New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1876-12-02
THE BROOKLYN BRIDGE.
QUALITIES OF THE CABLE WIRE.


Sealed proposals were received b. 5be Trus-
tees Of tho NewYork and Brooklyn Bridge up 20 last
night for tlc manufacture and delivery ia Brooklyn q
3t0O nc tons or Gs0OGOO pounds Of steel cable wc'
10 DE Used In making the cables which arc to support tAe
roadway OF the bridge. The officers state that try hope
10 obtain this material for about S5coJJJ Dut say --ey
do think any oi the bids, which now all H. VIII 10
low that sum, and they may have 70 give as b-A
as 9l,OoOOOO The bids, only few 10 number, VIII not
De opened until Monday. The following facts about the
wire obtained from the officers or thc spechcaoa'
The general character Of the wlo i 70 be as follows;
y must be made o. steel hardened tempered and 2a-
vanized The size ofthe wire shall be No fall BfnIng-
ham gauge. Aleugth OF If feet must weigh exactly l
pound before IL Is galvanized. Each wire must have
breaking strength OF not less than 340O pounds TIC
elastic m5 must he not less than 400 OF the breaking
strength, or 800 pounds Within this limit o. elasticity
it must stretch Uniform rate Tho rods of which the
wire made must be OK superior qus'tyoi steel, sua-
bic 10. wle purposes 10 is not implied that Che highest
priced steel shall be used, such ID required for fine
cutlery I'm an previous bridge cables, charcoal IRON
wire Of either 40 10 or No 9 gauge was used.
In iron wire 10 is well known tlas
remarkable increase in strength is developed by the
process OF cold drawing. Thus baf one inch square
having q strength OF 10000 or 10000 pounds 10 the
square inch, viii show aIate Of lom 10000 60 100000
pounds Tor each Square inch of section, when drawn
down 90 70 or Nc. 10 size. IL steel tbs s also true
% moderate extent, while the process OF tmIerus and
harl E- E-ll further .lDreases the strength The use
o. this size LAS three advantages The rs- is that fewer
wires required o. make p the cable, thus reducing
labor Tic second ia, that i,s greater weight offers
greater resistance TO the wlud-a most important con-
sderaon when laying cable in locality as exposed as
the present Tie third, that Offers less COMPARE
tive surface rust The Of size much coarser than
No. H., however, barred BY the extreme stiffness OF the
material maxim It very troubles TO handle. In the
question OF strength, regards tine choice between
su iron and the various grades Of steel Tor cables, Il is
found that the great length OF the main span az
once exc. udes the use Of iron or the lower
grades OF steel. Even with the quality called
FOR In these specifications, Oue-thud OF JAc
strength Is taken in supporting is own weight hence
thcu OF iron wire the lower grades Of steel Il not
admissible, because 10 would ueoesstate cable Of such
gins and tua5 10 would become uumSnageaoie, ana
involve Tie greatest difficulties in making t The rate
OF strength decided upon, namely, 100000 pounds 70
the square inch represents .lr moan VI al the objects
That ia desirable TO attain. lt is true that steel wire Of
4 very much higher rate oil strength can be made lEs
would produce a cable much smaller than j. inches
IN diameter Now 20 f. just undesirable % l@v3 100
small a cable as too large q certain bulk on cable
Is absolutely necessary order 70 give mass. and the
inertia TO resist dangerous oscillations u te cable itself
The dimensions OF the anchor chains, the sizes OF Tie
saddles and plates the weight of the anrhoraee and the
shapes OF the towers, have all been proportional for
cable - inches in diameter and made OF s'ee. wire Of
Oh, strength above given.
