American Millwright and Miller, by David Craik, 1870.
The Practiced American Millwright and Miller: Comprising the Elementary
Principles of Mechanics, Mechanism, and Motive-Power, hydraulics and hydraulic
motors, mill-dams, saw-mills, grist-mills, the oat-meal-mill, the barley-mill,
wool-carding and cloth-fulling and dressing, wind-mills, steam-power, etc.
By David Craik. Millwright. Illustrated by numerous wooden engravings and
folding plates. Philadelphia: Henry Carey Baird, Industrial Publisher, 400
Walnut street. 1870. Price, $5.
A HANDSOME volume of over four hundred pages, containing numerous illustrations
of designs, models of construction, and explanatory diagrams. It forms undoubtedly
an important additions to the literature on this subject. While the various
topics are treated with marked clearness, no expressions are used which
will not he readily understood by any practical mechanic. On points which
have been the subject of controversy and dispute, the author's opinions
are backed up by the results of practical tests and experiments made by
him, with a view of giving only the most reliable information possible.
In portions of the country thinly inhabited, and where very few properly
educated mechanics are to he found, men totally unacquainted with the subject
of millwrighting often impose themselves upon men who contemplate the erection
of mills, secure a liberal compensation for their services, and the result
is an improperly constructed mill, which utilizes but a small fraction of
the power which might be obtained from the water. Several instances of this
kind having come under our own personal observation at the South, we the
more commend this book to the careful perusal of those about to build water
power mills. Although the information here given is very detailed in nature,
and will of course be of greater benefit to those already tolerably conversant
with mill-work, still any one of ordinary intelligence would be able to
derive sufficient information from it to detect an impostor, and save himself
from being glaringly swindled.
In the first place, a few notes are given on such well-known mechanical
devices as the lever, wedge, screw, inclined plane, pulley, crank, fly and
balance-wheels, followed by chapters on machinery for transmitting motive-power,
and the peculiarities and properties of water.
About fifty pages following are devoted to the question of water-wheels-
undershot, overshot, central, and spiral discharge which is clearly explained,
and cuts of the various kinds of wheels introduced in the text. The remainder
of the work is devoted to the subject of mill-dams, saw, grist, and barley-mills,
followed by chapters on wool-carding, fulling, and dressing, wind-mills
and steam-mills. In the back of the book are five plates of working drawings,
made to a scale.
In order to show the clear, simple, easily-comprehensible language used,
we quote the following from his chapter on mill-dams:
"Log-dams, in a locality where timber is plenty, are cheapest, arid
easiest to build. If the bottom be rock or other good foundation, begin
by laying a large log across the stream, at the down-stream face of the
intended dam; this you will extend from bank to bank, by laying one log
at the end of another, having each piece as long and large as possible,
taking care to clear away every thing that will wash out from under; and
where hollow places occur, put short logs across under; so as to give it
a safe foundation. Then put short logs across this six or eight feet apart,
their butt ends lying upon the log and their top ends upon the ground, up-stream
from this; you will now place another tier upon these, above and parallel
with the first one, but inclining slightly upstream; then another set of
short ones, their butts upon the last tier, and top end upon the ground
beside the first cross-ties. These must be a little shorter than the first
ties, to admit of laying a smallish log on the ends of the first ones, and
up into the angle formed by the second ones; you can now lay "skids"
upon these small logs, and proceed to roll up your third tier of large logs,
along the faces. Care must be taken to notch them a little where they cross
each other, to insure their laying safely, or block them secure with a stone
or piece of wood where the small ends come.
"Your next tier of ties must be notched well down at the small or up-stream
end, and you must proportion your two parallel tiers of logs, and these
ties, so that the front or breast will rise enough faster than the rear
to keep it like a portion of an arch, and have the cob-work, when finished,
fit the rafters; that is, the larger tier of logs at the breast should support
the rafters near the top, while the smaller tier at the rear should support
them near the middle, and the lower ends of the rafters rest upon the rock
or bottom. It will be seen that a breast work so constructed is like a portion
of an arch or circle, of which the foot of the rafter is the center, and
the front of the breast work the circumference; and the more weight is put
upon it, the stronger and more solid it becomes. Care must be taken not
to carry it too high or steep, for the length of rafter, (or radius,) as
in that case time force of water behind might slide it away in a body.
