&T, the 'Tangent Plane' modifier (circled T) means:

The feature must be tangent to a datum
The tolerance is applied in a tangential direction only
The tolerance applies to a plane tangent to the high points of the surface (Correct answer)
The tolerance applies to a tangential cross-section

Correct answer: The tolerance applies to a plane tangent to the high points of the surface

The tangent plane modifier specifies that the tolerance zone is evaluated using a plane contacting the high points of the surface rather than the entire surface.

Question 54: Virtual condition applies specifically when which modifier is called out in the feature control frame?

LMC (Least Material Condition)
RFS (Regardless of Feature Size)
MMC (Maximum Material Condition) (Correct answer)
Free State

Correct answer: MMC (Maximum Material Condition)

Virtual condition is tied to the MMC modifier; it defines the fixed worst-case boundary against which functional gauges and mating parts are designed.

Question 55: A cylindricity tolerance of 0.03 mm means the entire cylindrical surface must fit between two coaxial cylinders whose radii differ by:

0.06 mm
0.015 mm
0.03 mm (Correct answer)
0.03 mm per side (0.06 total)

Correct answer: 0.03 mm

The cylindricity tolerance value of 0.03 mm equals the total radial difference between the two coaxial boundary cylinders.

Question 56: What is a 'datum reference frame' (DRF) as defined in GD&T?

The set of all datum features on a drawing
A computer model used to simulate part assembly
Three mutually perpendicular planes that define the origin for dimensional measurements (Correct answer)
The physical fixture used to hold the part during inspection

Correct answer: Three mutually perpendicular planes that define the origin for dimensional measurements

A datum reference frame consists of three mutually perpendicular planes forming a 3D coordinate system from which the location and orientation of features are measured.

Question 57: A 'basic dimension' in GD&T is identified on a drawing by:

Underlining the dimension value
Adding the letters 'BSC' next to the value
Placing it in parentheses
Enclosing the value in a rectangular box (Correct answer)

Correct answer: Enclosing the value in a rectangular box

Basic dimensions are shown enclosed in a rectangular box and represent the exact theoretically perfect value from which toleranced dimensions are measured.

Question 58: Which of the following best describes the tolerance zone for total runout on a cylindrical surface?

A single cylinder centered on the actual axis
A series of concentric circles at each cross-section
Two parallel planes perpendicular to the datum axis
Two coaxial cylinders with a radial distance equal to the tolerance value (Correct answer)

Correct answer: Two coaxial cylinders with a radial distance equal to the tolerance value

The total runout tolerance zone for a cylinder is defined by two coaxial cylinders, one inside the other, separated by the stated tolerance value.

Question 59: The 'projected tolerance zone' symbol (P in a circle) is most commonly applied to:

Profile tolerances on curved surfaces
Threaded holes or press-fit pins to control mating part interference (Correct answer)
Flat surfaces requiring parallelism
Runout measurements on rotating shafts

Correct answer: Threaded holes or press-fit pins to control mating part interference

Projected tolerance zones extend the position tolerance above a hole to the height of the mating pin or fastener, preventing interference during assembly.

Question 60: What does the inner boundary (IB) represent for a hole?

The virtual condition at LMC
The nominal bore diameter
The largest condition of the hole at LMC
The smallest condition of the hole, equal to MMC minus the geometric tolerance (Correct answer)

Correct answer: The smallest condition of the hole, equal to MMC minus the geometric tolerance

Inner boundary for a hole = MMC − geometric tolerance, the tightest restriction that must still clear a mating pin.

Question 61: What is the purpose of the assembly requirements symbol in GD&T?

To facilitate easy assembly. (Correct answer)
To control the surface finish.
To control the shape of the part.
To ensure parts fit into the assembly.

Correct answer: To facilitate easy assembly.

The assembly requirements symbol, often depicted as a circle with a cross (⌖) or other specific notation, is used in GD&T to indicate that a feature or part is designed with specific tolerances to ensure it can be easily assembled with its mating components. This helps prevent binding, excessive force, or misalignment during the assembly process, improving manufacturing efficiency.

Question 62: A datum target point is represented on a drawing by:

A circle divided horizontally with an X (Correct answer)
A dashed circle with a cross
A solid filled triangle
A square with a center dot

Correct answer: A circle divided horizontally with an X

A datum target point is shown as a circle divided by a horizontal line, with an X in the lower half and the datum target identification in the upper half.

Question 63: In composite profile of a surface, what does the lower segment control compared to the upper segment?

Profile size tolerance only
The material condition of the surface
Surface finish requirements
Profile form, orientation, and feature-to-feature location (but not absolute location) (Correct answer)

Correct answer: Profile form, orientation, and feature-to-feature location (but not absolute location)

The lower segment of composite profile controls form, orientation, and the relationship between features, but the tolerance zone can translate/rotate relative to the datum reference frame.

Question 64: When a face and diameter are used together as compound datums for runout, what geometric relationship do they establish?

Two parallel planes
A datum center point only
A floating axis with no angular constraint
A datum axis perpendicular to a datum plane at a specific point (Correct answer)

Correct answer: A datum axis perpendicular to a datum plane at a specific point

A compound datum combining a face and diameter establishes a datum axis that is perpendicular to the face and coincident with the diameter's axis.

Question 65: What is the key difference between the application of a flatness tolerance and a parallelism tolerance to a planar surface?

Parallelism requires a datum reference, while flatness does not. (Correct answer)
The tolerance zone for flatness is cylindrical, while for parallelism it is planar.
Flatness can be modified by MMC, but parallelism cannot.
Flatness controls surface waviness, while parallelism controls roughness.

Correct answer: Parallelism requires a datum reference, while flatness does not.

The fundamental difference is that flatness is a form control and is independent of any other feature. Parallelism is an orientation control, which by definition must relate the orientation of one feature to another (a datum). Therefore, parallelism requires a datum reference in its feature control frame, whereas flatness does not.

