27 real Limits, Fits & Tolerances questions from the Mechanical Design bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Hole basis system?
Junior
A.letter (uppercase for holes, lowercase for shafts) that fixes the position of the tolerance zone relative to the basic size
B.GO gauge checks all dimensions together as a full-form envelope at MMC, while NO-GO checks each dimension separately at LMC
C.hole kept at H (zero lower deviation) and the fit obtained by varying the shaft, preferred because holes are made with standard drills and reamers
D.shaft always larger than hole, such as H7/p6 for a press fit and H7/s6 for a shrink fit that transmits torque without a key
2. Which term means: "hole kept at H (zero lower deviation) and the fit obtained by varying the shaft, preferred because holes are made with standard drills and reamers"?
A.Hole basis system — shaft always larger than hole, such as H7/p6 for a press fit and H7/s6 for a shrink fit that transmits torque without a key
B.Hole basis system — shaft always smaller than hole, such as H7/g6 for sliding spindles and H8/f7 for running bearings
C.Hole basis system — hole kept at H (zero lower deviation) and the fit obtained by varying the shaft, preferred because holes are made with standard drills and reamers
D.Hole basis system — tolerance grade IT01 to IT18 fixing the width of the zone, with IT5–IT7 for fits, IT8–IT11 for general machining and IT12 upward for raw processes
A.letter (uppercase for holes, lowercase for shafts) that fixes the position of the tolerance zone relative to the basic size
B.arithmetic mean deviation of the profile from its mean line, typically 0.8 µm for ground bearing seats, 1.6 for fine turning and 3.2 for general machining
C.tolerance zones overlap so the assembly may be slightly tight or loose, such as H7/k6 for locating gears and pulleys that also carry a key
D.shaft always larger than hole, such as H7/p6 for a press fit and H7/s6 for a shrink fit that transmits torque without a key
A.Fundamental deviation — letter (uppercase for holes, lowercase for shafts) that fixes the position of the tolerance zone relative to the basic size
B.Fundamental deviation — mean peak-to-valley height over five sampling lengths, about 4–7 times Ra and better at catching isolated scratches on sealing faces
C.Fundamental deviation — hole kept at H (zero lower deviation) and the fit obtained by varying the shaft, preferred because holes are made with standard drills and reamers
D.Fundamental deviation — tolerance zones overlap so the assembly may be slightly tight or loose, such as H7/k6 for locating gears and pulleys that also carry a key
8. Which term means: "tolerance grade IT01 to IT18 fixing the width of the zone, with IT5–IT7 for fits, IT8–IT11 for general machining and IT12 upward for raw processes"?
A.IT grade — shaft always larger than hole, such as H7/p6 for a press fit and H7/s6 for a shrink fit that transmits torque without a key
B.IT grade — arithmetic mean deviation of the profile from its mean line, typically 0.8 µm for ground bearing seats, 1.6 for fine turning and 3.2 for general machining
C.IT grade — tolerance grade IT01 to IT18 fixing the width of the zone, with IT5–IT7 for fits, IT8–IT11 for general machining and IT12 upward for raw processes
D.IT grade — shaft always smaller than hole, such as H7/g6 for sliding spindles and H8/f7 for running bearings
A.Clearance fit — shaft always smaller than hole, such as H7/g6 for sliding spindles and H8/f7 for running bearings
B.Clearance fit — hole kept at H (zero lower deviation) and the fit obtained by varying the shaft, preferred because holes are made with standard drills and reamers
C.Clearance fit — tolerance grade IT01 to IT18 fixing the width of the zone, with IT5–IT7 for fits, IT8–IT11 for general machining and IT12 upward for raw processes
D.Clearance fit — GO gauge checks all dimensions together as a full-form envelope at MMC, while NO-GO checks each dimension separately at LMC
14. Which term means: "tolerance zones overlap so the assembly may be slightly tight or loose, such as H7/k6 for locating gears and pulleys that also carry a key"?
