Department of Technological Education

Auxiliary Elevation

The elevation and plan of an angled bearing block are shown.

Project an auxiliary elevation in the position indicated Department of Technological Education Plan Front Elevation

Drawing Datum Lines

Start by projecting the extreme limits of the Auxiliary Elevation onto the given base line.

This should be done at the required angle – in this case 45 o .

Indicate the position of the two datum lines that will be used to calculate heights.

Department of Technological Education Plan X Front Elevation X

Department of Technological Education

Finding Centres for Curves

Measure the height of the base and the height to the centre line.

Transfer these dimensions to the Auxiliary Elevation.

Draw suitable lines to indicate these positions.

Plan X Front Elevation X

Construction of hole (1)

Looking at the drawing you should be fairly confident that the hole on the Auxiliary Elevation is circular and can be drawn using compass’s.

This fact can be checked by measuring the width and height of the hole from the Plan and Elevation and also confirming that there is a centre line to indicate that the shape is circular.

However, if you are not sure it is worthwhile constructing the shape.

Working with the front surface of the hole, project random cuts onto the Plan and then onto the Auxiliary Elevation.

Department of Technological Education Plan X Front Elevation X

Construction of Hole (2)

Measure the size from the datum line up to each of the points on the circle.

Transfer these dimensions onto the Auxiliary Elevation.

Draw a smooth curve through each of the points.

Department of Technological Education Plan X Front Elevation X

Drawing Top Curve

The same process can be carried out for the round top of the angled bearing block.

If you are confident that the top is a half circle then the shape can be drawn with compass’s using the existing centre lines.

However, if you are not sure, measure the heights for the curve using the existing random lines and transfer the heights onto the Auxiliary Elevation.

Draw a smooth curve through each point.

Department of Technological Education Plan X Front Elevation X

Drawing Outlines of Top

Before starting to draw the base of the bearing block, the top can be finished by darkening the outlines.

Department of Technological Education Plan X Front Elevation X

Drawing Base

Project each of the corners of the base from the Plan to the Auxiliary Elevation.

Each of the edges can be darkened to finish the drawing.

Department of Technological Education Plan X Front Elevation X

Finished Drawing

This slide shows the finished drawing.

Department of Technological Education Plan X Front Elevation X

PowerPoint Presentation produced by John McRae, Nairn Academy 2003