Tolerances

It is necessary today to hold precise tolerances to insure the interchangeability of parts
Tolerances:
The process of determining how much a dimension can vary for a part to fit
How accurate is 1/4?
.25
.250
.2507 <---

Basic size  of a rim
Tolerance: Amont of dim varies from basic size.

Feature:
USed to indentify the geometry of the drawing being referred to
-hole
-cut
-extrusion

Limits: The maximum and minimun allowable size

Allowance: Limits where the smallest clearence or largest interference occuring in measurement at MMC

Tolerance style:
Limints dim: Anything in between is good
Plus+Minus Dim: Known as deviation
Symmetrica: Same as +/-
MMC:
Maximum Material Condition
The limit of a dim where the max is left on part
LMC:
Least Material Condition
Least amount of material is left on part

Type of fit:

Clearence:
All dims combinations will produce a clearence

Interferance:
Will create a force fit

Transitional:
Produce different kinds of fit

Auxiliary Notes

Secondary View:

TSS (True size and shape) of a surface that shows the forshorted in all traditional views.
***A Surface is TSS when it's egde in the next view is parrellel to the fold line.
*****SKIP A VIEW MEASURE BACK

Dimension Notes

Dimensions:
ANSI
American National Standards Instatute
They decide the standards for all drafting.
Why we dimension:
          Describe
          Locate details
The Big Three Dimensions:
-Width
-Depth
-Hieght

These are the first dimension always applyed while dimensioning a part.
Never apply two of the same dimensions on a drawing especially when you are dealing with three different views.
Always apply them in between views if possible ( Not always possible if dimensions get crowded).

The X, Y, Z
The normal axis points Y being Up/down, X being Side to Side,  and Z being Front to back.

Basic rules:
Make its convinient
No calculations necessary
No Double dimensions

Lines and Dimensions should be:
Lines and symbols inside lines if possible
If not put them outside

Extension:
1/16 in gap
No gap between extension line and center line

Leaders:
Leader scales = dim scale
Circles arch notes
Run at angle to show it's not part of the drawing
Short horizontal 1/4" tail
No Horizontal or Verticle angles
Not thru corners and short as possible

Linear Dims
H/W/D
In between views if possible
Where detail is best described
Don't dim hidden lines
Smallest dim are closest to part
No calculations
No double dims

Angle dims:
Same angle as object being drawn
Use degree symbol (##D)

Circuler dims:
Arc (less then full circle)
Circle use diameter
Arc us radius
Cylander in profile (Where it is best described)
Indicate finished surfaces.