A.Transition fit — arithmetic mean deviation of the profile from its mean line, typically 0.8 µm for ground bearing seats, 1.6 for fine turning and 3.2 for general machining
B.Transition fit — hole kept at H (zero lower deviation) and the fit obtained by varying the shaft, preferred because holes are made with standard drills and reamers
C.Transition fit — shaft always larger than hole, such as H7/p6 for a press fit and H7/s6 for a shrink fit that transmits torque without a key
D.Transition fit — tolerance zones overlap so the assembly may be slightly tight or loose, such as H7/k6 for locating gears and pulleys that also carry a key
A.Interference fit — shaft always larger than hole, such as H7/p6 for a press fit and H7/s6 for a shrink fit that transmits torque without a key
B.Interference fit — hole kept at H (zero lower deviation) and the fit obtained by varying the shaft, preferred because holes are made with standard drills and reamers
C.Interference fit — tolerance zones overlap so the assembly may be slightly tight or loose, such as H7/k6 for locating gears and pulleys that also carry a key
D.Interference fit — GO gauge checks all dimensions together as a full-form envelope at MMC, while NO-GO checks each dimension separately at LMC
A.shaft always larger than hole, such as H7/p6 for a press fit and H7/s6 for a shrink fit that transmits torque without a key
B.arithmetic mean deviation of the profile from its mean line, typically 0.8 µm for ground bearing seats, 1.6 for fine turning and 3.2 for general machining
C.tolerance grade IT01 to IT18 fixing the width of the zone, with IT5–IT7 for fits, IT8–IT11 for general machining and IT12 upward for raw processes
D.GO gauge checks all dimensions together as a full-form envelope at MMC, while NO-GO checks each dimension separately at LMC
20. Which term means: "arithmetic mean deviation of the profile from its mean line, typically 0.8 µm for ground bearing seats, 1.6 for fine turning and 3.2 for general machining"?
A.Surface roughness Ra — letter (uppercase for holes, lowercase for shafts) that fixes the position of the tolerance zone relative to the basic size
B.Surface roughness Ra — shaft always smaller than hole, such as H7/g6 for sliding spindles and H8/f7 for running bearings
C.Surface roughness Ra — arithmetic mean deviation of the profile from its mean line, typically 0.8 µm for ground bearing seats, 1.6 for fine turning and 3.2 for general machining
D.Surface roughness Ra — tolerance zones overlap so the assembly may be slightly tight or loose, such as H7/k6 for locating gears and pulleys that also carry a key
A.shaft always smaller than hole, such as H7/g6 for sliding spindles and H8/f7 for running bearings
B.GO gauge checks all dimensions together as a full-form envelope at MMC, while NO-GO checks each dimension separately at LMC
C.letter (uppercase for holes, lowercase for shafts) that fixes the position of the tolerance zone relative to the basic size
D.arithmetic mean deviation of the profile from its mean line, typically 0.8 µm for ground bearing seats, 1.6 for fine turning and 3.2 for general machining
A.Taylor's principle of gauging — GO gauge checks all dimensions together as a full-form envelope at MMC, while NO-GO checks each dimension separately at LMC
B.Taylor's principle of gauging — mean peak-to-valley height over five sampling lengths, about 4–7 times Ra and better at catching isolated scratches on sealing faces
C.Taylor's principle of gauging — hole kept at H (zero lower deviation) and the fit obtained by varying the shaft, preferred because holes are made with standard drills and reamers
D.Taylor's principle of gauging — tolerance zones overlap so the assembly may be slightly tight or loose, such as H7/k6 for locating gears and pulleys that also carry a key
A.arithmetic mean deviation of the profile from its mean line, typically 0.8 µm for ground bearing seats, 1.6 for fine turning and 3.2 for general machining
B.shaft always larger than hole, such as H7/p6 for a press fit and H7/s6 for a shrink fit that transmits torque without a key
C.GO gauge checks all dimensions together as a full-form envelope at MMC, while NO-GO checks each dimension separately at LMC
D.mean peak-to-valley height over five sampling lengths, about 4–7 times Ra and better at catching isolated scratches on sealing faces
26. Which term means: "mean peak-to-valley height over five sampling lengths, about 4–7 times Ra and better at catching isolated scratches on sealing faces"?
A.Rz roughness — mean peak-to-valley height over five sampling lengths, about 4–7 times Ra and better at catching isolated scratches on sealing faces
B.Rz roughness — shaft always smaller than hole, such as H7/g6 for sliding spindles and H8/f7 for running bearings
C.Rz roughness — tolerance zones overlap so the assembly may be slightly tight or loose, such as H7/k6 for locating gears and pulleys that also carry a key
D.Rz roughness — arithmetic mean deviation of the profile from its mean line, typically 0.8 µm for ground bearing seats, 1.6 for fine turning and 3.2 for general machining
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