dimensions and tolerances Flashcards
What is the purpose of a dimensioned drawing?
To provide all the measurements necessary for a finished product or part to be manufactured.
What are the rules for drawing dimensions?
Dimensions are always drawn using continuous thin lines.
Projection lines indicate where the dimension starts and finishes and do not touch the object.
What should dimensions less than 1 include?
A leading zero.
What is parallel dimensioning?
A method where several dimensions originate from one projection line.
What is superimposed running dimensioning?
A method that simplifies parallel dimensions to reduce space on a drawing.
What does a combined dimension use?
Both chain and parallel dimensioning.
What is chain dimensioning?
A method of dimensioning where dimensions are linked in a chain.
How are circles dimensioned according to approach (a)?
By projecting lines from two diametrically opposite points.
What does approach (b) involve for dimensioning circles?
Dimensioning the circle internally when it is too small for external dimensioning.
What prefix is used for all radial dimensions?
Capital R.
What does a tolerance value indicate?
The maximum permissible variation from the dimension.
How can tolerance values be specified?
As a general tolerance value or a specific tolerance for each dimension.
Fill in the blank: A tolerance value can appear as a general tolerance value applicable to several dimensions, for example, +/- ______ mm.
0.5
True or False: It is possible to manufacture products to the exact figures displayed on an engineering drawing.
False.
What is the significance of the dimensioning rules regarding projection lines?
They must be drawn at right angles to the element being dimensioned.
