18 Print Reading & GD&T Practice Questions & Answers

1. 1. On a machining print, a thin line drawn as long dash, short dash, long dash is used for every purpose below EXCEPT which one?

   • A.Showing an edge that is hidden behind material in that view✓ Answer
   • B.Locating the axis of a drilled hole or of a turned diameter
   • C.Marking the line of symmetry of a symmetrical part
   • D.Showing the bolt-circle path on which a pattern of holes is equally spaced around a hub

   The long-short-long thin line is a centerline, and its job is to locate axes, symmetry and bolt circles. An edge concealed behind material is drawn with a medium-weight dashed hidden line, so a centerline can never carry hidden detail.

   Source: ASME Y14.2 line conventions (centerline vs. hidden line); NIMS Print Reading competency "Line Types and Conventions"Report a problem with this question

2. 2. A visible edge, a hidden edge and a centerline all fall at exactly the same place in one view. Which line is actually drawn there?

   • A.The centerline, because the other features are located from it and it therefore takes priority
   • B.The visible (object) line✓ Answer
   • C.The hidden line, because internal detail must never be lost from a view of the part
   • D.Whichever line the drafter judges least confusing, since precedence is left to company practice

   Line precedence is fixed: a visible line outranks a hidden line, and a hidden line outranks a centerline (a cutting-plane line also outranks a centerline). Only the highest-ranking line is drawn, because the outline of the part must never be obscured by a lower-ranking line.

   Source: ASME Y14.2 line precedence: visible line over hidden line over centerlineReport a problem with this question

3. 3. A U.S. shop print carries the third-angle projection symbol in the title block. In the three-view drawing, where do the top view and the right-side view appear relative to the front view?

   • A.Top view below the front view and right-side view to the left, which is the arrangement used on prints drawn to ISO first-angle practice
   • B.Top view above and right-side view to the left, mirroring the part across the vertical centerline of the sheet
   • C.Top view directly above the front view, and the right-side view to the right of the front view✓ Answer
   • D.Anywhere convenient on the sheet, provided each view is labeled with its name near the border

   In third-angle projection, used on U.S./ASME prints, each view is placed on the same side as the direction from which it is viewed, so the top view lands above the front view and the right-side view lands to the right. First-angle projection, identified by the other truncated-cone symbol, reverses both placements.

   Source: ASME Y14.3 third-angle orthographic projection (U.S. practice); projection symbol in the title blockReport a problem with this question

4. 4. A full section is taken through a part. What do the arrowheads at the ends of the cutting-plane line tell the reader?

   • A.The direction in which the section lines (crosshatch) must be drawn on the exposed material
   • B.The location of the datum planes used to inspect the internal features that the section exposes
   • C.The order in which the machinist should remove the material that the section shows as cut away
   • D.The direction of sight, that is, which side of the cut the section view shows✓ Answer

   The cutting-plane line shows where the imaginary cut is made and the arrows point in the direction the observer looks; everything between the observer and the cutting plane is imagined removed. That is why hidden lines in the exposed area are replaced by visible lines and crosshatch.

   Source: ASME Y14.3 section views: cutting-plane line arrowheads indicate the direction of sightReport a problem with this question

5. 5. A title block reads: .X ±.1, .XX ±.01, .XXX ±.005. On the same print one dimension is given as 1.250 ±.002 and another as 2.75 with no tolerance shown. What are the limits of the two dimensions?

   • A.1.248–1.252 and 2.74–2.76✓ Answer
   • B.1.245–1.255 and 2.74–2.76
   • C.1.248–1.252 and 2.745–2.755
   • D.1.245–1.255 and 2.745–2.755, because the tightest tolerance printed in the block governs every dimension on the drawing

   The block tolerance applies only where no tolerance is written on the dimension itself, and it is keyed to the number of decimal places. The 1.250 dimension carries its own ±.002, which overrides the block, while the two-place 2.75 takes the .XX value of ±.01.

   Source: Title-block (general/block) tolerance practice: a tolerance specified on the dimension overrides the block tolerance, which is keyed to decimal placesReport a problem with this question

6. 6. A dimension on a print appears in parentheses, for example (4.500). How must the machinist treat it?

