the former.
The motion is derived from a bevel-pinion which engages one
or the other of the bevel-wheels to rotate the feed-screws in one
or the other direction ; for feeding or returning the slide-rest
to the commencing point; or for cutting right or left banded
screws The feed-screws are shown a little within the ways of
^ ^ ^^ the machine, and are turned by pinions into which me.^hes the
The depth" and form «;pur-wheel on the mandrel of the lathe-head. By the interven-
of the teeth are, of tion of suitable gearing, such a proportion is established be-
course regulated by j tween the rotation of the rod on which the screw is to be cut,
the shape of the cut- ' and the feed-screws themselves, as to obtain any required pitch
ting-tool of thread on the rod The rate of rotation of the rod being as-
In order to support sumed as permanent, an equal rate of the feed-screws will cut a
the axes on whi'-h the thread of a pitch equal to that of the feed-screws. If the latter
change-wheels re- are rotated at a slower rate, the pitch of the screw will be less;
volve a pedestal sup- if the feed-screws are rotated fester than the rod under treat-
ported by the hearers nient. the pitch of the screw on the lathe will be proportionately
or a bracket at the increased. See Bolt-cltter ; Rolt-tuR£HDING Machine; Tub-
lathe - head, is em- I eet-latse ; Scaew-corrLNG Lathe.
130
SCREW-DOCK.
2066
SCREW-HEAD SAW.
Screw- Cutting Lathe.
General Sir Samuel Bentham made machines forcutting wood-
Bcrews by means of rotary cutters.
In Royon'8 macliiue (Fig. 4?27), the die-chuck E is hollow,
and is turned by the hollow shaft B, rotated by a pinion mesh-
Fig. 4726.
Scre'w-down Cock. A cock provided with a
valve whicli is screwed down to its seat to prevent
tlie How of liquid, and raised more or less to permit
the passage of a determinate qnantity.
Screwr-dOTvii Valve. A valve whose stem has
a thread by which it may he screwed down to its
seat.
Screw-diiv'er. A tool for turning screws iu or
Fig. 4728.
Fig 4729.
Screw-Cutting Machine.
ing with the bevel-wheel C. The dies if iC are rotatable, have
Federal sets of threads adapted to screws of different sizes and
pitch, are secured within the chuck by screws Z., are caused to
approach or recede from each other by moving in the eccentric
plots i' i" upon turning the ring /, and are fixed at the proper
distance apart by a movement of the lever R. Tis the earri.ige
on which the screws or bolts are held between the jaws (" ('",
approached by a right and left hand screw. In tapping nuts,
the DUta are held by a hollow-ended mandrel inserted through
Screw-Driver.
Screw-Down Cock, out of their places. It has an
end like a blunt chisel, which en-
ters the jitci- in the screw-head.
In that shown (Fig. 4729), the handle is slotted to
receive pivoted blades of different sizes, which, ex-
cept the one in use, are turned hack within the
slot.
The screw-driver for taking apart and re-assembling
fire-arms is composed of two blades of steel, one of
which turns on a pivot, passing through the otlier,
or it may have an additional pivoted arm. The
longer arm has a perforation at one end fitting the
Screiv- Cutting Machine.
an opening in the chuck E. into the hollow shaft, while the tap
is gra.spcd by the jaws (" t'" of the carriage.
Screw-dock. (Hi/draulic Engineering.) A
contrivance for lifting a vessel out of the water, in
oriler thattlie bottom maybe examined and cleaned.
The vessel to be raised by this apparatus is floated over a
platform of wood, sunk to the depth of about 10 feet below the
surface of the water, and suspended from a strongly built wooden
framework by iron screws from 4i to 5 inches in diameter. This
platform has several shores on its surface, which are brought to
bear equally on the vessel's bottom, to prevent her from heeling
over on being raised out of the water. The platform is grad-
ually raided to the surface of the water, cnrrving the vessel
high and dry, suspended between the wooden frames.
Hullihen^s Screw-Forceps.
square of the "cone" or nipple, for the purpose of
unscrewing the nipple from its seat.
Scre'wr-for'ceps. (Surgical.) A dentist's in-
strument. Between the jaws Ls a screw which is
protruded into the nerve-canal, so as to fill it and
prevent the crushing of the tooth when the pressure
of the jaws comes upon it.
Screiv-gear. (^fachinfr!l.) The worm and
T-onn-irhfri, or endless screw and pinion.
Screw^-head Pile. A feather-edged file for
nicking screw-head.';.
Screw-head Saw. The saw for cutting nicks
in screw-heads is strength-
ened by a back-plate like
a tenon-saw.
In machine-made
screws for carpenter's use, Screw-Htad Saw.
SCEEW-HOOK.
2067
SCREW-MACHINE.
And known as vrood-scrcws, the nick is made by a
circular saw of small diameter.
