This presentation would help you in understanding Limits, Fits & Tolerances used in various engineering designs and drawings.

9. 5 Types Types Form Straightness Flatness Circularity Cylindricity Profile Profile of a Line Profile of a Surface Position Orientation Location Angularity Perpendicularity Parallelism True Position Concentricity Symmetry Run Out Circular Run - Out Total Run - out

11. Notations Reference Datum Datum Symbol Axis as Datum Surface Line as Datum Toleranced Element/Parameter 0.02 A Tolerance Symbol Tolerance Symbol Datum ( When required) A 25 Nominal Dimension

12. Feature Control Frame Position Tolerance Zone Symbol Shape of Tolerance Zone Size of Tolerance Zone Primary Datum Secondary Datum Tertiary Datum Material Condition Modifier Secondary Datum Material Condition Modifier B A 0.2 M C M

13. Function drives Modifiers Modifiers E=mC 2 E=cM 2

16. Process Control Size Boss Vs Hole LMC 25 +2 B A 1 C L B A 0.2 C L LMC – Boss & Hole C B 12 - 0.5 A 75 60 25 12 Boss Tol. Zone 1 Hole Tol. Zone 0.2

18. Classic Case- Bell Crank & Sleeve Modifiers at MMC A A 0.02 M 25 0.00/-0.018 18 0.00 /-0.013 A A 0.02 M 25 0 .02/0.00 18 0.013/0.00

19. Modifiers MMC On Hole M Datum A 0.2 M Hole 60 10 +0.2 / 0 20 +0.1 / 0 A 0.4

20. Modifiers at MMC On Datum M Datum Hole A 0.2 M 60 10 +0.2 / 0 20 +0.1 / 0 A 0.3

21. Modifiers MMC On Hole & Datum M Datum 0.2 M Hole 60 10 +0.2 / 0 20 +0.1 / 0 A A M 0.6

23. Manufacturing & Inspection w.r.t.specified datum Datum External Datum Datum Simulator Datum Simulator Datum Simulator Internal Datum A A A

26. Neck Bow Barrel STRAIGHTNESS 0.21

27. Cylinder Liner Tier 2 STRAIGHTNESS 0.21

29. Direction is in the View Straightness: Applied to a plane surface Measurement Direction STRAIGHTNESS 0.21

30. Combined Straightness “is” Flatness The tol. notation is attached to a leader line to the surface or to an extension line of the surface. STRAIGHTNESS 0.21

31. Controls Form deviation of plane surfaces – Qualifies surface for primary datum FLATNESS DEFINITION Flatness is the condition of a surface having all the elements of which in one plane. TOLERANCE ZONE The flatness tolerance specifies a tolerance zone defined by two parallel planes within which the surface must lie. REFERENCE TO DATUMS No reference datum. MMC, LMC, RFS TO FEATURE Not applicable. MMC, LMC, RFS TO DATUMS Not applicable.No reference datum PERFECT FORM AT MMC Where the surface under consideration has a size dimension, the flatness tolerance must be less than the size tolerance. Flatness 0.05 0.05/100

33. Flatness – Primary Datum/Seat/Sealing face Flatness 0.05

34. Datum , Seat Definition Flatness 0.05

35. Defines Datum DEFINITION Circularity is a condition of a surface of revolution where a. (For a Cylindrical/Round feature other than a sphere,) all points of the surface intersected by any plane perpendicular to the axis are equidistant from that axis; b. For a sphere, all points of the surface intersected by any plane passing through a common center are equidistant from that center. TOLERANCE ZONE A circularity tolerance specifies a tolerance zone bounded by two concentric circles within which each circular element of the surface must lie, and applies independently at any plane. REFERENCE TO DATUMS No reference datum. MMC, LMC, RFS TO FEATURE Not applicable. MMC, LMC, RFS TO DATUMS Not applicable.No reference datum PERFECT FORM AT MMC The circularity tolerance must be less than the size tolerance, except for parts subject to free state variation. CIRCULARITY/ROUNDNESS 0.05

36. The tolerance zone of circularity is expressed as the radial difference between two concentric circles The circularity tolerance applies at each circular section of the diameter independently CIRCULARITY/ROUNDNESS 0.05