"If logs are convenient, this may be covered with them, like rafters,
touching each other, taking care to fit them well and chink the cracks.
The moss on trees and old logs, in damp places, is good to chink these cracks,
as it grows and increases in such a place, instead of washing out. Cedar
bark, pounded soft like oakum, is also good. Such a covering requires but
little graveling to make it tight, as time pressure of the water forces
the packing down into the seams forced by the round logs, where it is not
easy to wash it out, or displace it by any other means.
"Such a dam is cheap, strong, and durable when there is a constant
supply of water; but on small streams liable to dry up in summer, and allow
the logs to dry and heat and check, they very soon rot, and are, therefore,
not to be recommended for such a situation.
"Where logs are not so easily obtained for covering, place rafters
about three feet apart, upon the cob-work, with the butt ends down, and
plank crossways upon these, using thicker planks near the bottom, if the
dam is deep, while thinner ones will answer near time top, except where
the water is intended to run over, where strength is required to withstand
the ice, flood-wood, etc. The lower planks should be scribed down carefully
to the bottom, and all the others beveled about one eighth of an inch off
the upper or inside corners, and half way through, to allow dirt to get
in to make it tight; the ends should he sawn open inside also. If the plank
were partly seasoned, and put on with pins, each pin being draw-bored a
little; to pinch the plank tight, then a little gravel along the bottom,
and a little saw-dust stirred in when the water is fist raised, will make
it tight. Pinning and draw-boring is a tedious process, however, and it
is more common to spike the plank on and cover with gravel.
"Great care must be taken with this, as with every other kind of dam,
to splice it securely onto the bank at each end, and one principal consideration
should be to attach it in such a way, that, as the dam settles down, (as
it certainly will, to some extent,) it may settle on to the bank, amid secure
it as much as possible against frost, and not away it, to cause a crack.
These ends, and the place where the waste water runs over, are the most
difficult parts to secure.
"So far, we have supposed the dam to be built upon a rock, or other
good bottom, and in such a situation there is little trouble with the waste
water; but upon a soft bottom it is a very different affair. A carefully
constructed chute and apron are then indispensable; and in some bottoms,
composed of sand or mud, it is necessary to drive piles to a great depth,
and across the whole breadth of the river, to get a foundation sufficient
for building a dam. In one instance, a double tier of these piles was driven
by machinery, the first twenty-five feet long, and the second row breaking
joints upon these, fifteen feet long; these were driven into the quicksand
writhe the lower ends slightly inclined up-stream, and the tops bolted to
a stick of timber. Upon this the dam was built, composed of crib-work of
timber flanked with stone at the center, each end being flanked by a wing
of frame-work, rafters and plank. The whole channel, for some distance above,
was filled up with "fascines," and the banks below were protected
by the same means.
"These fascines are small bundles of brush wood tied up by three withes,
about a foot apart. They are placed in courses like shingles, each course
overlapping another, time upper end inclining down-stream, and each bundle
fastened down by three stakes. These stakes are three or four feet long,
the small end sharpened, and a pin-hole bored through the butt end, in which
a pin about eight inches long is driven. These stakes are thrust through
the fascines, one at each writhe, and in an oblique direction, being entered
above the writhe, and passing through below, it at the under side. They
are driven down by wooden mauls, until the pin comes upon the writhe, and
hugs the whole bundle down tight.
"Another dam, in a similar situation, was afterward built without the
pile-work, the bottom and edges being protected by fascines alone; thus
dam has now stood for many years, and appears to be safe and durable. And
yet another was made by rolling in loose stones, large and small, just as
they came, mixed plentifully with pea-straw, until the channel was filled
completely up, and formed a rapid. This last stands equally as well as the
others, except that a large tree embedded in the bank, which was not discovered
at he time, caused a small break the first season.
"These dams are all upon large streams emptying into Lake St. Peter,
in Canada, near the sandy north shore of which lake they are constructed.
It is worthy of remark, that all these streams carry a large amount of sand
and mud in solution in their waters, especially during freshets, which very
soon fills all the interstices in these fascines, or pea-straw and stones,
and renders the whole mass solid and compact. This result would not take
place in a stream where the waters were clear and free from sediment, and
the filling would have to be supplied as the work progressed.
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