Screv?-hook. (Surgical.) An instrument for
withdrawing foreign bodies from the ear or nostrils.
It has a shank with little S-shaped prongs at the
end. It is introduced into the opening and laid
alongside the object ; being then slightly rotated, the
hooks become engaged with the object, which is then
withdra\vn.
Screw^'ing-ma-chine'. A machine-tool for
cutting screws. See Sckew-machine ; Screw-
cutting Lathe, etc.
Scre'w'ing-ta'ble. A kind of screw-stock, used
for forming the threads of screw-bolts or wooden
screws.
Screw-jack. A li/ting-jack, in which the
power consists of a screw rotating in a nut in the
body of the tool. See J.\ck-scre\v.
a, screw-jack, with wooden case.
6, screw-jack, with malleable iron case.
c, windlass screw-jack, sinfrle purchase.
rf, windlass screw-jack, double purchase.
In these, additional power is obtained by multiplying gears
interposed between the lever and the nut which turns the screw.
e, tripod-jack.
/, bottle-jack.
"So termed from the form of the case. They are operated by
a removable lever inserted in the head.
It is by no means an uncommon thing for a house to be lifled
bodily from its site and removed by machinery to a new one,
without disturbing the inmates, but in Chicago the operation
was extended to almost the whole city, in 1867 - 68 The early
buildings were generally erected without any regard to the laws
Fig. 4732.
Fig. 4734.
ScTew-J(Kks.
of drainage, and eventually, as the city increased in siw, the
evil became intolerable. By means of screws acting under balks
of timber, one of the largest hotels, known as the Briggs House,
was raised in 27 diys to a hight of 4 feet 2 inches above its pre-
vious level. The building h.ad a frontage of 180 feet, a depth
of 80 feet, weighed 22.00<"t tons, and was 5 stories high, present-
ing accommodation for 4-50 guests, none of whom were disturbed
during the operation Tremont House, another hotel of a simi-
lar size, was also raised without accident The .screws employed
were about 2 feet long, 2i inches in diameter, with a pitch of
half an inch They worked in cast-iron sockets, and were
moved by handspikes ; 1,450 such screws and 600,000 cubic
feet of timber were used in nxising the Briggs House. A similar
plan was adopted in .Tuly, 1838, at Boston, when whole streets
of houses were raised in blocks of 6 houses together.
Screiw-key. A spanner for the articles which
socket upon the mandrel-screw.
The lever of a screw-press. A form
of key used with lock-faucets.
Screw - lock. (Locksmitliinq.)
This loi^k has various forms, and is
used for hand-cujfs, fillers, jnnnnc'cs,
and also as a padlock. The essen-
tial feature is an opening bar, which
is detained by a screw when in a
locked position.
Screw^-ma-chine'. (ilachinery.) A machine
for making from bar-iron screws and studs such
as are used in a machine-shop. It is of the na-
ture of a bolt-machine. The various sizes of dies
ScTtw-Madiine.
are stocked in the circular head, and such one
is presented to the blank, which rotates with the
mandrel of the head-stock, as may be of the sizif re-
quired. It has also a rest with a transversely sliding
tool-post, whereby a screw
may be cut off or dresseil.
The rest also affords a bearing
for a chasing-tool. The coun-
tershaft is shown dismounted
and placed upside down upon
the floor, resting u])on the
plates of the hangers.
2. (IVood-Screws.) A ma-
chine or series of machines
for shaving, nicking, and
threading screw-blanks. The
blanks are placed promiscu-
ously in a hopper and sorted
" and fed therefrom to the first
of the series of machines. The
blank falling into a socket or
being seized by a forceps, according to the mode of
feed adopted, is presented to the shaving-tool, and
Fig. 4735.
Fig. 47a3.
ScretD-Loci:
then dropped, to be again selected and fed to the
nicking-tool, the process being repeated to the threail-
SCREW-MOLDING.
2068
SCREW-PILE.
er ; or it is conducted through the consecutive oper-
ations.
Screvy-mold'iug. 1. A process of molding
screws in s.uid tor casting. In Fig. 4730', a plain
cylindrical mold is first made, and afterward the
Fig. 4737.
thread is formed by screwing a pattern-screw through
the mold.
2. A process of making sheet-metal screws for col-
lars or caps by pressure upon a former. See ScKEW-
CAP.
Screw-pile. A pile having a .screw-thread at its
lower end to enable it more readily to penetrate
hard ground and to hold it (irmly in position.
Screw-piles of small diameter are usually made of
wrought-iron and solid ; those of larger size are fre-
quently hollow and made of cast-iron.
They were invented by Mitchell, in England, and
are principally employed as foundations for light-
liouses, for beacons, and for mooring buoys.
