Chapter CLVII: Section 99: Materials Employed in Construction

(_See also p. 224._)

=2573. Ribbed plate or tram plate.=

=2574. Trough plate for flooring bridges &c.=

=2575. Trough plate for flooring bridges &c.=

=2576. Curved ditto. Hobson’s patent.=

=2577. Wrought-iron or steel dished piston forging.=

=2578. Wrought-iron flanged manhole forging.=

=2579. Trough flooring.=

=2580. Trough flooring.=

=Iron and Steel Plates.=--It is essential to possess some knowledge of
what sizes and weights are obtainable at ordinary prices, because it
is frequently desirable to utilise the largest available, in order to
save the cost of making joints. Frequently joints are made by
riveting, not because they are wanted at all, but simply because they
cost less than single plates would do. Information of this kind is
only to be obtained from the price-lists of the iron and steel
manufactures, which are supplied to the trade.

The meaning of “maximum dimensions” is thus:--Taking a 1¹⁄₂″ plate,
for example, the maximum dimensions of which are given in a list as
40′ in length by 10′ in width, it is not possible to get a plate
measuring 40′ by 10′, for that would make a united area of 400′, and
the list limit is 150′ area. But the area can be taken out either in
length or in width, within the limiting length of 40′ and width of
10′. _The maximum area divided by any length in feet not exceeding the
maximum, will give the maximum width for that length; and the maximum
area divided by any width in feet not exceeding the maximum, will give
the maximum length for that width._ Thus, 150′ area divided by the
maximum length, i.e. 40, gives 3′ 9″ width of plate. Or 150′ divided
by the maximum width, i.e. 10, gives 15′ length of plate. And for
anything over these maximum dimensions special quotations have to be
made. But no plate can be rolled to contain the _greatest_ length and
the _greatest_ width at the same time.

Again, in reference to “extras,” many points have to be borne in mind.
Thus, as regards _shape_, any departure from the rectangular form is
an extra, as tapered plates, sketches, i.e. any irregular outlines,
and also circles. The extra, under this head, may be about 25_s._ per
ton. As regards _thickness_, plates under ¹⁄₄″ thick are an extra,
rated at from 10_s._ to 20_s._ per ton more. As regards _width_ and
_length_, quite special terms are made, amounting to 5_s._ perhaps on
each 3″, a serious item. And as regards _weight_, steel plates over
about 40 cwt. are charged extra, at the rate of about 5_s._ per 5 cwt.

To give examples: The Steel Co. of Scotland roll steel plates from
¹⁄₁₆″ to 1¹⁄₂″ thick, and from an area in the first case of 30′ to
150′ in the latter. The thicknesses advance by thirty-seconds in
thickness up to ³⁄₁₆″, by sixteenths up to ¹⁄₂″ and by eighths up to
1¹⁄₂″. The following table will give an idea of their limiting sizes,
which may be taken as fairly typical of steel plates in general. It
will be seen that I have included only a few of the thicknesses named
above.

MAXIMUM.

------------+---------+---------+-------+
Thickness. | Length. | Width. | Area. |
------------+---------+---------+-------+
in. | ft. in. | ft. in. | ft. |
¹⁄₈ | 22 0 | 5 0 | 50 |
¹⁄₄ | 33 0 | 6 3 | 90 |
³⁄₈ | 38 0 | 7 4 | 100 |
¹⁄₂ | 40 0 | 8 3 | 110 |
³⁄₄ | 40 0 | 9 3 | 140 |
1 | 40 0 | 10 0 | 150 |
1¹⁄₄ | 40 0 | 10 0 | 150 |
1¹⁄₂ | 40 0 | 10 0 | 150 |
------------+---------+---------+-------+

David Colville and Sons roll plates from to ¹⁄₄″ to 1¹⁄₂″ in thickness
with an area of 80′ in the first and 140′ in the last; other sizes
intermediate. But by special arrangement plates ¹⁄₄″ thick can be
rolled to 140′ area, and 1¹⁄₂″ of 170′. Thirty hundredweight is the
limit of weight in ship plates, and 40 in boiler plates. Plates up to
6¹⁄₂ tons weight each can be rolled at special prices. It is
impossible to roll plates exactly to weight, and it is usual to allow
a deviation of from 2¹⁄₂ per cent. to 5 per cent. _over_ weight for
boiler plates, and under or over for ordinary plates.

The Parkhead Steel Works roll ¹⁄₁₆″ plates to a maximum area of 36′,
¹⁄₄″ plates to 70′, ¹⁄₂″ plates of 110′, ³⁄₄″ plates of 140′, 1″
plates of 150′, and 1¹⁄₄″ plates of 150′ area. The limiting weights
are 20 cwt. for ship plates, and 40 cwt. for boiler plates. Above
these 5_s._ per 5 cwt., or part of the same, is charged.