In ease the blIets or rods not made b. the con-
tractor for the wre It is 20 be understood that the iu
spcctor on the part Of the trustees Is 10 have ample
facility satisfy himself. By ocular proof that they are
actually made Out Of suitable steel and from uniform
stock Tho standard called for demands that Ills steel wire
shan De ia uniform Medium quality; thai Is It must be
neither tol hard high In frs character nor loo soft or
low in it temper In order to insure this uniform Quail
it 10 is necessary that all the cabcwire shall undergo
the operation OF hardening ana teleertng. There are
several methods known by which this is done,
some controlled by patents and others Of a
secret nature. Whatever the process pursued
by the manufacturer, the inspector must satisfy
himself that every ring O wire Las undergone tie opera
ton. the cables 20 Doe eNpUsed to thc salt sea air.
the ordinary means Of prorecton-as has been proved
by expercuce-such paint oil, OF varuish, are made
1uate TO prevent rstiug. The only safeguard coat
ing OF zinc, which acts by ITS absolute air nghtness as
well as by i.- -lgauic action, and Is not easily aDrlded
All tue wire called f1r must Doe straight wire thai X
20 say when RING is mroHad uuou the Goor the wire
must remain perfectly straight without auy tendency
% spring back te coils. This straight coHdir.on mast
not produced ay the OF srghteuip- machines OF
amy kind .le} only niur- the strength and elasticity
OF The wire. As the cables can OIy De laid Mp With
straight wires this necessity E obvious. I'm the manu-
facurr m order % produce straight wire, II is nene9-
tr,g n m . ,--i,+ lima. nm 4cr ra ia hls tension 70
The guide sheaye wiudirc drum. and - p!a'- mo
-etye or 3.Im at such saUce 80 Jo e-'-it ,e Tire
10 Pee eu aHd before - COe thereon, sut also
mase tHe -heave or t-um OF sitA tDr +7 VAL not
cause permanent bending Yl tse coli0'! wiz
Owing To- the uugeIrlI cIa oter ol STEEL and ~ per
-tdss ut REJECTION that ar A... attends Gee Au.'u'L
selection may uayo undergone in Jhe r1riNu- ace' NJ
fs manufacture. the engineer considers Il absolutely
necessary tlat every ring sotli tndrrs' I.et WEN
finished. There VIII Doe hour kinds nj tests Tor me wire
First, vertical strain vii ne sphiIrd ~ pre- % Jet
creased 1900 pounds, te stretching Of tie WY Deins
hou,snd,l OF m inch Tns will b, applied
% oEe ring oG of every i9ry In the second place one
fe't long On and placed IA testing m-'s me win
gauge, attached and grad ate as 70 read tue
stretch OF i've feet OF length 90 onecuGoSndIA oi orc
ioui. Every Iins VIII ue tested ny having piecS 10
inches long cut from either thd' placed I'D q Test
one t"ot wire. Every ring also VIII De subjected 10
bending tr, 10y cutting OF piece one foot long and coil
ina u nrrr, when II it breaks il viii bee rejected The
tIOn u random here Iud there, a. II does IN iu-
1c tt NO bad WORT can possibly pass III inspection.
In these tests uuattauIne -tandd nu- been set up.
but the requirements -uJl can be nLti Win case
and cert1iu,y BY m.mJ manufacturers.
Long rims, are indispensable The weight must average
Ii and thcy nav he ms much heavier as c.u b. made
provided lie ends OF uniform saHsCtr. By having
long the time and iAJor ui splicing Tie wire u IT,
du,eF Yrgooftionably Tne splice Bs.Gg rhe weakest
.nu tr AVERAGE strength T. Increased by having long
Iing, The wur Is, besides, ct cotrsg size that
v acros he main span Hence Al tn hest t1s relative
number OF spices VIII be far gIrater than IA ANY pre-
yul, cable The Pc eui4r deliveries %. ,fIe viii begin
F.b l. I--7 Ihc amount Of these nj tsly deliveries
must p. no lees uau 100 tons, and On case 10 snla Dc
found that the CJDleuJAlug proceeds faster ta4u 20
present anticipated tine mIuuf Irturer must increase
ils amount Co 300 tons. All p-rsous who bid on tsis
wire were required % send samples Zoe acn.rd4ucr with
te specifications weighing less than 100 pounds aud
containing two rings.
The standard FOR the bids wac nj so much pound in
coid 10 was deemed beet % place the bids ON Sud
basis u ord .r tO eliminate, tlg question o. the probable
gtas Ill tine value OF currency Tor the period ~
over which he contract "lL extend. IL would Do
ltsrsl flat the contractor w0I.d be forced 20 allow
I.. ID would necessity. De against The interests Of
AZ, bridge. TIE successful bidder VIII DE required 10
of -- IN IIf. rfr