They were used in the foundations of the Maplin
Sand Lighthouse at the mouth of the Thames, and
the Fleetwood Lighthouse, at Fleetwood, in Lanca-
shire, botli erected A. D. 1840.
a a a, mooring-pile,
6 6, mode of sinking the piles into position.
c c, piles for signal, mile, or telegrapli posts.
Mitchell'^ Screw-Pile,
ft ff, piles for tethering animals, or, on a larger scale, for at-
taching guvs or crnb moorings.
Fig. 473.S is a viuw of the screw-pile lighthouse on Thimble
Shoal, near the entrance to Hampton Roads. This was de-
signed by JIajor Peter C. Hains, to replace the light-vessel on
Willoughby Spit The shoal is of firm, hard, compact sand, and
the time employed in fixing the piles was rather less than two
months. The light is of the fourth order.
A mooring-pile 3 feet 6 inches in diameter gives a resisting
surface equal to 30 square feet, double that of a large anchor.
Fig. 4738.
u~fn
i J^O: IBDi . - SB "-!
^
Screw-Pile Lighthouse, Thimble Shoal, Hotnptnn Eoads, Virginia.
Thev nre nUn more dpeplv imbedded thnn the Utter, and thn«
ax^quire additional rp^istanco. Thev are screwed into ttir irmnnd
by vertical rods, and a lever above operated by men on barees.
A chain or buoy is attached to it.
Tbe shfifts of the east iron screw-piles nsed in the piers of
bridgres in the Ea.st Indies were c\ linders 1 inch tliirk, 3() inches
in external diameter, and in lengths of 9 feet. They were con-
nected by internal aanges and bolts. The lowest section formed
SCREW-PLATE.
2069
SCREW-PKESS.
the screw of the pile, having a thread 54 inches in diameter. I
The cylinders were cTentuallv filled with concrete. |
These piles were screwed into the ground by means of 4 levers, j
each 40 feet long, and having 8 bullocks joked to it. They j
penetrated from 20 to 45 feet.
Screw-plate. A steel plate having a series of ;
hollas of varying sizes, with worms and notches for
cutting threads.
It is usual to bore a smaller hole on each side of that in
which the screw is cut, and connect them with the latter by a
slit, forming angular cut ting -edges, which remove the metal, as
shown at a 6 c, Fig. 4739. The wire i.« commonly held by a
hand-vi:e in the left hand, and the plate operated with the
right hand, several holes, of gradually diminishing diameter,
Fis. 4739.
^^
Screw- Eates.
bein? emploved to produce the desired thread. In some cases,
for very short and small thread? the holes are merely threaded,
and not notched, as shown at rf. f is a folding device formerly
emp-ovel for cutting screw-thread^ ; the larger holes are near
the joint, so to allow greater holding power.
For screws exceeding i ,« iuch diameter, it is customary to use
a die-stock with movable dies ; several arrangements have been
adopted in these for holding and adjusting the dies ; in/ the
edges of the dies have triangular
notche= .«liding on corresponding
ribs In the opening of the stock,
and are held by one of the han-
dles when scre-ved in. The lower
figure has a pin on eich side,
which in one position fiLsa semi-
cylindrical groove in the die, so
as to hold it ; when rotated half
round, it presents a plain side to
the die, permitting its removal.
Screw-post. ( Sh ip-
wrijkliiig.) The inner
stern-post, or that through
which the shaft of the
screw-propeller passes.
Screvr-press. A press whose platen is operated
by a screw, in contradistinction to one which is
worked by a toggie, as in the Stanhope printing-
press ; by a wedge, as in some fonns of oil-presses ;
by hydraulic pressure, as in the flaxseed- press ; by
a lever, as in the primitive form of cheese-press. See
Fig. 1263.
The screw-press was used for coining in the reign
of Henry II. of France, being introduced by Brucher.
It was linally established in the French uiint, 1645.
1. Screw-presses are vertical or horizontal ; the
screw above or beneath the platen, which is usually
calletl a follower in this class of machinery. An
understanding of the matter will be as readily at-
tained by a few examples as by a labored description.
a. The old screw-press of the plantation or farm
\\.vX a vertical screw in the upper cross member of the
fnini'', and a follower which rose or fell, according to
the direction of motion of the sweep which rotated it.
b. In another form, the screw came up from below
and left the top of the box more clear for charging.
In the illustration shown, the screws G C are in du-
plicate and are actuated by the same gearing.
In Fig 4740, the follower D is attached to the smaller screw,
which works axially in the socket- thre;id of the larger screw.
The latter passes through the nut in the slidiog-framc. and is
stepped in a metallic block. The revolution of the lever causes
the hollow screw c' c' to rotate in the lower bar of the frame,
and thus lower or raise the box, according to the direction in
Fig. 4740.