Question 66: Which of the following is NOT a valid datum feature type in ASME Y14.5?

Theoretical perfect plane in free space (Correct answer)
Planar surface
Width feature of size
Cylindrical feature of size

Correct answer: Theoretical perfect plane in free space

Datums are established from real physical features on the part; a theoretical plane with no physical basis cannot serve as a datum feature.

Question 67: A perpendicularity callout with a diameter symbol (⌀) preceding the tolerance value on an axis means the tolerance zone is:

Two parallel planes parallel to the datum
A cylindrical zone perpendicular to the datum (Correct answer)
Two parallel planes perpendicular to the datum
A square zone of side equal to the tolerance value

Correct answer: A cylindrical zone perpendicular to the datum

The diameter symbol (⌀) before the perpendicularity tolerance value specifies a cylindrical tolerance zone rather than a two-plane zone.

Question 68: Which of the following is a valid reason to choose composite tolerancing over a tighter single position tolerance?

To allow more variation in pattern location relative to datums while ensuring parts assemble correctly with mating features (Correct answer)
To apply different geometric characteristics to the same feature
To eliminate the need for functional gauging
To avoid specifying datums on the drawing

Correct answer: To allow more variation in pattern location relative to datums while ensuring parts assemble correctly with mating features

Composite tolerancing allows a loose location tolerance for assembly into a housing while maintaining tight feature-to-feature spacing needed for mating with a bolt pattern, optimizing manufacturability.

Question 69: A composite positional tolerance controls a pattern of slots. The FRTZF is wider than the individual slot tolerance zone. This situation is:

Valid because the FRTZF overrides the size tolerance
Invalid because the FRTZF must always be smaller than the PLTZF (Correct answer)
Invalid because the FRTZF cannot exceed the pattern size tolerance
Valid if MMC modifier is used

Correct answer: Invalid because the FRTZF must always be smaller than the PLTZF

The FRTZF tolerance must always be equal to or smaller than the PLTZF tolerance, since the FRTZF zones must fit within the PLTZF framework.

Question 70: A feature control frame reads: position | 0.3Ⓜ | A | BⓂ. What does the Ⓜ on datum B indicate?

Datum shift is allowed based on datum B's departure from MMC (Correct answer)
The controlled feature is at MMC
Datum B must be inspected at MMC only
Bonus tolerance on the controlled feature

Correct answer: Datum shift is allowed based on datum B's departure from MMC

An MMC modifier on a datum reference (B Ⓜ) permits the datum reference frame to shift by the amount datum feature B departs from its MMC.

Question 71: What does the term 'allowance' refer to in tolerance and fit terminology?

The difference between upper and lower deviations
The nominal size of the feature
The total tolerance range of both parts
The minimum clearance or maximum interference between mating parts (Correct answer)

Correct answer: The minimum clearance or maximum interference between mating parts

Allowance is the intentional difference between mating parts — minimum clearance for clearance fits or maximum interference for interference fits.

Question 72: When a cylindrical feature is used as a secondary datum after a planar primary datum, how many additional degrees of freedom does it constrain?

4
3
2 (Correct answer)
1

Correct answer: 2

A secondary datum cylinder constrains 2 translational degrees of freedom (the two directions perpendicular to the cylinder's axis).

Question 73: Which symbol is used to define the origin of a datum in GD&T?

A circle symbol.
A triangle symbol.
A square symbol.
A rectangle symbol. (Correct answer)

Correct answer: A rectangle symbol.

The datum feature symbol in GD&T is a capital letter enclosed in a rectangle, connected to the feature by a leader line or directly to the feature's extension line. This symbol identifies a specific feature on a part as a datum, which serves as a primary reference for other geometric tolerances and defines the origin for measurements.

Question 74: What does the Free State modifier (encircled F) in a feature control frame specify?

No fixture is needed for any inspection of this part
The feature tolerance applies only at room temperature
The geometric tolerance applies to the part in its unrestrained, free (unclamped) condition (Correct answer)
The feature is a floating datum

Correct answer: The geometric tolerance applies to the part in its unrestrained, free (unclamped) condition

The free state modifier requires that the specified geometric tolerance be met without any restraining fixture, which is critical for non-rigid or flexible parts.

Question 75: In a composite feature control frame with two segments, what does the upper segment control?

The size tolerance of each feature
The orientation of individual features only
The feature-to-feature relationship within the pattern
The location of the entire pattern relative to the datum reference frame (Correct answer)

Correct answer: The location of the entire pattern relative to the datum reference frame

The upper segment of a composite callout controls where the pattern is located relative to the specified datums, while the lower segment refines the within-pattern accuracy.

Question 76: When a datum reference is repeated in both the PLTZF and FRTZF of a composite callout, what does it mean in the lower segment?

It restricts the FRTZF from translating relative to that datum (Correct answer)
It applies the tolerance to that datum feature only
It has no effect in the lower segment
It doubles the tolerance value

Correct answer: It restricts the FRTZF from translating relative to that datum

When a datum is repeated in the FRTZF, it restricts translation of the tolerance zone relative to that datum while still allowing the zone to shift in other directions.

Question 77: What major new symbol was introduced in the ASME Y14.5-2018 revision?

The Free State modifier
The Independent modifier (encircled I), which overrides Rule #1 for a specific feature (Correct answer)
The Tangent Plane modifier
The Projected Tolerance Zone symbol

Correct answer: The Independent modifier (encircled I), which overrides Rule #1 for a specific feature

ASME Y14.5-2018 introduced the Independent modifier (Ⓘ), which explicitly releases a feature from Rule #1's perfect-form-at-MMC requirement.

Question 78: Why is symmetry sometimes used as an alternative to concentricity for symmetric features?

Symmetry is easier to apply to non-round features than concentricity (Correct answer)
Symmetry is cheaper to inspect than concentricity
Symmetry only applies to prismatic features while concentricity applies to round ones
Symmetry allows MMC modifiers while concentricity does not

Correct answer: Symmetry is easier to apply to non-round features than concentricity

Symmetry controls the median points of features relative to a datum plane, making it applicable to non-cylindrical symmetric features where concentricity is not appropriate.

