Tolerancing

Part 1

Interpreting, Specifying,Manufacturing & Measuring

Various Dimensional Tolerances

Specification For

Paper Sizes

Paper Sizes

Series of Sizes:

• Based on Width : Length = 1 :

•Each next smaller size has an area = Half that of previous bigger size

•Next smaller size produced by halving the longer dim(retaining the shorter dim as the new length)

Paper Sizes

A0 = 841 X 1189 = 1.0000 m2

A1 = 594 X 841 = 0.5000 m2

A2 = 420 X 594 = 0.2500 m2

A3 = 297 X 420 = 0.1250 m2

A4 = 210 X 297 = 0.0625 m2

Tolerancing

Tolerance = Permissible Variation

To be specified only when & where essential for functionality

Tolerancing

Cost of

Mfg

Tolerance

Costly Zone Optimum Zone

Tolerancing

Tolerance

Dimensional

• Dia

• Length

Tolerancing

Tolerance

Dimensional Form

• Circular

• Straightness

• Cylindricity

Variation of actual condition of form feature(Surface/line) from geometrically ideal position

Tolerancing

Tolerance

Dimensional Form Positional

B

A

Tolerancing

Tolerance

Dimensional Form Positional Surface Finish

Tolerancing

Tolerance

Dimensional Form Positional Surface Finish

Tolerance of Size automatically limits the tolerance of form & position!

The indication of tolerance of form & position does not necessarily imply the use of any particular method of mfg..

Tolerancing

Tolerance

Dimensional Form Positional Surface Finish

Waviness

Tolerancing

General Tolerances = ?

Tolerancing

General Tolerances =

Tolerances for

Linear & Angular dimensions

without individual Tolerance Indications

Ref IS 2102(Part 1) : 1993

ISO 2768-1 : 1989

Tolerance on dims. Unless otherwise specified

CategoryClass

0.5 to 3mm

3 to 6 mm 6 to 30mm30 to

120mm

Fine ?

Medium

Coarse

ExtraCoarse

Tolerancing

Tolerancing

Examples for

• Fine

• Medium

• Coarse

• Extra Coarse Components ?

Tolerancing

“One thing at a time & that too done well is the way to happiness” AKB

Tolerancing

Examples for

• Fine : Rollers for Needle bearings

• Medium :

• Coarse :

• Extra Coarse :

Tolerancing

Examples for

• Fine : Rollers for Needle bearings

• Medium : Swiss Auto -Turned Parts

• Coarse :

• Extra Coarse :

Tolerancing

Examples for

• Fine : Rollers for Needle bearings

• Medium : Swiss Auto -Turned Parts

• Coarse : Rivet

• Extra Coarse :

Tolerancing

Examples for

• Fine : Rollers for Needle bearings

• Medium : Swiss Auto -Turned Parts

• Coarse : Rivet

• Extra Coarse : Forged part

Tolerancing

Examples for

• Fine : Rollers for Needle bearings

• Medium : Swiss Auto -Turned Parts

• Coarse : Rivet

• Extra Coarse : Forged part

Note: Hybrid Tolerancing not allowed!

Tolerancing

Tolerance on dims. Unless otherwise specified

CategoryClass

0.5 to 3mm

3 to 6 mm 6 to 30mm30 to

120mm

Fine +/-0.05

Medium ?

Coarse

ExtraCoarse

Tolerancing

Tolerance on dims. Unless otherwise specified

CategoryClass

0.5 to 3mm

3 to 6 mm 6 to 30mm30 to

120mm

Fine +/-0.05

Medium +/-0.10

Coarse ?

ExtraCoarse

Tolerancing

Tolerance on dims. Unless otherwise specified

CategoryClass

0.5 to 3mm

3 to 6 mm 6 to 30mm30 to

120mm

Fine +/-0.05

Medium +/-0.10

Coarse +/-0.30

ExtraCoarse

?

Tolerancing

Tolerance on dims. Unless otherwise specified

CategoryClass

0.5 to 3mm

3 to 6 mm 6 to 30mm30 to

120mm

Fine +/-0.05

Medium +/-0.10

Coarse +/-0.30

ExtraCoarse

+/-0.50

Tolerancing

Tolerance on dims. Unless otherwise specified

CategoryClass

0.5 to 3mm

3 to 6 mm 6 to 30mm30 to

120mm

Fine +/-0.05 +/-0.05 +/-0.15 +/-0.2

Medium +/-0.10 +/-0.10 +/-0.20 +/-0.30

Coarse +/-0.20 +/-0.30 +/-0.50 +/-0.80

ExtraCoarse

NA +/-0.50 +/-1.00 +/-1.50

Tolerancing

Exclusive For Tool Drawings:

20,0 = 20+/-0.5

Tolerancing

Exclusive For Tool Drawings:

20,0 = 20+/-0.5

20,00 = 20+/-0.05

Tolerancing

Exclusive For Tool Drawings:

20,0 = 20+/-0.5

20,00 = 20+/-0.05

20,000 = 20+/-0.005

Tolerancing

Company Standards for general Tolerances

IS 2102 for ‘Rubber Parts’ Anecdote

Tolerancing

“Loose Tolerances tightly held are better than tight tolerances loosely held”

Centurion

Tolerancing

ASSEMBLY

Interchangeable Assembly

Graded Assembly

Selective Assembly

? ? ?

Tolerancing

Tolerance

Min Bore Max Bore

BORE FEATURES

Tolerancing

Tolerance

Min Bore Max Bore

BORE FEATURES

Dist. Between axes = ?

Tolerancing

Combined Representation of Bore

Min?

Max?

Tol?

Tolerancing

Tolerance

Max Shaft

Min Shaft

SHAFT FEATURES

Tolerancing

Tolerance

Max Shaft

Min Shaft

Combined

Representation

SHAFT FEATURES

Tolerancing

Basic Size of Bore

Basic Size of Shaft

Tolerancing

Line of zero deviation

Basic Size

Lower Deviation

Upper Deviation

BORE FEATURES

Tolerancing

Line of zero deviation

Lower Deviation

Upper Deviation

Basic Size

SHAFT FEATURES

Tolerancing

Line of zero deviation

Lower Deviation

Lower Deviation

Upper Deviation

BORE & SHAFT FEATURES

Upper Deviation

Basic Size

Tolerancing

Feature Deviation

Bore Shaf t

Upper Max MaxLower Min Min From Basic Size

Tolerancing

Feature Deviation

Bore Shaf t

Upper ES esLower EI ei* From Basic Size

Tolerancing

FEATUREDEVIATION *

BORE SHAFT

UPPERLOWER

* FROM BASIC SIZE

Tolerancing

Line of zero deviation

EI

ei

es

BORE & SHAFT FEATURES

ES

Basic Size

Does Tolerance have a sign?

Answer in Part 2

Tolerancing