Manual of Purpose-Made Woodworking Joinery

12 Drawings and rods

three- dimensional views (length, width and height) of
drawn- objects as they should be displayed separately
in relation to each other on a drawing.
The two main methods of orthographic projection
are 1) First- angle (or European) projection for construc-
tion drawings and 2) Third- angle (or American) projec-
tion for engineering drawings. Only method No.1 is
covered here.

First- angle projection

Figures 2.8(a)(b)(c): The open, topless box illustrated
in Figure 2.8(a) is used as a means of explaining the
principles of first- angle projection. If you can imagine
the three- dimensional object (a joiner’s handmade
bench hook) shown in Figure 2. 8(c) to be suspended
in the box, with enough space for you to walk around
it, then by looking squarely at the object from all
four sides and from above, the views seen against the

surfaces in the background, would be in their correct

position orthographically when you open- up and lay

out the sides and base of the box like a drawing.

Laying out the box

Figures 2.8(d)(e): As shown at (d), the topless box is

opened out to give the views as you saw them in the

box and as they should be laid out on a drawing. This

layout is not always followed, because views are often

separated onto different drawings and become unre-

lated orthographically. Mainly for this reason, descrip-

tive captions are used, resulting in ‘PLAN’, ‘FRONT

ELEVATION’ and ‘SIDE ELEVATION’, etc, being

written below (or in a title box) of most drawings.

Figure 2.8(e) shows the BS (British Standards)

symbol recommended for display on construction draw-

ings to indicate that first- angle projection has been used.

Figure 2.8 (a) The topless box above is used to explain the theory of orthographic ‘first- angle projection’; FE = front
elevation; R/H SE = right- hand side elevation; L/H SE = left- hand side elevation; RE = rear elevation; and PLAN is the
view from above; (b) Four dihedral seams of the box are theoretically split to open it up and create one surface; (c) The
three- dimensional object used in the illustration at 2.8(d) below.

FE FE

R|H

SE

R|H

SE

L|H

SE

L|H

SE

RE RE

PLAN

PLAN

(a) (b) (c)

= Vertical planes

Right-hand

Side elevation

Left-hand

Front elevation Side elevation

Plan

Rear elevation

*

****

** = Horizontal plane

**

(d) (e)

Figure 2.8 (d) Box laid

out orthographically (e)

First- angle projection

symbol.