   • A.As a basic dimension, whose only permitted variation comes from the geometric tolerance in a feature control frame
   • B.As information only: it repeats or sums other dimensions already given on the print, so it carries no tolerance of its own and is never produced to or inspected✓ Answer
   • C.As a maximum value that the finished feature may not exceed under any condition
   • D.As the first dimension to be measured, since parentheses identify the dimension the inspection setup is established from

   Parentheses identify a reference dimension. Its value is derived from other dimensions already given on the print, so it carries no tolerance of its own and is never used to make or accept the part; a dimension enclosed in a rectangular box, by contrast, is basic.

   Source: ASME Y14.5 reference dimension (value shown in parentheses) vs. basic dimension (value shown in a box)Report a problem with this question

7. 7. A surface texture symbol on a print has a horizontal bar added across the top of the check mark, with 32 shown at the upper left. What does the callout require?

   • A.Material removal is prohibited; the surface must be left as cast or as forged
   • B.The surface may be no smoother than 32 µin, so grinding, honing or lapping the face would put the part out of tolerance
   • C.Material removal by machining is required, and the roughness average must not exceed 32 µin Ra✓ Answer
   • D.32 is the waviness height, and the bar identifies the lay, that is, the direction of the predominant tool marks

   The bar added across the surface texture symbol means material removal by machining is required, while a circle placed in the vee means removal is prohibited. The number at the upper left is the maximum Ra in microinches, so a smaller measured value is smoother and still acceptable.

   Source: ASME Y14.36 surface texture symbols: horizontal bar = material removal required; circle = removal prohibited; value at upper left = maximum RaReport a problem with this question

8. 8. In a position feature control frame the tolerance compartment reads ⌀.014. What does the diameter symbol placed ahead of the value do?

   • A.Nothing; it simply repeats the diameter of the hole that is being controlled
   • B.It doubles the tolerance, because a diameter zone permits twice the radial deviation from true position
   • C.It leaves the shape of the zone unchanged but requires the feature to be inspected at maximum material condition, which adds bonus tolerance
   • D.It makes the tolerance zone a cylinder .014 across instead of two parallel planes .014 apart✓ Answer

   The diameter symbol in the tolerance compartment defines the shape of the tolerance zone. With it, the axis of the hole must lie inside a cylinder of that diameter centered on true position; without it, the zone is only two parallel planes and the feature is controlled in a single direction.

   Source: ASME Y14.5 feature control frame: diameter symbol in the tolerance compartment denotes a cylindrical tolerance zoneReport a problem with this question

9. 9. A print shows a flatness callout whose feature control frame also lists a datum reference A. Why is that frame wrong?

   • A.Flatness is a form tolerance, and form tolerances control the feature relative to itself, so the zone floats with the surface and no datum can be referenced✓ Answer
   • B.Flatness may reference only a datum axis, so the letter would have to identify a cylindrical feature
   • C.Flatness requires a complete datum reference frame, so one letter alone is not enough
   • D.Flatness may reference a datum only when an MMC modifier is also placed in the tolerance compartment of the same frame, which this callout does not show

   The form category — straightness, flatness, circularity and cylindricity — controls a feature's shape relative to itself, so the tolerance zone floats with the surface and no datum is possible. Orientation, location and runout are the categories that do require datum references.

   Source: ASME Y14.5 form tolerances (straightness, flatness, circularity, cylindricity) take no datum referenceReport a problem with this question

10. 10. One print controls a hole with a position frame reading ⌀.010 to A, B, C; another controls the same hole reading ⌀.010 to B, A, C. What is the practical difference?

    • A.None; datum letters in a feature control frame are read alphabetically, so both frames set up exactly the same datum reference frame
    • B.Datum precedence differs: the primary datum feature is contacted first at three points, so each frame seats the part differently and requires a different setup✓ Answer
    • C.The second frame is invalid, because datum letters must always be listed in alphabetical order
    • D.Only the machining sequence differs; the letters simply record which surfaces were finished before the hole was drilled

    Precedence is set by the order the letters appear, not by the alphabet. The primary datum feature is contacted first at a minimum of three points, then the secondary at two, then the tertiary at one; swapping A and B seats the part differently, so the same hole can pass one callout and fail the other.

