Machine Drawing

Limits, Tolerances and Fits 237

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d:\N-Design\Des15-2.pm5

9. Symmetry tolerance

A 0.08A

.04

10. Radial run-out

0.1D

D

Permissible cross

indicator runout

(Between centres) 0.1

11. Axial run-out

0.1D

D

Permissible longitudinal

indicator runout (Between

centres) 0.1

THEORY QUESTIONS

15.1 Define the terms: (a) basic size, (b) limits, (c) allowance, (d) tolerance and (e) deviation.

15.2 What is an unilateral tolerance and what is a bilateral tolerance?

15.3 What is fundamental tolerance and how tolerance is denoted?

15.4 What are the different methods used for placing limit dimensions?

15.5 What is meant by the term “fit” and how are fits classified?

15.6 Differentiate between clearance fit and transition fit.

15.7 Name the two systems that are in use for finding out limit dimensions.

15.8 Differentiate between hole basis system and shaft basis system.

15.9 When is a shaft basis system preferred to hole basis system?

15.10 What is meant by tolerance of (a) form and (b) position?

15.11 Explain the term tolerance zone with reference to the tolerance of form and position.

15.12 Define the following terms:

(a) datum, (b) datum feature, (c) datum triangle and (d) datum letter.

15.13 With the help of a sketch, show how geometrical tolerances are indicated on a drawing.

15.14 With the help of a sketch, show how the tolerance frame is connected to the feature controlled.

15.15 What are the various ways by which a tolerance frame is connected to the tolerance feature?

Explain with the help of sketches.

15.16 With the help of sketches, show how the geometrical tolerances are indicated, as prevalent in

industry, for the following cases:

(a) parallelism, (b) perpendicularity, (c) symmetry and (d) radial run out.