37. CIRCULARITY/ROUNDNESS 0.05

38. “ Combined effect” of Straightness & Roundness DEFINITION Cylindricity is a condition of a surface of revolution in which all points of the surface are equidistant from a common axis. TOLERANCE ZONE A Cylindricity tolerance specifies a tolerance zone bounded by two concentric cylinders within which the surface must lie. REFERENCE TO DATUMS No reference datum. MMC, LMC, RFS TO FEATURE Not applicable. MMC, LMC, RFS TO DATUMS Not applicable.No reference datum PERFECT FORM AT MMC Applicable. Cylindricity tolerances cannot violate the maximum boundary of perfect form at MMC of the associated size tolerance. Application Functional applications that require a true cylinder such as rotating shaft journal and bearing diameters, pistons and piston bores. Also used to qualify datum diameters. Used only when the size tolerance does not provide appropriate form control. Cylindricity 0.03

40. Cylindricity 0.03

41. DEFINITION A profile is the outline of an object in a given plane. The profile tolerance specifies a uniform boundary along the true profile within which the elements of the line must lie. It is used to control form or combinations of size, form, orientation, and location. TOLERANCE ZONE The tolerance zone established by the profile of a line tolerance is two-dimensional, extending along the length of the considered feature. This applies to the profiles of parts having a varying cross section, such as the tapered wing of an aircraft, or to random cross sections of parts where it is not desired to control the entire surface of the feature as a single entity. REFERENCE TO DATUMS In most cases, profile of line tolerance requires reference to datum in order to provide proper orientation, location, or both, of the profile. With profile of a line tolerance, datum may be used under some circumstances but would not be used when the only requirement is the profile shape taken cross section by cross section. An example is the shape of a continuous extrusion. MMC, LMC, RFS TO FEATURE The specified tolerance can only apply on an RFS basis. MMC, LMC, RFS TO DATUMS The datum reference can only apply on an RFS basis. Application Typically used to control profiles of parts having a varying cross section. Line Profile 0.1 0.1 A

43. DEFINITION A profile is the outline of an object in a given plane. The profile tolerance specifies a uniform boundary along the true profile within witch the elements of the line must lie. It is used to control form or combinations of size, form, orientation, and location. TOLERANCE ZONE The tolerance zone established by the profile of a surface tolerance is three-dimensional, extending along the length and width (or circumference) of the considered feature or features. REFERENCE TO DATUMS Profile of surface tolerance requires reference to datum in order to provide proper orientation, location, or both, of the profile. With profile of a line tolerance, datum may be used in some circumstances but would not be used when the only requirement is the profile shape. MMC, LMC, RFS TO FEATURE The specified tolerance can only apply on an RFS basis. MMC, LMC, RFS TO DATUMS The datum reference can only apply on an RFS basis. TYPICAL USE Typically used to control parts with a surface of revolution, or castings with surfaces defined by profile tolerances . Surface Profile 0.05 A 0.05

45. Gen 1 Bell Crank Surface Profile 0.05

47. Position Tolerance

49. ZERO POSITIONAL TOLERANCE AT MMC Where no variations in position is allowed at the MMC limit of size, the feature control frame contains a zero for the tolerance zone size, modified by the MMC symbol. PATTERN-LOCATING TOLERANCE ZONE FRAMEWORK (PLTZF) Where composite controls are used, the upper segment is referred to as the pattern-locating control. The PLTZF is located from specified datum by basic dimensions. It specifies the larger positional tolerance for the location of the pattern of features as a group. FEATURE-RELATING TOLERANCE ZONE FRAMEWORK (FRTZF) The lower segment is referred to as the features-locating control. It governs the smaller positional tolerance for each feature within the pattern (feature-to-feature relationship). Where datum references are not specified in the lower segment of the composite feature control frame, the FRTZF is free to bee located and oriented within the boundaries established and governed by the PLTZF. If datum are specified in the lower segment, they govern the orientation of the FRTZF relative to the PLTZF. TYPICAL USE Typically used to control the location of features in assembly. B A 0.2 C M B A 0.2 C M B A 0.2 C M M 0.2 M Hole Position 0.2

