Computer Aided Design (CAD) Engineering Drawing Standards - BS308

Orthographic Projection

SOME TECHNICAL TERMS (page 1) Flange Keyway Key Taper Shaft Shoulder BushWeb Bore Boss CollarSpoke Rim Hub Pulley Rib Bracket base Fillet Table Slot Spotface Counterbore Lug Countersink Dowel Blind hole Tee slot Chamfer Spigot Recess

SOME TECHNICAL TERMS (page 1) CAN YOU DETERMINE THE PROJECTION SYSTEM USED? (first or third angle?) CAN YOU IDENTIFY THE TYPES OF HOLES ABOVE?

Projection Symbol – How to Draw

COMMON LINE TYPES (page 5) 1. Continuous Thick (0.5mm) TYPE A 2. Continuous Thin (0.25mm) TYPE B 3. Dashed Thin (0.25mm) TYPE E 4. Chain Thin (0.25mm) TYPE F

LINETYPES Hidden Center Hatch Outlines Text Dimension Lines Leader Lines

To show where dimensions or notes apply. Always end in arrowheads or dots. Arrowheads touch and stop on a line Dots should be within the outline of the object. Long or intersecting leader lines should not be used.

General Points on Drafting Arrows: Triangular and Solid Length = 3 x width Arrows on Dimensions -> 3-5mm Long Arrows showing direction of view -> 7-10mm Long Text Height = Not less than 3mm. Underlining of text is not recommended. Notes of a general character to be grouped together.

General Points on Drafting

Commonly Accepted Symbols and Abbreviations AF ASSY CRS CL CHAM CH HD CSK CSK HD CBORE CYL DIA DRG EQUI SP EXT FIG. HEX HYD INSUL INT LH LG MATL MAX MIN

Commonly Accepted Symbols and Abbreviations NO. O/D PATT NO. PCD RAD R REQD RH RD HD SCR SH SK SPEC SR SFACE SQ STD THD TYP UCUT VOL WT

SCREW THREAD - TERMS

SCREW THREAD - TYPES

SCREW THREAD - External NOTE: Inner lines are Type 2 Lines (Continous Thin Lines)

SCREW THREAD - Internal NOTE: Inner lines are Type 2 Lines (Continous Thin Lines)

SCREW THREAD - Internal

SECTIONS AND SECTIONAL VIEWS (page 12 BS308) Hatching is Drawn with Type B (Continuous Thin) Lines, equally spaced at 45º. Preferably not less than 4mm Apart With very small parts, never less than 1mm On adjacent parts, alternate the direction of Hatching. Correct Section Line – Type F (Chain Thin)

SECTIONS AND SECTIONAL VIEWS

(page 15 BS308) PARTS NOT NORMALLY SECTIONED WHEN THE CUTTING PLANE PASSES LONGITUDINALLY THROUGH: FASTNERS (bolts, nuts) SHAFTS, RIBS, WEBS, SPOKES of WHEELS etc.

SECTIONS AND SECTIONAL VIEWS (page 15 BS308) FASTNERS AND SHAFT NOT SECTIONED WEB NOT SECTONED

OFFSET SECTION SECTION IN MORE THAN 1 PLANE

EXTRA RESOURCE INFORMATION DeGarmo, E. P., et al., Materials and Processes in Manufacturing, 8th Ed., Maxwell Macmillan, 1997