    Source: ASME Y14.5 datum precedence: primary, secondary and tertiary order as listed in the feature control frameReport a problem with this question

11. 11. Under the 3-2-1 rule, how many of a rigid part's six degrees of freedom does the primary datum plane constrain?

    • A.One translation only, leaving five degrees of freedom to be removed by the remaining datum features
    • B.All six, which is why the secondary and tertiary datum features serve only for reference
    • C.Three — one translation and two rotations, removed by contact at a minimum of three points — leaving three for the secondary and tertiary datums✓ Answer
    • D.Two rotations, leaving four degrees of freedom for the secondary and tertiary datum features to remove

    A rigid part has six degrees of freedom: three translations and three rotations. The primary datum plane contacts a minimum of three points and removes one translation plus two rotations; the secondary contacts two points and removes two more; the tertiary contacts one point and removes the last one.

    Source: ASME Y14.5 datum reference frame: 3-2-1 rule and the six degrees of freedom of a rigid partReport a problem with this question

12. 12. A hole is dimensioned ⌀.500–.510 and carries a position tolerance of ⌀.010 at MMC to datums A, B, C. The finished hole measures ⌀.508. How much position tolerance is available?

    • A.⌀.010, because the value stated in the feature control frame may never be increased
    • B.⌀.012
    • C.⌀.020, because the stated zone doubles as soon as the feature departs from maximum material condition
    • D.⌀.018 — the .008 by which the hole departs from its MMC size of ⌀.500 is added as bonus tolerance✓ Answer

    For a hole, MMC is the smallest size, ⌀.500. The hole was produced at ⌀.508, a departure of .008 from MMC, and that departure is added to the stated tolerance as bonus tolerance: .010 + .008 = ⌀.018.

    Source: ASME Y14.5 maximum material condition modifier: bonus tolerance equals the departure of the actual mating size from MMCReport a problem with this question

13. 13. A position frame reads ⌀.014 at MMC to datums A, B at MMC, and C. What does the MMC modifier that follows datum B provide?

    • A.Datum shift: the datum feature simulator is made at B's virtual condition, so the part may move within it as B departs from MMC, while the ⌀.014 zone itself does not grow✓ Answer
    • B.Extra position tolerance added to the .014 zone as datum feature B departs from MMC
    • C.Nothing; a material condition modifier has meaning only in the tolerance compartment
    • D.It requires datum feature B to be inspected at its least material condition, which enlarges the gage element used to seat the part

    A modifier in the tolerance compartment produces bonus tolerance and enlarges the zone. The same modifier applied to a datum feature of size produces datum shift instead: the simulator or gage element is made at B's virtual condition, so the part can move relative to it, but the ⌀.014 zone itself does not grow.

    Source: ASME Y14.5: material condition modifier in the tolerance compartment gives bonus tolerance; applied to a datum feature of size it gives datum shiftReport a problem with this question

14. 14. A shaft is dimensioned ⌀1.000–1.005 and no straightness or other form tolerance appears anywhere on the print. What controls the form of that shaft?

    • A.Nothing; with no form callout, bow or barrel shape is unlimited as long as every diameter measured falls inside the size limits
    • B.The size limits themselves: the shaft must fit inside a perfect-form boundary at its MMC of ⌀1.005✓ Answer
    • C.The angular tolerance in the title block, which applies to any feature carrying no geometric callout
    • D.The general note requiring all surfaces to be square and true, which is understood on every machining print

    Rule #1, the envelope principle, states that where only a size tolerance is given, the limits of size also control form. The feature must fit a perfect-form envelope at MMC, and the permissible form error grows toward the full size tolerance only as the shaft approaches LMC.

    Source: ASME Y14.5 Rule #1 (envelope principle / Taylor principle): limits of size control form where no form tolerance is specifiedReport a problem with this question

15. 15. Inspection of a hole located by basic dimensions finds the axis .003 off in X and .004 off in Y. What position deviation is compared with the diameter tolerance zone in the feature control frame?

