dim notes

American National Standards Institute (ANSI)

• Establishes the dim standards
• Rules Don't change
• Makes the rules for dim positioning

Why use dims

• discribe the size of an object
• locate details on an object

Basic Rules

• Should be convienent for readers
• no calculations necessary
• no duplications of dims
• first dim line should not be closer than 3/8'' from object
• lines/symbols inside extension lines, if not possible text inside,lines out,if not all outside
• extension lines give a 1/16'' gap between them and object

Leaders

• leader scale = dim scale
• run at angle
• arrow = edge, dot = surface
• cross as few lines as possible
• don't pass through corners

Linear dims

• first 3 big dims: height, width, depth
• between views
• come from view where detail is best shown
• dont dim to hidden lines
• locate from common corner
• smallest dim = closest to object

Angle dim

• drawn at same angle as dim
• use degree symbol: make by typing %%d after text

Circular dims

• Arc = dim as radius
• circle dim as diameter
• cylender dim in side view
• hole dim were its shown with leader

Finished surface

• use a check mark 1/4'' tall

Ordonate dims

• uses distances on X and Y cordonates
• UCS- user cordonate sysyem
• typ: ucs, press enter,move,enter,then pic new origin

Counterbore/ Countersinks

• c'bore is used when a bolt or caphead needs to be flush with a surface, Drill hole is the small hole, c'bore hole is the big hole, in cad type c'bore before diameter of c'bore hole and after type diameter of hole through

Symbols

• Counter bore = a squaired off u
• Deep = an downward facing arrow with horozontile line on top
• Counter sink = V

• c'sinks allows screw head to sit flush
• c'sink anlgle is 82 degrees