Question 79: A designer specifies composite position with PLTZF ⌀0.5 and FRTZF ⌀0.5. What is the practical effect?

The feature spacing is twice as tight as the pattern location
The two zones create a spherical tolerance zone
The FRTZF has no additional restraint beyond the PLTZF (Correct answer)
The PLTZF is redundant and can be eliminated

Correct answer: The FRTZF has no additional restraint beyond the PLTZF

When PLTZF and FRTZF have equal values, the lower segment provides no additional tightening of feature-to-feature relationships beyond what the upper segment already requires.

Question 80: A circular runout symbol (single arrow circle) is placed on a drawing. What is the standard symbol used?

A circle with a single diagonal arrow (Correct answer)
A circle with two arrows pointing outward
Two concentric circles
A half-circle with an arrow

Correct answer: A circle with a single diagonal arrow

The circular runout symbol in GD&T is a circle with a single diagonal arrow, distinguishing it from total runout which uses a double arrow.

Question 81: What does it mean when a straightness tolerance is applied to the derived median line of a shaft rather than its surface?

The surface elements must be straight
The shaft must be perfectly round
Rule #1 is overridden and the shaft axis may bow outside the MMC boundary (Correct answer)
The size tolerance is tightened

Correct answer: Rule #1 is overridden and the shaft axis may bow outside the MMC boundary

Straightness of the derived median line overrides Rule #1, allowing the axis to bend outside the perfect-form-at-MMC boundary while the shaft remains within size limits at each cross-section.

Question 82: Two mating parts use a clearance fit. The designer wants maximum allowable positional error when parts are easiest to assemble. Which modifier should be applied?

Free State
LMC
MMC (Correct answer)
RFS

Correct answer: MMC

MMC provides maximum bonus tolerance when parts are at their smallest shaft / largest hole (most clearance), maximizing allowed position error when assembly is easiest.

Question 83: What happens to the FRTZF tolerance zone framework if no orientation datums are referenced in it?

The FRTZF zones are free to rotate and translate relative to the DRF (Correct answer)
The FRTZF is invalid and must reference at least one datum
The FRTZF applies only at the true position of each feature
The FRTZF defaults to the same datums as the PLTZF

Correct answer: The FRTZF zones are free to rotate and translate relative to the DRF

If no datums are cited in the FRTZF, the tolerance zone framework is free to translate and rotate in any direction, only constrained to maintain the pattern geometry internally.

Question 84: How many tolerance zones exist for each feature in a composite position callout with both PLTZF and FRTZF?

Two separate zones — one from each segment (Correct answer)
Three zones — size, location, and orientation
One combined zone
Four zones — one per datum referenced

Correct answer: Two separate zones — one from each segment

Each feature must simultaneously satisfy two tolerance zones: the larger PLTZF zone (which locates the pattern) and the smaller FRTZF zone (which controls feature-to-feature relationships).

Question 85: In GD&T, what is the purpose of the datum feature symbol (a rectangle with a triangle)?

To identify a feature that serves as an origin for measurements (Correct answer)
To indicate a tolerance zone shape
To specify a material condition modifier
To denote a reference dimension

Correct answer: To identify a feature that serves as an origin for measurements

The datum feature symbol identifies physical features on a part that establish the coordinate system used for measurements and inspections.

Question 86: Which symbol designates a datum target area in GD&T?

An X inside a circle
A square frame around the dimension
A triangle pointing to the surface
A circle divided by a horizontal line with the target ID (Correct answer)

Correct answer: A circle divided by a horizontal line with the target ID

A datum target symbol is a circle divided by a horizontal line; the lower half contains the datum letter and target number (e.g., A1).

Question 87: The GD&T symbol for 'Angularity' controls which characteristic?

The form of an angled surface independently of datums
The runout of a feature at an angle
The orientation of a surface at a specified angle to a datum (Correct answer)
The location of a surface relative to a datum

Correct answer: The orientation of a surface at a specified angle to a datum

Angularity is an orientation control that constrains a surface or axis to a specified angle (other than 0° or 90°) relative to a datum.

Question 88: What does 'free fit' mean in engineering drawings?

There is no interference between parts. (Correct answer)
The parts are tightly constrained.
There is some clearance between parts.
The parts are permanently fixed.

Correct answer: There is no interference between parts.

A 'free fit' is a type of clearance fit characterized by a relatively large and consistent clearance between mating parts, ensuring easy assembly and free movement. This means that even at their worst-case material conditions, the parts will not interfere with each other. It's often used where precise location isn't critical but ease of assembly and movement are paramount.

Question 89: What does the datum target symbol ⌖ mean in GD&T?

The maximum allowable tolerance.
The surface finish requirement.
A defined point or area on a feature to align with a datum. (Correct answer)
The location of a feature.

Correct answer: A defined point or area on a feature to align with a datum.

The datum target symbol ⌖ is used to specify a specific point, line, or area on a feature that will be used to establish a datum. This is particularly useful for irregular or large surfaces where using the entire feature as a datum would be impractical or lead to instability. Datum targets ensure a precise and repeatable contact for measurement and fixturing.

Question 90: The 'Profile of a Line' symbol controls:

The shape of a cross-sectional slice of a surface at a single cutting plane (Correct answer)
The straightness of a line element
The orientation of a line to a datum
The 3D shape of an entire surface

Correct answer: The shape of a cross-sectional slice of a surface at a single cutting plane

Profile of a Line (single arc symbol) applies the profile tolerance to each individual 2D cross-section independently, not to the whole 3D surface.

