The times. [volume] (Richmond, Va.) 1890-1903, 1895-05-12

bolt. 40 that the zinc coating dries while
the tube slowly rcvolves, which prevents
the zinc being thicker on one part than
on another which would otherwise be
the case. The pipes are then taken 70 the
threading machine, and the ends are
threaded the same as before. The pipes
are usually done up IN bundles OF from
three 10 six, according 20 their size, and
piled in racks. ready for shipment
Tho process Of making pipe described
above Us what Is known as tho butt-weld
process. the name being taken from the
manner In which the edges OF tho strips
are butted together and welded Another
method Of manufacture which IS known
as the lap-wcld process, makes stronger
pipe, but for all common uses the butt
weld is considered amply strong In the
lap-Woli process az the name implies
the strips or skclp are taken 10 a machine
which parcs both edges down 20 about
pne-itt ttir original thickness, and
when the tubes are ready for welding
these edges are Tapped over on each
other about half an inch.
Iupes That have 10 stand great pressures
are nearly always made IN mis- way. as
for instance. the pipes used I'm locomotive
boilers. which arc called boiler tubes or
nnes Tho greatest possible care cxer-
cisco 10 the manufacture Of these tubes.
Tho material which goes into the skclp
Us very carefully selected. being usually
ma1' OF charcoal iron, which during man
hidtiure BIS frequently analyzcd 10 SEQ
that ir is Of the required strength. When
tne tubes are ready for Welding an iron
hdil is made 20 pass through each tube at
tne Same time it IS drawn through the
IRON welding ring. This has the effect
n forcing tho heated metal mp against
tho ring with moro than ordinary pres
suro and makes the weld more perfect
Boiler tubes are being made quite cX-
t0nsiFcly al present from steel and the
numerous discussions that daily take
place as 10 the relative merits Of steel
and iron boiler tubes would ON a small
volume Up 20 the present time tho trou-
Doe with steel boiler tube has been that
the weld was usually imperfect, owing
TO tho fact that steel Will not weld as
readily as iron. This defect. however Is
not ass serious az present as 10 has been
as the poculiaritics Of steel arc hecom-
ing better known. The difficulty mas
been that the manufacturers have been
treating steel in the same manner as they
were accustomed 20 treat iron, without
stopping 90 consider that steel is Of dihcf-
cut structure from iron and must neccs-
sarily Dee treated in ii manner peculiar L
itself
pipe that is known as seamless
drawn tubing is manufactured quite eN-
tcgAytly in England and Germany. AS
its name indicates 81 is made without
weld OF any kind. The process Of making
This tubing is secret 90 "a certain cN-
tent. and fcW, 81 any, Americans have
attempted fits manufactures lu a general
way. 80 is made boy heating solid block
OF iron or steel through tho centre OF
which "a hole of "a certain size has been
drilled. and thcn. by The aid Of special
machinery drawing out The metal around
This hole until "a tube of the required
length and diameter is obtained.
1852 this method. 10 is possible 10 make
very strong tube, and II IT'S cost were
NOT so great. tubes made in this way
would soon displace all others. The tubes
used in the framework Of bicycles are
made from drawn tubing, which is near
ly AN imported.
For she conveying Of water no pipe has
yet been found that in any way COM
pfros with ordinary cast-ron pipe, and
lfs uniform use all through the civilized
world viii readily confirm this fact. 10 is
perfectly smooth and uniform I'm the
bore giving little resistance 10 the flow
of water. the lengths are easily handled
and Joined together. and Don addition TO
this DO viii stand am enormous pressure
where equally distributed whether ape
piled externally or internally. This pipe
is cast in mold of sand having a. core
of the same material for fits centre. Both
the mold and core are Thoroughly baked
before the meltd iron ls run ga. 10 pre-
vent amy mixing OF sand or dirt with the
iron and greatly decreasing the liability
OF hlow-holes in the finished pipe. The
pipe Is cast ou end iu lengths of twelve
feet. which makes the mold twelve feet
hieh. Casting iu this manner secures a
perfectly solid casting cylindrical in
bore and of uniform thickness, which
would not De- the case were the pipe cast
on ITS side. The casting, after IL has been
perfectly cleaned and inspected SIS placed
Boo an oven and heated until the pores Of
iron are we'll opened. when 10 is immersed
ln "a bath of "a patented coal-tar varnish,
where 10 ls allowed To- remain until q coat
ue is evenly formed both inside and out
side of The casting. This coating prevents
c0rros.0n ANA guards AGAINST any foreign
matter alhoring 10 the inside OF the
pipe. 10 also forms inside OF the casting
au tnamollCl surface for the flow OF the
water which greatly lessons friction and
makes less power necessary 10 force the
water through "a given length OF pipe.
a projection called bell is cast on one
end of each length of pipe into which the
other end fits. and the joint Is made wa
1er-tght hy packing with lead and
oakum. These cast-iron water pipes are
scycuty-tw0 inches I'm diameter. They are
familiar sight along the street curb of
any large city, especially where the
streets are torn Vp as frequently as they
arc I'm Chicago.