Student Guide to Preparing and Reviewing Engineering DrawingsPurpose of Document: This document has been created to aid students in preparing and reviewing engineering drawings. I. Formata. All drawings must have a border. Standard borders included with most CAD systems are recommended.b. All drawings must have a title block that includes the following elements. i. Descriptive part name.ii. Company name or Grand Valley State University.iii. Name of the person who created the drawing.iv. Date the drawing was created.v. Name of the person who reviewed the print. All prints must be reviewed before submission.vi. Indication of units used.vii. Unless otherwise specified tolerances.II. Orthographic Viewsa. Enough views must be included to completely describe the part.b. The most descriptive view should be chosen as the front view. For most parts this choice will minimize the number of hidden lines required.c. The views must be positioned and aligned correctly.d. Holes and arcs with an included angle of greater than 180 degrees must have center marks and centerlines in appropriate views.e. Blind holes formed by drilling must have drill points shown unless the design requires otherwise.f. Features that make the part easier to manufacture or assemble must be incorporated into the part.III. Dimensioning a. Dimensions must specify the size and location of each feature. For example a size dimension and two linear position dimensions are usually required to completely describe the feature.b. Dimensions that determine whether the part assembles or operates correctly must be called out directly and therefore avoid requiring the reader to add or subtract dimensions. This can minimize tolerance stack up problems.c. Holes that form a pattern must be dimensioned relative to each other and then one hole in the pattern must be located relative to another significant feature.d. No dimensions should appear on a view of the part.e. Smaller dimensions must be placed closer to the views than larger dimensions.f. Chained dimensions must be aligned.g. A hole’s size and location should be dimensioned in the profile view.Page 1 of 2h. If a full circle or an arc of more than half is a circle is being dimensioned then the diameter is specified, preceded by the diameter symbol. If the arcis less than a half circle, the radius is specified, preceded by an R. (pg. 491Bertoline and Wiebe) i. Similar features should be dimensioned in identical ways.IV. Tolerancinga. Tolerances must be consistent with the capabilities of the intended manufacturing process.b. Tolerances must be chosen to ensure that the parts assemble and operate correctly when the parts are at the upper or lower limit of their tolerance range.c. If the minimum clearance between mating parts, the allowance, is zero theparts may not assemble easily. Remember a half-inch peg will not fit in a half-inch hole without force.d. Dimensions that determine whether the part assembles or operates correctly should have smaller tolerances than dimensions to non-contacting surfaces. e. Use of “unless otherwise specified” or default tolerances is encouraged to decrease the clutter of a drawing but all dimensions should not have the same tolerance.Page 2 of
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