    • A.⌀.005, the radial distance from true position to the actual axis
    • B.⌀.007, the two coordinate deviations added together
    • C.⌀.010, twice the radial distance, because the zone is stated as a diameter✓ Answer
    • D.⌀.014, the radial distance multiplied by the number of coordinate directions checked

    The coordinate deviations give a radius: the square root of (.003² + .004²) equals .005. Because the position tolerance is stated as a diameter, that radius must be doubled — 2 × .005 = ⌀.010 — before it is compared with the zone; omitting the factor of two is the most common error in this conversion.

    Source: ASME Y14.5 position tolerancing: diametral position deviation = 2 × √(ΔX² + ΔY²)Report a problem with this question

16. 16. A shaft journal must run true to datum axis A along its entire length, with no wobble at any point and no taper or barrel shape. Which control states that requirement?

    • A.Circular runout, which is evaluated separately at each single cross-section as the part is rotated
    • B.Cylindricity, with datum A referenced in the last compartment of the feature control frame
    • C.Concentricity at MMC, the callout that current drawing practice uses for rotating shaft surfaces
    • D.Total runout, since the indicator reading is taken across the whole surface as the part rotates✓ Answer

    Total runout applies the full indicator reading across the whole surface while the part rotates about the datum axis, so it controls circularity, straightness, taper and coaxiality at once. Circular runout checks only one cross-section at a time, cylindricity is a form control that cannot reference a datum, and concentricity has been withdrawn from current practice.

    Source: ASME Y14.5 runout tolerances: circular runout evaluated per cross-section vs. total runout evaluated over the entire surfaceReport a problem with this question

17. 17. An inspector is building a checklist from a GD&T print. A hole is located by boxed dimensions of 1.500 and 2.000 and carries a position feature control frame. How is that location verified?

    • A.Against the position tolerance zone in the feature control frame alone, since a boxed dimension is basic and is deliberately not toleranced by the title block, with the part set up on the datums in the order listed✓ Answer
    • B.Measure 1.500 and 2.000 with a height gage and apply the .XXX tolerance from the title block
    • C.It is not checked at all, since boxed dimensions are reference values shown only for programming
    • D.Add the block tolerance to the position tolerance, because both apply to a boxed dimension on a GD&T print and the looser of the two governs acceptance

    A boxed dimension is basic: it is theoretically exact and deliberately not toleranced by the title block. The only permissible variation is the tolerance zone in the feature control frame, located from the datum reference frame in the order the datum letters appear.

    Source: ASME Y14.5 basic dimension: theoretically exact, toleranced only by the geometric tolerance in the feature control frameReport a problem with this question

18. 18. A surface carries a 63 µin Ra requirement. Which method is appropriate to verify it?

    • A.A 0–1 in micrometer with a .0001 in vernier, reading peak-to-valley height directly off the finished surface
    • B.A roughness comparison specimen or a profilometer✓ Answer
    • C.A height gage on a surface plate, sweeping an indicator across the face and recording the total indicator reading as Ra
    • D.A go/no-go plug gage of the matching class, since finish is a gaged characteristic like a threaded hole

    Ra is the arithmetic average height of the surface's micro-irregularities over a sampling length, measured in microinches. It is assessed by comparing the surface against a calibrated roughness specimen or by tracing it with a profilometer stylus; general-purpose size instruments such as micrometers, height gages and plug gages cannot resolve or report Ra.

    Source: ASME B46.1 / Y14.36 surface texture verification: roughness comparison specimen or profilometer measurement of RaReport a problem with this question

Practice questions based on NIMS/ANSI 101-2001, Duties and Standards for Machining Skills Level I, and the published content of the NIMS Machining Level I theory exams, together with standard precision-machining practice. NIMS is a mark of the National Institute for Metalworking Skills; this site is not affiliated with or endorsed by NIMS. Machining Level I is a set of separate credentials, and most of them also require a hands-on performance test that this bank does not cover. The NIMS theory exams are open-reference, but questions here never depend on recalling a handbook table value, a citation number or a machine rating — always work from the print in front of you, your employer's written procedures, and the machine's own documentation, and confirm current requirements before testing. About the NIMS machining credentials →