Question 91: A part drawing shows composite position with PLTZF ⌀0.8|A|B|C and FRTZF ⌀0.3|A|B|C. This is functionally equivalent to:

A composite callout with no PLTZF datums
A single position callout of ⌀0.3|A|B|C
Two single-segment callouts of ⌀0.8|A|B|C and ⌀0.3|A|B|C (Correct answer)
A profile callout of 0.4|A|B|C

Correct answer: Two single-segment callouts of ⌀0.8|A|B|C and ⌀0.3|A|B|C

When all three datums appear in both segments of a composite frame, it is functionally equivalent to two single-segment position callouts because the FRTZF is fully constrained with no freedom to translate or rotate.

Question 92: What is the purpose of using multiple datum targets (e.g., A1, A2, A3) to establish a single datum plane?

To simulate a datum plane on a non-flat or flexible surface using discrete contact points (Correct answer)
To increase measurement speed
To allow datum shift in three axes simultaneously
To create redundant inspection checkpoints

Correct answer: To simulate a datum plane on a non-flat or flexible surface using discrete contact points

Multiple datum targets simulate a plane on irregular surfaces (like castings) by defining exact contact points rather than relying on full surface contact.

Question 93: In ASME Y14.5-2018, which symbol is used to indicate 'Separately' when the simultaneous requirement should NOT apply to composite callouts on the same drawing?

SQ
ISO
SEP (Correct answer)
SIM

Correct answer: SEP

The notation 'SEP REQT' (Separately) is added to indicate that multiple geometric tolerances referencing the same DRF should be verified independently rather than simultaneously.

Question 94: A datum reference frame is established by a minimum of:

Two datum features
One datum feature
Six datum features
Three datum features (Correct answer)

Correct answer: Three datum features

A complete datum reference frame typically requires three mutually perpendicular datum planes established from at least three datum features to fully constrain six degrees of freedom.

Question 95: Can a composite feature control frame be used with profile of a surface tolerances?

No, profile uses bilateral tolerances exclusively
No, composite frames are only valid for position tolerances
Yes, but only for internal features
Yes, composite profile tolerances are explicitly defined in ASME Y14.5 (Correct answer)

Correct answer: Yes, composite profile tolerances are explicitly defined in ASME Y14.5

ASME Y14.5 explicitly defines composite profile tolerances, where the upper segment controls location and the lower segment controls form, orientation, and feature-to-feature relationships.

Question 96: When datum targets are used to establish a primary datum plane, the minimum number of target points required is:

Two
One
Four
Three (Correct answer)

Correct answer: Three

A minimum of three datum target points are needed to define a primary datum plane, just as three points define a unique plane in space.

Question 97: Which symbol on a feature control frame indicates a 'simultaneous requirement' is not in effect and features are verified independently?

A double-headed arrow
Circled S modifier
SEP REQT (Separate Requirement) notation (Correct answer)
Two stacked feature control frames

Correct answer: SEP REQT (Separate Requirement) notation

Adding 'SEP REQT' (Separate Requirement) to a feature control frame means each callout is gauged independently rather than simultaneously.

Question 98: A composite callout has PLTZF|A|B|C and FRTZF|A|B. Compared to FRTZF|A only, what additional constraint does adding datum B impose?

Restricts rotation about the axis perpendicular to datum B
Removes all translational freedom from the FRTZF
Restricts translation perpendicular to datum B
Restricts rotation about the datum B axis (Correct answer)

Correct answer: Restricts rotation about the datum B axis

Adding datum B (typically a secondary datum) to the FRTZF restricts the rotational degree of freedom about the axis perpendicular to datum B, locking the pattern's clocking.

Question 99: How are datum features typically indicated in GD&T?

By a circle symbol.
By a diamond-shaped symbol.
By a rectangle symbol. (Correct answer)
By an arrow symbol.

Correct answer: By a rectangle symbol.

Datum features are typically indicated in GD&T by a capital letter enclosed within a rectangle, connected to the feature by a leader line or directly to the feature's extension line. This symbol clearly identifies which feature on the part is being designated as a datum, establishing it as a reference for other geometric tolerances.

Question 100: Which boundary concept and modifier are used to protect minimum wall thickness or edge distance?

Inner boundary with RFS
Outer boundary with the free-state modifier
Virtual condition with the MMC modifier
Resultant condition with the LMC modifier (Correct answer)

Correct answer: Resultant condition with the LMC modifier

The LMC modifier and resultant condition ensure enough material remains at the part's thinnest point, preventing breakout or structural failure.

Question 101: Which fit is typically used for bearings that must rotate freely with minimal play?

H7/f7 (running clearance fit) (Correct answer)
H7/n6 (transition fit)
H7/p6 (interference fit)
H7/h6 (sliding fit)

Correct answer: H7/f7 (running clearance fit)

H7/f7 provides a reliable running clearance suitable for bearings and rotating shafts that need free rotation with controlled play.

Question 102: Which of the following GD&T symbols controls both the form and the orientation of a surface with respect to a datum?

Circularity
Flatness
Straightness
Angularity (Correct answer)

Correct answer: Angularity

Angularity controls the orientation of a surface or axis at a specified angle to a datum, inherently also controlling form within the tolerance zone.

Question 103: A hole has MMC = 9.8 mm and a position tolerance of 0.2 mm at MMC. What is its virtual condition?

10.4 mm
9.8 mm
10.0 mm
9.6 mm (Correct answer)

Correct answer: 9.6 mm

Virtual condition for a hole = MMC − geometric tolerance = 9.8 − 0.2 = 9.6 mm.

Question 104: What is the functional significance of datum precedence order (primary, secondary, tertiary)?

It determines which degrees of freedom each datum constrains, in priority order, during measurement and assembly (Correct answer)
It dictates the order in which dimensions are inspected
It specifies which datum has the tightest positional tolerance
It is cosmetic and has no effect on inspection

Correct answer: It determines which degrees of freedom each datum constrains, in priority order, during measurement and assembly

Primary datum constrains three degrees of freedom, secondary constrains two more, and tertiary constrains the last one — order matters for repeatability of measurement.

Question 105: What effect does applying the LMC modifier (L) to a datum feature reference have?

