Free GDTP Practice Questions

Question 1

A bracket has a clearance-hole pattern with hole diameters of 8.00-8.25 mm and a diametrical position tolerance of 0.20 mm at MMC to A | B | C. The three datums are mutually perpendicular planar surfaces. A toolmaker proposes interchangeable checking pins selected for each measured hole diameter. Assume exact datum simulators and pins at the basic hole locations; disregard gagemaker tolerances and wear allowances. Which fixed pin diameter instead represents the positional acceptance boundary as hole size varies?

Accepted Answer

Diameter 7.80 mm, unchanged as a larger hole gains positional tolerance.

Answer

Diameter 8.00 mm, holding each hole to its maximum-material size.

Answer

Diameter 8.05 mm, using the largest hole minus its position tolerance.

Answer

Diameter 8.20 mm, enlarging the minimum hole diameter by the full positional tolerance.

Question 2

An instrument housing is pulled firmly against its mating plate by bolts. Its mounting face is A. A short cylindrical pilot B provides lateral location but cannot override face seating; a radial slot C establishes clocking. Inspection must reproduce this assembly even when the pilot and face are not exactly square. Specify the datum-reference order for locating the bolt-hole pattern.

Accepted Answer

A | B | C

Answer

B | A | C

Answer

A | C | B

Answer

B | C | A

Question 3

Every local two-point diameter on a rigid machined shaft is between 19.90 and 20.00 mm, matching its size limits. The smallest perfect cylinder enclosing the entire shaft is diameter 20.04 mm. Its ASME Y14.5M-1994 drawing specifies no axis-straightness tolerance and no exception to the envelope requirement. The supplier argues that the shaft must pass because there is no separate straightness callout. How should it be classified?

Accepted Answer

Nonconforming: its full-length envelope exceeds the 20.00 mm maximum-material boundary.

Answer

Conforming: the 0.10 mm size tolerance supplies additional allowance beyond the maximum-material envelope.

Answer

Conforming: every local diameter meets its limits, and no separate straightness tolerance was specified.

Answer

Undetermined: the envelope must be reinspected relative to a datum axis before form can be judged.

Question 4

A supplier redraws a position callout on an ASME Y14.5M-1994 plate. Originally, one position symbol spans an upper segment of diameter 0.60 | A | B | C and a lower segment of diameter 0.12 | A | B. The supplier repeats the position symbol in the lower segment, creating two single-segment frames. Values are in millimeters and all tolerances are RFS. A is the primary face; B and C are perpendicular side faces. What requirement changes?

Accepted Answer

Basic distance from B is now controlled by the lower frame, in addition to its orientation.

Answer

The lower frame now locates the pattern from C, although C is not repeated.

Answer

Nothing changes; two single-segment frames are equivalent to a composite frame with the same numbers and datum references.

Answer

The lower frame becomes a hole-to-hole spacing control without any orientation relationship to A or B.

Question 5

A cross-drilled passage in a high-pressure hydraulic manifold lies close to an external wall. The passage diameter may vary within its size limits. The geometric specification must preserve the required minimum ligament to that wall while allowing more axis-location error as the passage becomes smaller. The wall and its locating datums are already fully controlled. Which position specification provides that size-dependent protection?

Accepted Answer

Position at LMC, maintaining a fixed outer virtual-condition boundary for the passage.

Answer

Position at RFS, using a fixed zone selected for the smallest permissible passage diameter.

Answer

Position at MMC, maintaining a fixed boundary for clearance to a mating pin.

Answer

Zero position at MMC, permitting additional location error only as the passage diameter increases.

Question 6

An inspection report lists a hole's center offsets as +0.060 mm in X and -0.080 mm in Y from its basic location. The hole is a perfect cylinder, its axis is normal to primary datum A, and no datum displacement is available. Position is specified as diameter 0.24 mm at RFS to A | B | C, and the hole size conforms. Which entry belongs in the disposition report?

