The Many Mutations of Metal
i
ei0n. A drill press， fitted with Whether as a porch rail， a hinge or a hoe blade， metal is prized for its
[wistbit makessh0rtw0rkof hardness and strength. It can stand up to loads and conditions that
gh ~cn-[nick aluminum
w0rkpiecet0thefable of the would instantly shatter or slowly rot away most other materials.
lamps makes it possible to Yet for all its brawny virtues， metal is the most mutable of materials
ely before drilling and tg keep both in its manufacture and after you get it home.
~ing while the hole is
，0sslu e t0 aehievet01erances At the refinery， smeltery or mill， the very chemical composition of
)usandths0fanineh. metal can be changed to suit its intended use. Iron， hardened with
just a trace of carbon， becomes mild steel a material malleable
enough to be bent into rails or balustrades and ductile enough to be
drawn thin for guying wire or piping. With more carbon， iron be-
comes tool steel--a product hard enough to cut， pierce or grind most
other metals. Similar alchemies can be performed with other metals:
Copper mixed with tin makes bronze， an alloy far easier to cast than
pure copper; aluminum， used in its pure state for high-voltage elec-
tric lines， is transformed into far tougher duralumin with an admix-
ture of manganese， copper and magnesium.
But matching metal to its intended use does not stop at the factory
gate. At home you are just as free to alter the size and shape of metal，
and in some cases its physical properties as well. The most dramatic
changes， of course， are achieved when the metal is returned to its
molten state with a torch or a furnace; the use of heating equipment
for cutting， welding， forging and casting is explained in Chapter 3. A
surprising number of manipulations， however， can be accomplished
without heat. Specialized snips， cold chisels， saber saws fitted with
ferrous blades， and hacksaws all make short work of cutting cold
metal to size. High-speed twist bits pierce it easily， and an incredi-
ble array of manufactured fasteners--from tiny pop rivets to machine
bolts as thick as a man s wrist--are available to join it. Metalworking
tools called taps and dies are used to thread metal pieces themselves
to serve as their own fasteners， and specialized jigs and bending
tools many of them homemade--facilitate altering its shape.
Yet for all the ease with which it can be rent， bent， pierced and
polished， metal is ultimately a material that demands and de-
serves precision. For one thing， seldom can mistakes be fixed easily.
Holes drilled in the wrong place cannot simply be puttied over and
redrilled. A slightly wayward joint cannot easily be straightened out.
But the precision required is a reward in itself; and the pleasure of a
finely crafted balustrade or bracket will last long enough to justify
the few extra hours necessary to craft it properly. Witness， for in-
stance， the finely wrought iron grilles， many elaborately embellished
with quatrefoils and fleurs-de-lis， that still guard the windows and
doors of Venice. They were forged decades before Christopher Co-
lumbus set foot in the Americas.
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