50. The PLTZF (Ø0.8) is located from datum (ABC) by basic dimensions. It specifies the larger positional tolerance for the location of the pattern of holes as a group. The lower segment governs the smaller positional tolerance (Ø0.25) (feature-to-feature relationship) within the pattern . The FRTZF is free to locate and orient within the boundaries established and governed by the PLTZF. Datum A governs the orientation (perpendicularity) of the FRTZF . Pattern Location - PLTZF Feature Realtion - FRTZF Hole Position 0.2

51. Co- Axial Holes Pattern Location - PLTZF Feature Relation Location - FRTZF Hole Position 0.2

53. Hole Position 0.2

54. DEFINITION The median points of all diametrically opposed elements of a surface of revolution lie on the same axis (or center point) of a datum feature. TOLERANCE ZONE A concentricity tolerance is a Cylindrical (or spherical) tolerance zone whose axis (or center point) coincides with the axis (or center point) of the datum feature(s). REFERENCE TO DATUMS One datum feature (axis or center point). APPLICABILITY OF MMC, LMC, RFS TO FEATURE The specified tolerance can only apply on an RFS basis. APPLICABILITY OF MMC, LMC, RFS TO DATUMS The datum reference can only apply on an RFS basis. TYPICAL USE Typically used to control ……….. Concentricity 0.04 A

56. Use Either as Datum Position Tolerance Concentricity

57. Use a Spigot Locator Position Tolerance Concentricity

58. DEFINITION The median points of all opposed or correspondingly-located elements of two or more feature surface lie in the same axis or center plane of a datum feature. TOLERANCE ZONE A symmetry tolerance is two parallel planes whose axis (or center plane) coincides with the axis (or center plane) of the datum feature. REFERENCE TO DATUMS One datum feature (center plane). APPLICABILITY OF MMC, LMC, RFS TO FEATURE The specified tolerance can only apply on an RFS basis. APPLICABILITY OF MMC, LMC, RFS TO DATUMS The datum reference can only apply on an RFS basis. Symmetry 0.05 A

60. Gen1 Bell Crank Symmetry 0.05 A

61. Position Tolerance Angularity DEFINITION Condition of a surface, center plane, or axis at a specified angle from a datum plane or axis. TOLERANCE ZONE A angularity tolerance specifies one of the following: 1. A tolerance zone defined by two parallel planes at the specified basic angle from one or more datum planes or axis, within which the surface or center plane of the considered feature must lie. 2. A tolerance zone defined by two parallel planes at the specified basic angle from one or more datum planes or axis, within which the axis ot the considered feature must lie. 3. A cylindrical tolerance zone at the specified basic angle from one or more datum planes or axis, within which the axis of the considered feature must lie. 4. A tolerance zone defined by two parallel lines at the specified basic angle from one or more datum planes or axis, within which the line element of the surface must lie. REFERENCE TO DATUMS One or more datum features. Relation to more than one datum feature is specified to stabilize the tolerance zone in more then one direction. MMC, LMC, RFS TO FEATURE Based on functional requirements MMC, LMC or RFS, appropriate modifier can be applied on angularity tolerance. Application of MMC, LMC and RFS is limited to features subject to variations in size. MMC, LMC, RFS TO DATUMS If the functional requirements of some applications require MMC, LMC or RFS, appropriate modifier can be applied on the datum axis. Application of MMC, LMC and RFS is limited to features subject to variations in size. PERFECT ANGULARITY AT MMC Where no variations of angularity at MMC size limit of feature, the feature control frame contains a zero for the tolerance, modified by the symbol for MMC. TYPICAL USE Typically used to control orientation between planes surfaces.