The datum is established only from external features
The datum feature must be at its smallest allowable size for any measurement
The datum feature tolerance is reduced to zero
Datum shift is permitted as the datum feature departs from least material condition (Correct answer)

Correct answer: Datum shift is permitted as the datum feature departs from least material condition

When LMC is applied to a datum feature reference, bonus datum shift is permitted as the datum feature departs from its least material condition toward MMC.

Question 106: Cylindricity differs from circularity in that cylindricity controls:

Only cross-sectional roundness
Both the roundness and straightness of the entire surface simultaneously (Correct answer)
The diameter variation only
The axis orientation only

Correct answer: Both the roundness and straightness of the entire surface simultaneously

Cylindricity simultaneously controls circularity, straightness, and taper of the entire cylindrical surface in a single tolerance.

Question 107: The fundamental deviation in ISO limits and fits defines:

The position of the tolerance zone relative to nominal size (Correct answer)
The surface quality required
The total tolerance range
The inspection method to be used

Correct answer: The position of the tolerance zone relative to nominal size

The fundamental deviation (indicated by a letter) sets where the tolerance zone starts — how far it is offset from the nominal size.

Question 108: A functional (go) gauge designed to check a pin is sized to which boundary?

Virtual condition (Correct answer)
Nominal drawing size
LMC size
Resultant condition

Correct answer: Virtual condition

A go gauge is sized to the virtual condition so it accepts every conforming pin while rejecting those that violate the worst-case boundary.

Question 109: In a datum reference frame, the tertiary datum plane is established by a minimum of how many points of contact?

Four
One (Correct answer)
Three
Two

Correct answer: One

The tertiary datum plane requires a minimum of one point of contact because it only needs to constrain one remaining translational degree of freedom.

Question 110: What does the term 'clearance fit' refer to in GD&T?

A tight fit that requires force to assemble.
A fit that allows for movement between parts. (Correct answer)
A fit with no movement between parts.
A fit used only for fastening components.

Correct answer: A fit that allows for movement between parts.

A 'clearance fit' in GD&T refers to a condition where there is always a gap or space between mating parts when they are assembled, even at their worst-case material conditions. This type of fit is designed to allow for free movement, rotation, or sliding between components. It is suitable for applications where parts need to move relative to each other without binding.

Question 111: What does the 'free state' symbol (circle with the letter F) indicate in a GD&T callout?

The feature is a free-turning axis
The part must be inspected while clamped
The tolerance applies only at room temperature
The tolerance applies after release from manufacturing fixturing (Correct answer)

Correct answer: The tolerance applies after release from manufacturing fixturing

The free state modifier indicates that the geometric tolerance applies to the part in its unconstrained, free state — not held in a fixture.

Question 112: When inspecting total runout on a stepped shaft, how many dial indicator passes are required?

Two passes — one clockwise, one counterclockwise
One pass across the entire controlled surface (Correct answer)
As many passes as there are diameter changes, averaged together
One pass per step, each reset to zero

Correct answer: One pass across the entire controlled surface

Total runout requires the indicator to traverse the entire controlled surface in a single continuous sweep while the part rotates.

Question 113: According to ASME Y14.5, which rule governs the relationship between size tolerance and form tolerance for an individual feature of size?

Rule #4 (Virtual Condition)
Rule #3 (Datum Precedence)
Rule #1 (Envelope Principle) (Correct answer)
Rule #2 (RFS Default)

Correct answer: Rule #1 (Envelope Principle)

Rule #1 (the Envelope Principle) states that the form of an individual feature of size must be within a perfect geometric envelope at MMC.

Question 114: Under ASME Y14.5-2018, which modifier can be applied to straightness of a derived median line to allow additional tolerance?

Maximum Material Condition (MMC) or Least Material Condition (LMC) (Correct answer)
Least Material Condition (LMC) only
Free State (F) only
Projected Tolerance Zone (P) only

Correct answer: Maximum Material Condition (MMC) or Least Material Condition (LMC)

Straightness of a derived median line may use MMC or LMC modifiers to grant bonus tolerance as the feature departs from the specified material condition.

Question 115: Under ASME Y14.5, a composite feature control frame is distinguished from a two single-segment frame by:

The composite frame applies only to cylindrical features
The composite frame uses one geometric characteristic symbol spanning both rows (Correct answer)
The composite frame uses two separate geometric characteristic symbols
The composite frame requires MMC in both segments

Correct answer: The composite frame uses one geometric characteristic symbol spanning both rows

A composite frame has a single geometric characteristic symbol (e.g., position circle) that extends vertically across both rows, while a two single-segment frame repeats the symbol in each row independently.

Question 116: A profile tolerance applied to a conical surface primarily replaces which combination of traditional tolerances?

Angularity and cylindricity (Correct answer)
Straightness and circularity
Parallelism and position
Perpendicularity and flatness

Correct answer: Angularity and cylindricity

Profile of a surface on a cone effectively controls both the angle (similar to angularity) and the roundness/form (similar to cylindricity) of the conical surface simultaneously.

Question 117: In a composite profile callout, the lower-segment tolerance zone is described as a uniform-width band. This band is allowed to:

Expand beyond the upper-segment band
Translate and/or rotate relative to the true profile, within limits set by the upper segment (Correct answer)
Change shape relative to the nominal profile
Apply only to internal profiles

Correct answer: Translate and/or rotate relative to the true profile, within limits set by the upper segment

The lower-segment profile tolerance zone can translate and rotate relative to the true profile position, but it must remain entirely within the upper-segment tolerance zone.

Question 118: What is the purpose of a profile of a surface in GD&T?

To define the roundness of a feature.
To define the feature’s size.
To define the flatness of a surface.
To control the outline of a feature. (Correct answer)

Correct answer: To control the outline of a feature.

Profile of a surface is a GD&T tolerance that defines a 3D tolerance zone along the entire surface of a feature. It controls the shape, size, orientation, and location of complex or irregular surfaces, ensuring that the actual surface does not deviate beyond the specified boundaries. This is particularly useful for features that cannot be easily defined by other geometric tolerances.