Accepted Answer

Position error 0.200 mm; accept the positional requirement.

Answer

Position error 0.100 mm; accept the positional requirement.

Answer

Position error 0.280 mm; reject the positional requirement.

Answer

Position error 0.160 mm; accept the positional requirement.

Question 7

A thin cast cover's drawing specifies datum target areas A1, A2 and A3 on three mounting pads, a clamp sequence, and a maximum clamp force of 30 N. The flange profile is to be inspected in that restrained condition; no free-state profile limit is specified. Following the stated sequence at 24 N, the inspector obtains contact at all three targets and a conforming profile. The cover springs visibly out of shape when released. What disposition is justified for the profile result?

Accepted Answer

Accept the restrained profile result; the prescribed setup and clamp-force limit were satisfied.

Answer

Hold for an engineering ruling; the released cover must also meet the restrained profile limit.

Answer

Reject; visible springback makes the restrained profile result invalid.

Answer

Repeat the inspection at exactly 30 N; a result obtained below the maximum force cannot demonstrate conformance.

Question 8

Positive signed deviations on a formed duct are outward from its basic contour. The ASME Y14.5M-1994 drawing explicitly places a surface-profile zone from -0.05 to +0.25 mm normal to that contour, relative to fully established datums A, B and C. A complete evaluation gives extremes of -0.08 and +0.21 mm; other requirements conform. The supplier requests acceptance because the measured spread is smaller than the 0.30 mm zone width. Which response is technically sound?

Accepted Answer

Reject the profile result; the inward excursion lies outside the explicitly located tolerance zone.

Answer

Accept; profile limits the total surface variation, so its zone may shift to enclose the measured extremes.

Answer

Hold for remeasurement using an equally disposed zone; a 0.30 mm profile tolerance must be centered on the contour.

Answer

Accept; inward deviations do not govern an external surface's profile.

Question 9

Consider this hole-pattern callout: POSITION | diameter 0.18 | A | B(M) | C, in millimeters. Here (M) represents the circled MMC modifier on datum hole B; no material-condition modifier follows 0.18. All hole sizes conform. The datum simulators permit some in-plane part displacement while maintaining contact with A and C. Which inspection approach preserves the specified requirement?

Accepted Answer

Keep each zone diameter at 0.18 mm and evaluate the pattern at one permissible placement of the part.

Answer

Fix the 0.18 mm zones to B's measured axis, eliminating simulator clearance.

Answer

Increase each hole's 0.18 mm tolerance by its own diameter departure from MMC, then keep the datum setup fixed.

Answer

Add B's diametral simulator clearance to every hole's tolerance and assess the holes independently in the centered setup.

Question 10

A cover fits over studs fixed in a base. Each stud can be as large as 6.00 mm and each cover hole as small as 6.60 mm. Stud locations already have a diametrical position tolerance of 0.24 mm at MMC, controlled over the entire projection through the cover. The mating patterns share compatible basic locations and datum schemes. No extra tilt allowance is needed. What is the largest diametrical position tolerance at MMC assignable to the cover holes while preserving theoretical worst-case assembly?

Accepted Answer

0.36 mm, using the clearance remaining after the stud-location allowance.

Answer

0.60 mm, assigning all clearance to the cover.

Answer

0.18 mm, halving the remaining clearance after allowing for the stud pattern's position error.

Answer

0.30 mm, making the tolerance allocation equal.

Free GDTP Practice Questions

Domain 1: Topics from the Technologist's Level examination 10% of exam

Question 1

Domain 2: Datum Selection 20% of exam

Question 2

Question 3

Domain 3: General Tolerancing and Related Principles, Tolerance Calculation and Appendices 40% of exam

Question 4

Question 5

Question 6

Question 7

Domain 4: Application of Modifiers in Feature Control Frames 15% of exam

Question 8

Question 9

Domain 5: Composite Positional Tolerancing 15% of exam

Question 10

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