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Scoring and bending
is one of the most important ways of constructing jewellery. Scoring is
a method of obtaining very sharply defined bends in metal sheets. The angle
of the bend is determined mainly by the amount of material removed from
the groove. It allows rapid and accurate work to specific angles and parts
being soldered stay in place during heating without falling apart. The grooved
cross section can be arrived at numerous ways, my favorite being separating
disc followed by needle files of the appropriate angles. Other methods include
photoetching, chasing tools, chisels, gravers and other approaches mentioned
later in this section.
No matter how one makes the groove for scoring you get essentially one
chance to make the bend which is then flushed with solder. If you score
and bend and find that your angle was not correct all is not lost. Flux
the clean scored bend. Anneal. Place in hot running water to get rid of
the flux (not pickle!). Bend it gently back flat without overbending at
all. Complete any additional scoring that has to be done without stressing
the bend. Reflux, anneal, remove flux in hot running water again and bend
up. You only really get one chance to do this kind of thing. Note the
insistence on hot water instead of pickle. This is because pickled surfaces
do not take solder well, do not induce solder to run into seams and do
not fill well. Another approach which is fine with small objects but is
not wise with scored seams over about 2 cm long is to flux and then heat
to anneal. While the metal is hot one bends it up by pinching with tweezers.
The metal is very mobile and forgiving in this state and one can sometimes
make an almost right angle bend apparently become one by doing this. It
takes some heat control however because too hot and it breaks and too
cold and it breaks. You don't ever want to lever back and forth on scored
seams hot or cold.
A file tang may be easily converted into a scoring tool. This tool is
extensively used in traditional box making and I would recommend it for
scored straight lines longer than about 6 cm. The tang is heated and bent
over, then air cooled and filed into the desired shape, usually a face
like a beveled grave which faces towards the body of the file. The angle
chosen represents the angle the bend will be made to. After checking to
see that the tool cuts into metal and that the file provides a comfortable
pulling angle for the hand it is hardened and tempered. The metal is ruled
and the score started gently. It helps if the metal is clamped firmly
down with C-clamps and little cardboard pads. I usually begin by drawing
the file tang towards me gently against a metal fence clamped to the metal
as well. Clamp everything to a disposable board of wood as when the tang
point comes off your metal it digs into whatever it is on-better the board
than your desk. One turns everything around at least once so that there
is an even depth to the cut. One always tends to put more pressure near
the end of the pull. It is gone over many times, until the cut is almost
through. A raised line will show on the far side when it is about right.
I've used this to cut large sheets of metal quickly by grooving it using
a plank as a fence and then, standing on the plank bent the sheet back
and forth several times until it broke off cleanly. It was very fast.
Silicon carbide separating discs are superb for scoring metal for bending,
particularly when the metal sheet is less than 4 or 5 cm across. One usually
follows up with the appropriate angle of needle file or another scoring
tool. While I was originally taught to use discs for catch building which
involves only straight lines I discovered that they are superb for curved
line scoring. Advantages include no disturbance of a textured sheet metal
front surface while gaining enormous changes in plane. This is how many
of my own pieces are done. Basic tips for scoring with the disc include:
anneal the metal before you begin. Do not press hard; if the disc wears
quickly you are pressing too hard. The disc is very hard (nine and a half-it
will cut ruby and sapphire) but brittle. Let it cut its own way. Wear
safety glasses and breathing protection-the dust is not good for you.
Let the disc drift gently away from you (right handers), if you pull it
towards you it will tend to sink rapidly through the metal. Go over the
same area a number of times. Because the disc wants to leap over the edge
away from you and come back on the other side lift the disc off before
you arrive at the far edge and turn the metal around so the part near
the edge is towards you before continuing. When you see a raised line
on the other side it is time to stop. If you go through burnish it closed
before soldering.
Separating discs are also great for short run scoring and bending like
making bezels for fancy cut stones or angular structures. Assuming a strip
of metal up to a centimeter wide and about a millimeter thick one scores
most of the way through until the raised line appears on the far side
and then folds the metal up. From the cut side one takes a regular sawblade
in a sawframe and gently cuts outwards towards the corner. Then the strip
can be further bent. This is repeated until the exact angle needed is
arrived at. Then one solders the join and proceeds to the next bend. In
this way it is a very quick matter to fabricate an accurate angular strip
construction. If you have a little experience you can usually do two to
three cuts and bends before soldering them at the same time.
One often uses needle file; to widen scored lines to specific angles.
Often this is a right angle so one needs a 90 degree angle. However if
a square needle file is used one tends to rock it slightly and so the
angle obtained is too large. If one were to use a 60 degree triangular
needle file then one can work up towards a right angle with far more control.
The last few strokes are then done with the square file. It is better
not to count on perfection in working.
I have found that if one breaks off the ends of a square or triangular
needle file and grinds them to the same angle as a graver they become
a file-graver combination;. They can widen a separating disc cut or other
scored line to an exact angle. Held at one angle they are a file and at
a slightly different one they are a graver which saves having to pick
up and put down a tool.
Karen Cantine from Edmonton, Alberta has developed a method of scoring
for holloware construction that is called '.i.planish scoring;'. She takes
a piece of metal and holds it against a right angled edge and then planishes
with a slightly crowned planishing hammer against the edge, until the
line shows almost all the way through. The metal is then annealed and
folded into shape. This gives very quick crisp angled bends similar to
construction in outward appearance. One can with judicious use of curved
right angled surfaces also produce curving scored and bent surfaces with
this approach. I've planished onto a chasing tool for a similar effect. I use soft iron binding wire or hard brass 20 g wire for scoring and
bending. I press it most of the way through the metal with the rolling
mill, anneal and bend up. It does straight lines and curves. One can also
tape the wire on to the metal and then planish it in for scoring, bending
and decorative effects.
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