The Weardale Iron and Coal Co. roll steel plates from to ¹⁄₄″ to 1¹⁄₂″
thick, with a maximum area of 60′ in the first, and 120′ in the
second; 30′ is the maximum length, and 8′ the maximum width. Circular
plates are also rolled from 5′ 6″ diameter of ¹⁄₄″ thick, to 8′ 6″
diameter in 1¹⁄₂″ thick. All ordinary thicknesses, also intermediate
between these, are rolled.

The limiting weights and dimensions of the steel plates of Bolekow,
Vaughan and Co. are 18 cwt. 80 sq. ft. in area, 23′ in length, and
between 12″ and 60″ in width. Extras are, for every hundredweight, or
part of the same above 18 cwt., 10_s._; for every foot, or part of a
foot, above 23′ in length, 5_s._; for every square foot above 80 sq.
ft., 1_s._

John Brown and Co., Sheffield, roll steel plates from to ¹⁄₈″ to 1¹⁄₄″
in thickness. A few selected thicknesses are given below.

------------+---------+---------+-------+
Thickness. | Length. | Width. | Area. |
------------+---------+---------+-------+
in. | ft. in. | ft. in. | ft. |
¹⁄₄ | 30 0 | 6 0 | 72 |
³⁄₈ | 35 0 | 6 9 | 120 |
¹⁄₂ | 40 0 | 8 0 | 130 |
³⁄₄ | 40 0 | 9 6 | 180 |
1 | 40 0 | 9 6 | 180 |
1¹⁄₄ | 40 0 | 9 6 | 180 |
------------+---------+---------+-------+

Circular and square plates of the same thicknesses can be rolled as
follows:--

------------+-----------+---------+
Thickness. | Diameter. | Square. |
------------+-----------+---------+
in. | ft. in. | ft. in. |
¹⁄₄ | 6 6 | 6 6 |
³⁄₈ | 7 0 | 7 0 |
¹⁄₂ | 8 3 | 8 3 |
³⁄₄ | 10 6 | 9 9 |
1 | 10 6 | 9 9 |
1¹⁄₄ | 10 6 | 9 9 |
------------+-----------+---------+

The Dalzell Steel Works of David Colville and Sons, make a difference
in the extras in the case of steel boiler and of ship plates. Ordinary
prices are charged to 84″ wide in boiler plates, but to 72″ only in
ship plates. Above that they charge 5_s._ per ton for every 3″, or
part of 3″. So in weight, 40 cwt. is the limit for boiler plates, and
30 cwt. for ship plates; over those 5_s._ per ton is charged for every
5 cwt., or part of 5 cwt. Circular plates for boiler ends and crowns
are rolled by David Colville and Sons, who supply at ordinary prices
the following: ³⁄₄″ thick, 9′ 10″ diameter; ¹¹⁄₁₆″, 9′ 6″; ⁵⁄₈″, 9′,
and ⁹⁄₁₆″, 8′ 6″.

As a sample of the usual limiting sizes of iron plates, I give the
following:--It consists of a few selected Snedshill plates rolled by
the Lilleshall Company, one of the most favourably known Shropshire
houses. They roll iron sheets and boiler plates from ¹⁄₁₆″ to 1″ in
thickness, advancing by thirty-seconds to ³⁄₁₆″, and by sixteenths to
1″.

------------+---------+---------+-------+
| | | |
Thickness. | Length. | Width. | Area. |
------------+---------+---------+-------+
| | | |
in. | ft. in. | ft. in. | ft. |
¹⁄₄ | 30 0 | 5 0 | 5 |
³⁄₈ | 30 0 | 5 6 | 7 |
¹⁄₂ | 30 0 | 6 0 | 8 |
⁵⁄₈ | 30 0 | 6 0 | 80 |
³⁄₄ | 30 0 | 6 0 | 80 |
1 | 30 0 | 6 0 | 80 |
------------+---------+---------+-------+

It will be observed that the limiting sizes of iron are much less than
those of steel.

The Butterly Company roll both iron and steel plates. The limiting
weights and dimensions are as follows:--For iron boiler quality, 8
cwt., above that the extra prices are, 20_s._, 40_s._, 60_s._, 80_s._
respectively, from 8 cwt. to 10 cwt., 10 cwt. to 12 cwt., 12 cwt. to
14 cwt., and 14 cwt. to 16 cwt. respectively. For bridge quality, 10
cwt. is the limit, and extras are 20_s._ and 40_s._, from 10 cwt. to
12 cwt., and from 12 cwt. to 16 cwt. respectively. Area 60′, and for
every 10′ or part above that, 20_s._; length 25′; width 4′6″; over
those various extras, ranging from 20_s._ to 80_s._