Question 119: A drawing calls out a perpendicularity tolerance for the axis of a hole. A diameter symbol (⌀) is included before the tolerance value in the feature control frame. What does this indicate?

The measurement must be taken using a cylindrical gage pin.
The tolerance applies to the circularity of the hole.
The tolerance zone is a cylinder within which the axis of the hole must lie. (Correct answer)
The tolerance only applies at the maximum material condition of the hole.

Correct answer: The tolerance zone is a cylinder within which the axis of the hole must lie.

When an orientation tolerance like perpendicularity is applied to a feature of size (such as a hole's axis), the inclusion of a diameter symbol (⌀) in the feature control frame specifies a cylindrical tolerance zone. The axis of the feature must be contained within this cylindrical zone, which is oriented perpendicular to the specified datum.

Question 120: Datum targets are used primarily when:

The datum feature surface is irregular, large, or warped (Correct answer)
Multiple parts are stacked together
The part is made of plastic only
The part has perfectly flat surfaces

Correct answer: The datum feature surface is irregular, large, or warped

Datum targets (points, lines, or areas) are used when full-surface contact is impractical due to surface irregularities, large surfaces, or casting/forging conditions.

Question 121: The 'between' symbol in GD&T notation is used to indicate:

A datum target area
A tolerance applies to the entire surface
A simultaneous requirement
A tolerance applies between two specified points (Correct answer)

Correct answer: A tolerance applies between two specified points

The 'between' symbol (↔) specifies that a tolerance zone is limited to the area between two identified points on a feature.

Question 122: When is it most appropriate to invoke the LMC modifier instead of MMC on a hole?

When the hole must meet Rule #1 perfect form
When maximum bonus tolerance for assembly is needed
When a functional go gauge is required
When the design concern is minimum wall thickness or edge distance rather than assembly clearance (Correct answer)

Correct answer: When the design concern is minimum wall thickness or edge distance rather than assembly clearance

LMC is chosen when the critical design concern is preserving enough material at the edge of a hole, not the assembly clearance.

Question 123: When inspecting a feature using a functional (hard) gauge designed for an MMC position callout, a part that passes the gauge is considered:

Acceptable for the virtual condition boundary requirement only; size still needs separate verification (Correct answer)
Rejected because gauges only identify non-conformance
Acceptable without needing to check actual mating size
Acceptable for all geometric requirements

Correct answer: Acceptable for the virtual condition boundary requirement only; size still needs separate verification

A functional gauge verifies the virtual condition (worst-case boundary) but does not verify the size tolerance, which requires a separate attribute or variable measurement.

Question 124: When a profile of a surface tolerance is used to control a flat planar surface (instead of flatness), what additional control does profile provide over flatness?

Profile controls form only, same as flatness
Profile only applies to curved surfaces, not flat ones
Profile can also control orientation and location when datums are referenced (Correct answer)
Profile requires more measurement points than flatness

Correct answer: Profile can also control orientation and location when datums are referenced

Unlike flatness (form only), profile of a surface with datum references can simultaneously control the orientation and location of a flat surface in addition to its form.

Question 125: A shaft has a total runout tolerance of 0.05 mm. During inspection, the FIM (Full Indicator Movement) reading is 0.04 mm. The part is:

Accepted because the FIM is within the 0.05 mm tolerance (Correct answer)
Rejected because total runout requires zero FIM
Accepted only if re-measured on a different datum
Rejected because FIM must be exactly equal to the tolerance

Correct answer: Accepted because the FIM is within the 0.05 mm tolerance

The part passes because the measured FIM of 0.04 mm is less than the specified total runout tolerance of 0.05 mm.

Question 126: For an external feature (pin) at MMC with a position tolerance, virtual condition equals:

LMC plus the geometric tolerance
LMC minus the geometric tolerance
MMC plus the geometric tolerance (Correct answer)
MMC minus the geometric tolerance

Correct answer: MMC plus the geometric tolerance

For a pin (external feature), virtual condition = MMC + geometric tolerance, giving the largest boundary the pin can occupy.

Question 127: Concentricity is removed from ASME Y14.5-2018. What control replaces it for most design intents?

Position with median points notation
Coaxiality using position (Correct answer)
Runout
Symmetry

Correct answer: Coaxiality using position

ASME Y14.5-2018 removed concentricity and recommends using position applied to the axis (coaxiality) as a more verifiable replacement.

Question 128: A shaft and hole assembly uses an interference fit. Which surface finish condition on the shaft would MOST likely cause the interference to be less than intended?

A surface with a lay perpendicular to the shaft axis
Surface peaks (asperities) that are flattened during pressing (Correct answer)
Surface that is too smooth
Surface that has deep valleys

Correct answer: Surface peaks (asperities) that are flattened during pressing

When pressing an interference fit, surface peaks are crushed and flattened, effectively reducing the interference and the resulting holding force.

Question 129: What does it mean when a datum reference is labeled with [CF] (Continuous Feature)?

The datum must be verified with a CMM
Two or more interrupted features are treated as one datum feature (Correct answer)
The datum applies only to continuous machined surfaces
The datum tolerance is continuous across all zones

Correct answer: Two or more interrupted features are treated as one datum feature

The [CF] modifier indicates that two or more separated (interrupted) features are treated as a single, continuous datum feature for establishing the datum.

Question 130: When a runout tolerance is applied to a conical surface, what does the tolerance zone represent?

Two coaxial cylinders
Two parallel planes perpendicular to the axis
Two lines along the cone surface separated by the tolerance value (Correct answer)
A cylindrical zone centered on the datum axis

Correct answer: Two lines along the cone surface separated by the tolerance value

For conical surfaces, the runout tolerance zone consists of two lines on the cone surface separated by the tolerance value, measured perpendicular to the surface.

Question 131: What is the key geometric difference between the PLTZF and FRTZF tolerance zones?

