7/31/2019 RTC Drawing Guidelines
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7/31/2019 RTC Drawing Guidelines
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7/31/2019 RTC Drawing Guidelines
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DimensionsLocation
Locate dimension lines and text outside the object outline
Dimension lines to be in. (6mm) from the outline, other dimension lines .15 in. (4mm) apart
Place dimensions between the views if possible
Cylindrical diameters should be shown on the rectangular view, preceded by a diameter symbol
Show enough dimensions to avoid calculating or assuming any distances
Place each dimension so that it has only one interpretation
Dimension the most descriptive view, where the profile or true shape appears
Dimension from visible lines, not from hidden lines
Do not repeat dimensions
Stagger or move dimension text if necessary to prevent crowding
Dimension lines should not cross other lines. If unavoidable, break the dimension lines
Apply dimensions so that accumulation of tolerances is minimized
Format
Dimension and leader arrows to be .12 in. (2.5mm) long, solid filled Dimension text to be horizontal, centered between the arrows where possible
If moved away from the dimension line, linear dimension text should not have a leader
Dimension rounded corners and fillets to the theoretical intersection
Show hole sizes in their circular views with a diameter dimension or a hole note
Holes, diameters and arcs should have centre marks and centre lines
Dimension arcs with a radial dimension
Fillets and corner radii can be dimensioned by a leader note, preceded by R
Inch dimensions should have no leading zero
Metric dimensions should have no trailing zero, except for the number 1.0
Tolerances should all use the same number of digits, except for unilateral 0 in metric
Threads and Fasteners
Use simplified format external threads show a continuousthick line for the crest and thin line for the root, internalthreads show a thin hidden line for the crest and root
Sectioned threads use a thick continuous line for the crestand thin line for the root diameters
End view of a thread shows a thick circle for the crest and
a thin 270 circle for the root
Threads should be specified using standard specification
External threads should show a chamfer at the end
Internal threads should show the thread depth and holedepth in hidden and section views
Show standard fasteners only on assembly drawings, withthe type and size correctly specified
Do not section standard fasteners on either full or sectionedassembly drawings