SPROCKET - EXPLODED ASSEMBLY

SPROCKET - SECTIONED ASSEMBLY

SPROCKET - ISOMETRICS

SPROCKET - 2D VIEW PARTS

Descripitve Geometry

Manipulating picture planes in order to identify true size, true shape, true length, ture angle, intersection points, and distances

• True Length Lines
• if a line is parallel to a fold line in one view, it is true length in the next view
• Point View
• find a true length line
• create a fold line perpendicular to the true length line
• type "po" for point
• change "pdmode" to 96
• change "pdsize" to .1
• True Size and Shape (TSS) Surface
• first find true length of one line and point view of that line
• crate fold line perpendicular to the true length line to get the edge view of the surface
• crate fold line parallel to edge view
• Add-A-Line
• Draw a line parallel to F1 from 1 point to the line you want true length of
• Project the point where it hits the line you want true length of to the next view onthe same line
• connect that point to the point you started with which gives you a true length line
• create fold line perpendicular to true lenth which will give you your edge view including a point
• create fold line parallel to edge view which will give you your TSS surface

Auxiliary View Notes

Definition

• secondary view used to show true size and shape (TSS) of a surface that shows foreshortened in all traditional views

***A SURFACE IS TSS WHEN ITS EDGE IN THE NEXT VIEW IS PARALLEL TO THE FOLD LINE

*****SKIP VIEW, MEASURE BACK

Tolerance Notes

It is necessary today to hold precise tolerances to insure the interchangeability of parts
It's the process of determining the smount a dimension can vary from it's theorectical size

• Basic Size
• the exact theoretical size of a dimension
• Tolerance
• the amount a dimension can vary from basic size
• Feature
• used to identify the geometry of the drawing being referenced
• Limits
• the maximum and minimum allowable size
• Allowance
• the limits where the smallest clearance or largest interference occurs. Measured at MMC

Styles

• Limit Dimensioning
• Deviation Dimensioning
• Symmetrical Dimensioning

MMC

• (Maximum Material Condition)
• The limit of a dimension where the max material is left on the part

LMC

• (Least Material Condition)
• the limit of a dimension where the least amount of material is left on the part

Type of Fit

• Clearence (Running and Sliding Fit)
• all dimension combos will produce clearence between parts
• Interference
• all combos of dimensions will produce a force fit
• Transitional
• different combos of dimensions will produce different kinds of fits

Dimension Notes

ANSI - American National Standards Institute

• organization that established standards
• not arbitrary rules
• standard way of posistioning dimensions

Why?

• describes size
• locate details on an object

Rules

• Should be for the convience of person reading the drawing
• no calculations neceessary
• no duplications
• 1st dimension line should be 3/8" from object line
• no gap between line and center line
• leader scale should equal your dimension

Leaders

• arrow to edge
• dot to surface
• 1/4" tail
• cross as few lines as possible
• any angle except horizontal or verticle
• do not pass them through corners
• short as possible

Linear Dimensions

• ALWAYS HAVE HEIGHT, WIDTH, AND DEPTH
• dont't dimension from a hidden line if possible
• locate from a common corner
• smallest dimension closet to part

Angle Dimensions

• use degree symbol (%%D)
• drawn at same angle as object being dimensioned

Circle Dimensions

• ARC always dimensioned with radius
• CIRCLE always dimensioned with diameter (%%C)
• cylinder gets dimensioned in the side view
• hole gets dimensioned where it shows

Ordinate Dimensions

• use distances on the x and y coordinates
• relative from the origin (0,0)
• UCS - user coordinate system
• move UCS
• Type "UCS"
• Type "M"
• Click where you want the origin

Counterbore & Countersink

• Underline
• Type "%%U"
• Plus/Minus Sign
• Type "%%P"
• Counterbore
• bolt head or scre flush with surface
• Countersink
• bolt or screw flush with surface