PLTZF uses unilateral tolerance; FRTZF uses bilateral tolerance
PLTZF zones apply at LMC; FRTZF zones apply at MMC
PLTZF zones are cylindrical; FRTZF zones are spherical
PLTZF zones are fixed in space relative to datums; FRTZF zones can translate as a group (Correct answer)

Correct answer: PLTZF zones are fixed in space relative to datums; FRTZF zones can translate as a group

The PLTZF zones are located at true position relative to the datum reference frame, while the FRTZF zones can translate as a group but must maintain their internal pattern geometry.

Question 132: A hole has a position tolerance of ⌀0.4 at MMC. The actual hole diameter is 10.3 mm and MMC is 10.0 mm. What is the total allowable position tolerance?

⌀0.7 (Correct answer)
⌀0.4
⌀0.3
⌀1.0

Correct answer: ⌀0.7

At MMC the tolerance is ⌀0.4; the hole is 0.3 mm larger than MMC, so bonus tolerance adds 0.3, giving ⌀0.7 total.

Question 133: Two parts share the same datum reference frame for mating. Part A's position is called out as ⊕|Ø0.020|A|B|C. If datum B is referenced at MMC and Part A's datum B feature is at LMC, what is the maximum datum shift?

Half the position tolerance
Zero, because LMC eliminates shift
The difference between LMC and MMC of the datum B feature (Correct answer)
The total position tolerance value

Correct answer: The difference between LMC and MMC of the datum B feature

Maximum datum shift occurs when the datum feature is at LMC; shift equals the full difference between LMC and MMC of the datum feature.

Question 134: In a bolted joint assembly, if the mating surfaces have excessive waviness (long-wavelength deviations), the primary risk is:

Improved sealing without a gasket
Uneven clamp load distribution and potential fatigue cracking (Correct answer)
Increased friction during assembly
Higher surface roughness measurement

Correct answer: Uneven clamp load distribution and potential fatigue cracking

Waviness creates gaps and high-pressure contact zones in bolted joints, causing uneven clamping forces that accelerate fatigue failure.

Question 135: A designer needs to control the form of a cylindrical pin to ensure it is both round and straight along its entire length. Which single GD&T symbol provides this three-dimensional control?

Circularity
Cylindricity (Correct answer)
Straightness
Profile of a Surface

Correct answer: Cylindricity

Cylindricity is a 3D form control that simultaneously manages the roundness and straightness of a cylindrical feature. It defines a tolerance zone bounded by two coaxial cylinders within which the entire surface of the feature must lie. Circularity, by contrast, is a 2D control applied to individual cross-sections.

Question 136: Which symbol, when placed below a feature control frame, indicates that the tolerance applies to the entire length or surface — not per unit?

The 'T' symbol for total
An underline beneath the frame
An 'E' modifier in the frame
No additional symbol is needed; it applies to the entire extent by default (Correct answer)

Correct answer: No additional symbol is needed; it applies to the entire extent by default

By default, a geometric tolerance applies to the full extent of the feature unless a 'per unit' basis is specified separately below the frame.

Question 137: Rule #2 in ASME Y14.5 states that unless otherwise specified, each tolerance of orientation, form, location, or runout applies to which condition?

Maximum Material Condition (MMC)
Regardless of Feature Size (RFS) (Correct answer)
Free State (FST)
Least Material Condition (LMC)

Correct answer: Regardless of Feature Size (RFS)

Rule #2 (RFS) is the default condition — geometric tolerances apply regardless of actual feature size unless MMC or LMC is specified.

Question 138: What is a basic dimension on an engineering drawing?

A reference-only dimension with no tolerance
A theoretically exact value, shown in a rectangular box, used to define the perfect geometry from which GD&T tolerance zones are measured (Correct answer)
A dimension used exclusively for functional gauging
A dimension carrying the standard ±0.010 title-block tolerance

Correct answer: A theoretically exact value, shown in a rectangular box, used to define the perfect geometry from which GD&T tolerance zones are measured

Basic dimensions (shown boxed) are perfect, zero-tolerance values that locate or orient GD&T tolerance zones; all tolerance is captured in the feature control frame, not the dimension itself.

Question 139: In a Feature Control Frame, which of the following symbols is used to control the 3-dimensional form of any surface, including complex, curved, or irregular shapes, relative to a true profile?

Profile of a Surface (Correct answer)
Flatness
Total Runout
Profile of a Line

Correct answer: Profile of a Surface

The Profile of a Surface symbol is used to control the form and orientation of a 3D surface relative to its true profile. It creates a uniform tolerance boundary on either side of the desired surface contour, making it extremely versatile for controlling complex geometries. Profile of a Line is a 2D control for cross-sections only.

Question 140: In GD&T, 'simultaneous requirements' for datum features means:

Primary and secondary datums are interchangeable
The datum features must have identical tolerance values
All datum features must be inspected at the same time on a CMM
Multiple geometric tolerances sharing the same DRF are verified as a single pattern (Correct answer)

Correct answer: Multiple geometric tolerances sharing the same DRF are verified as a single pattern

Simultaneous requirements means that multiple features or patterns referencing the same datum reference frame in the same order are treated as a single pattern during verification.

Question 141: What does Rule #1 (the Envelope Principle) state in ASME Y14.5?

A feature of size's surface must not violate a perfect-form envelope at MMC (Correct answer)
All tolerances must be measured at LMC
Datums must always be labeled in A-B-C order
Geometric tolerances are mandatory on every drawing

Correct answer: A feature of size's surface must not violate a perfect-form envelope at MMC

Rule #1 requires that a feature of size controlled only by size tolerances must not violate a perfect-form (zero geometric error) boundary when the feature is at MMC.

Question 142: An MMC modifier is applied to the FRTZF of a composite position callout. What benefit does this provide?