64. Position Tolerance Perpendicularity DEFINITION Condition of a surface, center plane, or axis at a right angle to a datum plane or axis. TOLERANCE ZONE 1. A tolerance zone defined by tow parallel planes perpendicular to a datum plane or axis, within which the surface or center plane of the considered feature must lie. 2. A tolerance zone defined by two parallel planes perpendicular to a datum axis, within which the axis ot the considered feature must lie. 3. A cylindrical tolerance zone perpendicular to a datum plane, within which the axis of the considered feature must lie. 4. A tolerance zone defined by two parallel lines perpendicular to a datum plane or axis, within which the line element of the surface must lie. REFERENCE TO DATUMS One or more datum features. Relation to more than one datum feature is specified to stabilize the tolerance zone in more then one direction. MMC, LMC, RFS TO FEATURE Based on the functional requirement MMC, LMC or RFS, appropriate modifier can be applied on perpendicularity tolerance. Application of MMC, LMC and RFS is limited to features subject to variations in size. MMC, LMC, RFS TO DATUMS Based on functional requirements MMC, LMC or RFS, appropriate modifier can be applied on the datum axis. Application of MMC, LMC and RFS is limited to features subject to variations in size.. PERFECT PEPENDICULARITY AT MMC Where no variations of perpendicularity at MMC size limit of feature, the feature control frame contains a zero for the tolerance, modified by the symbol for MMC.

68. 100

69. Position Tolerance Parallelism DEFINITION Condition of a surface, center plane, equidistant at all points from a datum plane; or axis and equidistant along its length from one or more datum planes or a datum axis. TOLERANCE ZONE A parallelism tolerance specifies one of the following: 1. A tolerance zone defined by tow parallel planes parallel to a datum plane or axis, within which the surface or center plane of the considered feature must lie. 2. A tolerance zone defined by two parallel planes parallel to a datum axis, within which the axis ot the considered feature must lie. 3. A cylindrical tolerance zone parallel to a datum plane, within which the axis of the considered feature must lie. 4. A tolerance zone defined by two parallel lines parallel to a datum plane or axis, within which the line element of the surface must lie. REFERENCE TO DATUMS One or more datum features. Relation to more than one datum feature is specified to stabilize the tolerance zone in more then one direction. MMC, LMC, RFS TO FEATURE Based on functional requirements MMC, LMC or RFS, appropriate modifier can be applied on parallelism tolerance. Application of MMC, LMC and RFS is limited to features subject to variations in size. MMC, LMC, RFS TO DATUMS Based on functional requirements MMC, LMC or RFS, appropriate modifier can be applied on the datum axis. Application of MMC, LMC and RFS is limited to features subject to variations in size.. PERFECT PARALLELISM AT MMC Where no variations of parallelism at MMC size limit of feature, the feature control frame contains a zero for the tolerance, modified by the symbol for MMC.

71. Position Tolerance Parallelism

73. Position Tolerance Run-out DEFINITION Runout is a composite tolerance used to control the functional relationship of one or more features of a part to a datum axis. The types of features controlled by runout tolerance include those surfaces constructed around a datum axis and those constructed at right angles to a datum axis. TOLERANCE ZONE Each considered feature must be within its runout tolerance when the part is rotated about the datum axis. The tolerance specified for a controlled surface is the total tolerance or full indicator movement (FIM). REFERENCE TO DATUMS One or more datum features. Relation to more than one datum feature is specified to stabilize the tolerance zone in more then one direction. APPLICABILITY OF MMC, LMC, RFS TO FEATURE The specified tolerance can only apply on an RFS basis. APPLICABILITY OF MMC, LMC, RFS TO DATUMS The specified datum can only apply on an RFS basis. TYPICAL USE Typically used to control circularity and concentricity simultaneously.

74. Position Tolerance Run-out Run-Out: Circular / Radial Run- Out At any measuring position, each circular element of these surfaces must be within the specified run-out tolerance (0.02 mm FIM) when the part is rotated 360º about the datum axis with the indicator fixed in a position normal to the true geometric shape.

75. Run-Out: (Circular / Radial) Total Indicated Reading The entire surface must lie with the specified total run-out tolerance zone (0.02 mm FIM) When the part is rotated 360º about the datum axis with the indicator placed at every location along the surface in a position normal to the true geometric shape without reset of the indicator

76. Run-Out: (Circular / Radial) Total Indicated Reading

77. Run-Out: Face- Total Indicated Reading- Example

79. Building Blocks

80. Template Types M Straightness Flatness Circularity Cylindricity Profile of a Line Profile of a Surface Angularity Perpendicularity Parallelism Concentricity True Position Symmetry Circular Run - Out Total Run - out 25 +2 B A 1 C L B A 0.2 C L