Next to the scroll, the twist is perhaps the most characteristic detail
of decorative treatment in iron. Twists relieve the plain effect of
the straight lines made by the hard edges of the metal, by introducing
short curves into the design. The twists are easily made and lend
themselves largely for decoration on such things as fire escapes,
brackets, grills, gates, fences, and smaller articles, such as umbrella
stands, door knockers, fire tools, etc.
The twisting is done best while the iron is cold. If done while the
iron is hot great care must be taken to check up when the lines begin
to run too close together. Take a bar of square iron, fasten one end
in the vise, and with a monkey wrench on the other end give the metal
a twist. Only square bars show a change in the shape after twisting.
Round stock when placed in the vise and twisted shows no change in
shape. However, two pieces of round stock twisted give a very pleasing
effect. A braided strand is made (1) by welding the ends of two pieces
of round iron together side by side and twisting them, (2) welding ends
of two more pieces of the same size and length together and twisting
them, (3) by welding these two twisted bars together on both ends and
twisting them in the opposite direction. This gives a braided effect
which is most decorative. However, the square stock gives the most
satisfactory result in all of this twisted work.
Handles can be made by reducing square stock, leaving the centre larger
and drawing the ends out to a taper and twisting this tapered part.
Begin the twist in the middle and let it rise gradually toward each
end. Great care must be taken with this work, as the smallest sizes are
also the weakest and naturally bend first. To do this work successfully
the metal must be heated and driven a little each time until the whole
taper is twisted. _Spirals:_ Spirals are made by drawing a long taper
on the end of a round or square bar of small iron. Turn the end of the
bar up 1/2 in. at right angles. Grasp the turned up end in the vise;
coil the end up as you would a coil of rope. Slip one end under the
other when they come together. When the first coil reaches the centre
of the piece repeat on the other end until the two coils meet in the
middle. Heat it all evenly. Grasp both ends in the tongs and pull the
spiral out. Stop when the openings equal the size of the iron of which
the coil is made.
[Illustration]
_Ornamental bulbs:_ Bulbs are used in the same way as spirals and
twists, for decorative purposes, on andirons, grills, fences, etc.
The form shown here in the sketch is a very simple one. The principle,
however, is the same as that applied to the forging of more complex
bulbs. Select a rod of iron for a core. Reduce the thickness to about
1/2 in. for about 6 ins. long, leaving the required thickness at the
ends; 1/2 in. from the shoulder nick the bar around, cutting it almost
through. Leave about 1/16 in. to hold it to the body of the piece. Cut
the core off 1 in. from the 3-in. cut. The picture shows the method of
making the core in order to work out the problem. Select a number of
pieces of 3/16-in. round soft steel the length of the reduced piece
and place these around the core, each one fitting close to the next
one. If the space is too small or too large when the last piece is put
in make the core larger or smaller. These rods should just touch when
they lie around the core. Now with a pair of tongs bind all the rods
tightly around the core and with the same tongs put one end in the fire
and heat red hot. Cover with borax. Take on a welding heat and weld it
in a swage, confining the length of the welding to as short a space as
possible.
[Illustration]
[Illustration]
The core prevents the rods from sinking while welding and it also
keeps them in place. Reverse the piece. Put the other end in the fire
and weld as before. Weld the neck as short as possible. Heat the body
of the piece uniformly. Grasp one end of the bar in the vise and with a
pair of tongs twist the other end toward the right slowly. While doing
so tap lightly on the end with a hammer. This tends to loosen up the
rods and help the twisting. Be careful not to twist so much that the
rods will break away from the welds. Heat all again. Place it again in
the vise and twist in the opposite direction, at the same time driving
on the ends. This forces the centre out and gives it a bulb shape. The
core should bend up where the cutting is done. Now the core should be
driven out. A punch driven in against the core should break it easily
where the cut marks are made. These short ends are forced out through
the openings between the rods, and any uneven buckles or bends in the
rods should be bent or straightened as the case requires. The bulb can
be trued up while cold. A punch driven through from the opposite side
will help straighten any of the rods bent from the outside in.
The rods can be plied apart with a pair of pliers or a pair of tongs.
The surplus metal on the top end is now cut off and trued up.