It allows the PLTZF to increase
It provides bonus tolerance for feature-to-feature location as features depart from MMC (Correct answer)
It eliminates the need for the PLTZF
It restricts the tolerance to the minimum material condition only

Correct answer: It provides bonus tolerance for feature-to-feature location as features depart from MMC

An MMC modifier on the FRTZF allows each feature's tolerance zone to increase (bonus tolerance) as the feature departs from MMC, while still maintaining pattern geometry.

Question 143: What does 'datum shift' allow when a datum feature is referenced at MMC?

Additional tolerance as the datum feature departs from MMC (Correct answer)
The datum feature to move out of the tolerance zone
The tolerance zone shifts toward the datum
The feature to ignore the datum reference

Correct answer: Additional tolerance as the datum feature departs from MMC

Datum shift is bonus movement allowed between the part datum feature and the datum feature simulator when the feature departs from its MMC size.

Question 144: In a datum reference frame, what is the maximum number of degrees of freedom that can be constrained?

3
4
6 (Correct answer)
9

Correct answer: 6

A complete datum reference frame constrains all 6 degrees of freedom: 3 translational and 3 rotational.

Question 145: When verifying composite position with a functional gauge, which segment drives the gauge hole locations?

The gauge only verifies the larger of the two tolerances
Both segments are checked with a single gauge simultaneously
The PLTZF drives the absolute pattern location; a separate gauge checks FRTZF (Correct answer)
The FRTZF always drives gauge hole locations

Correct answer: The PLTZF drives the absolute pattern location; a separate gauge checks FRTZF

A PLTZF functional gauge locates holes at true position relative to the datum reference frame; a separate FRTZF gauge checks the feature-to-feature geometry with holes at the FRTZF tolerance size.

Question 146: When a cylindrical feature is used as a primary datum, it constrains how many degrees of freedom?

Four (Correct answer)
Six
Three
Two

Correct answer: Four

A cylindrical primary datum constrains four degrees of freedom: two translations perpendicular to its axis and two rotations perpendicular to its axis.

Question 147: When interpreting a composite feature control frame, what is the term for the tolerance zone defined by the upper segment?

Feature-Relating Tolerance Zone Framework (FRTZF)
Secondary Tolerance Zone Framework (STZF)
Pattern-Locating Tolerance Zone Framework (PLTZF) (Correct answer)
Datum-Relating Tolerance Zone Framework (DRTZF)

Correct answer: Pattern-Locating Tolerance Zone Framework (PLTZF)

According to the ASME Y14.5 standard, the upper segment of a composite feature control frame establishes the Pattern-Locating Tolerance Zone Framework (PLTZF). This framework controls the location of the entire pattern of features as a group relative to the specified datums. The lower segment establishes the Feature-Relating Tolerance Zone Framework (FRTZF).

Question 148: What effect does surface roughness have on runout measurement?

Rough surfaces reduce FIM readings by absorbing indicator tip movement
High surface roughness can artificially increase the FIM reading beyond actual geometric error (Correct answer)
Surface roughness only affects total runout, not circular runout
Surface roughness has no effect on runout readings

Correct answer: High surface roughness can artificially increase the FIM reading beyond actual geometric error

A rough surface can cause the dial indicator tip to bounce or skip, inflating the FIM reading beyond the true geometric runout error.

Question 149: Datum shift is allowed when which modifier is applied to a datum feature of size?

Least Material Condition (LMC)
Both MMC and LMC, but not RFS (Correct answer)
Maximum Material Condition (MMC)
Regardless of Feature Size (RFS)

Correct answer: Both MMC and LMC, but not RFS

Datum shift is available when either MMC or LMC is applied to a datum feature of size reference; RFS requires the datum to be derived without shift.

Question 150: When referencing a datum feature of size at RFS (regardless of feature size), datum shift is:

Zero — no datum shift is permitted (Correct answer)
Equal to the MMC bonus tolerance
Equal to the feature tolerance
Calculated from the LMC boundary

Correct answer: Zero — no datum shift is permitted

At RFS, the datum feature simulator expands or contracts to make contact with the actual feature, so no datum shift is allowed.

Question 151: In a datum reference frame, what does the term 'degrees of freedom' refer to?

The number of tolerances on a drawing
The number of datum features required
The range of acceptable part sizes
The independent modes of translation and rotation of a part in space (Correct answer)

Correct answer: The independent modes of translation and rotation of a part in space

Degrees of freedom are the six independent ways a rigid body can move in 3D space: three translations (X, Y, Z) and three rotations (u, v, w).

Question 152: When does a title-block general tolerance apply to a dimension on an engineering drawing?

When the dimension has no explicit tolerance callout and is not a basic dimension (Correct answer)
When the dimension controls a datum feature
When the dimension is identified as a reference dimension
When a feature control frame is attached to the dimension

Correct answer: When the dimension has no explicit tolerance callout and is not a basic dimension

Title-block general tolerances provide a default for any dimension that lacks its own explicit tolerance; basic dimensions (boxed) are excluded because their tolerance is defined by the associated feature control frame.

Question 153: A form or orientation tolerance callout that includes a free-state modifier (F) indicates the measurement should be taken:

While the part is restrained in a fixture
At maximum material condition
After heat treatment
Without any restraining forces applied (in its free state) (Correct answer)

Correct answer: Without any restraining forces applied (in its free state)

The free-state modifier indicates the tolerance applies when the part is in its unrestrained, natural condition without any fixturing forces.

ASME GDTP Geometric Dimensioning and Tolerancing Professional Exam

The ASME GDTP (Geometric Dimensioning and Tolerancing Professional) Technologist exam is a 150-question, multiple-choice certification test based on the ASME Y14.5-2009 standard. Candidates have 4 hours to complete the exam. A passing score requires at least 78% overall and at least 50% in each of the 9 content domains, which cover scope and definitions, general tolerancing, symbology, datum reference frames, tolerances of form, orientation, location, profile, and runout. The exam is administered by ASME and is widely recognized in manufacturing, aerospace, and mechanical engineering industries.

150

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240 min

Time Limit

78%

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