The Municipal and Sanitary Engineer's HandbookBoulnois, H. Percy (Henry Percy)
Science
The Municipal and Sanitary Engineer's Handbook
Boulnois, H. Percy (Henry Percy)
Municipal engineering; Sanitary engineering
It will be seen by the above table how different are the results
obtained from materials of the same character.
Breaking stone for the purpose of using it as a road metal was, until
comparatively recent years, always effected by hand; now, as in other
cases, machinery has stept in and somewhat supplanted manual labour.
Hand-broken road metal, however, still finds favour with road surveyors;
it is better broken, and in some districts, the occupation finds
employment for persons who otherwise would be thrown on the rates for
support.
In breaking stone by hand the breaker sits and strikes the stone with a
small cast-steel chisel-faced hammer, weighing about one pound, at the
end of a long, straight-grained but flexible ash stick.[33] The breaker
also has another hammer, weighing about five pounds, with which he
reduces the size of the large stones before breaking them into the
proper size for road metal. This latter size is often a matter of
choice, some engineers preferring it to be broken so small as will pass
through a ring of only 1¹⁄₂ inch in diameter; others are content with 3
inches, especially where the roads are steam rolled. An old method of
gauging used to be “such a size as the stone breaker could put in his
mouth,” but this was unsatisfactory to all persons concerned, and “to
pass all ways through a ring of 2¹⁄₂ inches internal diameter” is now
the size most generally adopted.
Mr. Codrington says[34] “a good stone breaker will break 2 cubic yards
of hard limestone to the ordinary gauge in a day, and some men will
break more. Hard silicious stones and igneous rocks can only be broken
at the rate of 1¹⁄₂ or of 1 cube yard per day; of some of the toughest,
such as Guernsey granite, a man can only break on an average half a cube
yard per day. River gravel, field stones, or flints, which are already
of a small size, can be broken at the rate of 3 or 4 cube yards per
day.”
This may be taken as fairly representing a day’s work, the price for
breaking however must vary considerably in different localities on
account of the variety of the stones to be broken and the value of
labour; in some districts the road metal does not cost more than 1_s._
per cube yard, in others 2_s._ 6_d._ and 2_s._ 8_d._ is not considered
too high, and it was to meet and reduce this great expense that steam
stone-breaking machines have been introduced. These machines are known
as “Ellison’s,” “Newall and Archer’s,” “Hope’s,” and “Blake’s,” the
latter being that which is best known and most generally used in this
country.
[Illustration: “ARCHER’S” STONE BREAKER.]
[Illustration: “BLAKE’S” STONE BREAKER.]
[Illustration: “NEWALL AND ARCHER’S” STONE BREAKER.]
Public-domain text, read in full here on John Shaqi.
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