Engineering graphics ch 11 and 13

What are the 3 aspects of good dimensioning

Technique of dimensioning, placement of dimensions, and choice of dimensions

Technique of dimensioning

Standards for the appearance of lines, spacing of dimensions, size of arrowheads

Placement of dimensions

Use logical placement for the dimensions according to standard practice so that they are legible

Choice of dimensions

Give dimensions that are necessary for producing the part where none must be assumed

Tolerance

The toal amount that the feature on the actual part is allowed

Which dimensioning methods permit the accumulation of tolerance?

Chain dimensioning

Centerlines may not be used as extension lines

False

The symbol for counterbore is a V with legs 90 degrees apart

False

When a dimension is enclosed in parentheses, it dictates

Reference dimensions

What type of line is a thin, dark and has arrowheads on each end

Dimension line

What is the minimum distance between parallel dimensions

1/4” or 6mm

Arcs are usually dimensioned using____.

Radius

Crossing extension lines is an acceptable practice

False

Crossing dimension lines should be avoided

True

Leaders should never be drawn in which directions

Horizontal or vertical and parallel to nearby lines of the drawing

Know definitions from the thread form

Root, crest, Pitch diameter, thread angle, side, minor diameter, major diameter, lead

Who standardized screw thread in 1841

Sir Joseph Whiteworth

The diameter of an imaginary cylinder passing through the threads to make equal the widths of the threads and the widths of the spaces cut by the cylinder is called

pitch diameter

Which line type may be used to show a repetition of series of identical features?

Phantom line

In the thread designation, .25-20 UNC-2B LH, what is the meaning of "UNC"? 

Unified course

In the thread designation, .25-20 UNC-2B LH, what is the meaning of "20"? 

Thread per inch

Which screw heads allow flush placement with the surface of the material? 

Flat head

What type of screw is screwed through one member and is forced against another member.  

Set screw

A key is used to prevent relative movement between a shaft and wheel

True

What is a jam nut?

thinner than the standard nut and is frequently used to lock regular nuts in place 

What are the 3 types of compression springs?

conical coil and helical

the 3 basic application of screw threads are

1. To hold parts together 
2. For fine adjustment between parts with reference to each other 
3. For fine measurement