Notation on an engineering drawing or schematic that instructs how a part is made or a system assembled.
A truncated cone shown in two views, stating which projection convention a drawing uses.
A truncated cone in two views, mirrored from the first-angle symbol, stating the American convention.
A long-dash-dot line marking an axis of symmetry or a circle's centre.
A line of short even dashes, showing an edge concealed behind material.
A circle with a diagonal stroke, marking a dimension as a diameter.
A capital R before a dimension, marking it as a radius.
A flat-bottomed bracket shape, calling for a flat-bottomed enlarged hole.
A shallow V shape, calling for a conical widening at a hole's mouth.
A check-mark-like tick with a long arm, carrying surface texture requirements.
An arrow and horizontal reference line carrying weld type, size and process.
A rectangular box divided into cells, stating a geometric characteristic and its tolerance.
A parallelogram, specifying how flat a surface must be.
An upright T on a base line, specifying squareness to a datum.
A boxed letter on a filled or open triangle, establishing a reference.
Two triangles meeting at their points, the generic valve on a flow diagram.
A ball or flap against a seat, permitting flow one way only.
A circle with a triangular wedge, marking a pump and its flow direction.
A circle on a stem with a pointer or letters, marking a pressure indicator.
A circle or rectangle crossed by a zigzag, marking heat transfer between streams.
A flat-backed D shape, outputting true only when every input is true.
A curved-back shield shape, outputting true when any input is true.
A coil beside a switch, showing a circuit that a second circuit operates.
A resistor with an arrow touching it, marking a variable division of voltage.
A small rectangle between two plates, marking a quartz frequency reference.