Screw-Pre^s.
which the lever is moved. The threaded stem c at the same
time rotates in the sleeve-screw c', and raises or lowers the fol-
lower D. Thus the foUow-block and the press-box move fimul-
taneously and in opposite directions. See Balisg-peess ; Coin-
ing-press, etc.
e. Horizontal screw. In the example, the follower can be
operated by a slow or by a quick motion. The slow motion
arises from a hollow screw-spindle F which screws into a worm-
wheel G gearing with a worm. A rod E passing through said
screw-spiodle and connected with it by a key unites it with the
follower. The extreme end of the rod forms a toothed rack
which gears in a pinion rf : and if the key which unites said rod
with the screw-spindle is withdrawn, the pinion and rack form
the quick motion for the follower, which can be u^ed inde-
pendently of the slow motion.
Fig. 4741.
Jiorizonlal Srreic-Press,
The press has a slow, powerful motion when compacting the
bale : a quick retraction to free the bale and to open the cham-
ber for another charge.
Fig. 4742.
Screw and ToggU Press.
SCREW-PKESS.
2070
SCKEW-PROPELLER.
d Screw and toggle. Tho involution of the right and left
kaud screw drawa together the heads J and expands the togglea
K, forcing tuo followers toward the platens of the press.
e. hereto and lever. The lever id fconuected to the follower at
ODe end, and has u cylindrical nut ut the uther, which rocks in
l>eariQgs ut the other end of the lever, and is eug iged hy a bcreff
4743.
Screw and Liver Press.
which is stepped in the frame. The mule U hitched to the end
of the sweep, and aa he walks around, tiie out /climbs (or uinks)
on the screw H, tipping the lever A and depressing or raising
the follower Jin the box.
/. The rotating prtss. As the box rotates, the vertical screw
feed^ through its nut and depresses the follower. Kotation in
the other direction raises the follower.
Boohbindfr' s Screw-Press.
Rotary Screw- Press.
Chollet-Champion's screw-press (French) has three arbors to
which the crank can be applied, each producing a different
Telocity of movement in the platen. The upper two of these
are the axles of pinions which can be thrown into gear with a
Fig. 4745.
Chollet-Championys Screw-Press.
larger wheel c below them ; the third is the axle of this larger
and lowfr wheel itself. Upon the same arbor with this wheel
is a bevel-piuiou which engages a large hori^outal wheel / cor-
respondingly geared. The vertical arbor of thin horizontal
wheel carries a pinion which acts on an internal geuriug in the
last wheel d of the series, which is the nut applying the pOMcr
to the platen. The base of the construction larrying this ^\s-
teni of gearing is firmly secured to the platen, and the whole
apparatus rises and falls \Yith the movements of the press.
The smallest of the pinions to which the crank can be di-
rectly applied has 9 teeth, and the larger one 15. The wheel c
into which these pinions gear has 45 teeth. The bevel-pinion
has 10 teeth, and tiie bevel-wheel which it actuate342 tietli. Tho
pinion on the vertical axis of this whtel has again 10 teeth, and
the internal gearing 65 teeth. The length ol the crank is 13
inches, the diameter of the screw 4 inches, and the distance
between the threads about an inch.
The force is applied first directly to the large upper wheel d \
then by placing the crank on the ajiis of the lower vertical
wheel c, which, by the conical
gearing and the gearing of the Fig. 4746.
internal pinion and the wheel
(/, gives one turn to the nut of
the press for 27 turns of the
crank. For a greater power,
the crank is placed, as seen in
the cut, on the axis of the 15-
tooth pinion, «hich gives one
turn of the nut to 81 of the
crank. As the last resort, the
crank is transferred to the axis
«i of theU-tooth pinion, which
gives one turn of the nut to
l'SG\ of the crank. A pressure C
of 3'2 pounds on the 9-tooth
pinion is equal to 50 tons on
the surface of the body compressed.
2. A small stitching-press employed in attaching the head-
bands, etc., to books. It consists of two plain jaws, through
which guide-pins pass near each end ; their distance apart is
adjusted by means of a central screw See also Fly-prls» ;
iCoiNlNG, etc.
Scre^w-pro-pel'ler. A spiral blade on an axis
parallel with the keel of the vessel, and revolving
beneath tlie surface of the water, usually at the stern
of t!ie vessel.
Screws have been used at bow and stern ; at mid-
ships, over the keel, or alongside ; twin screws at
each side of the dead-wood at the stern.
In the early ajiplications of the screw as a jiro-
peller it consisted of a spiial blade, whiuh made one
convolution around its stem. Then two half-con-
volutions of a double-threaded screw were used.
Since that time the tendency has been to reduce the
length of the spiral.
We find notices of the suggested or experimental
fZ-^ "se of the screw-propeller by Hooke, 1680 ; Duqvu-t,
'-» 1727 ; Pancton, 1768 ; Watt, 1780 ; Seguin, 1792 ;
Fulton, 1794 ; Cartwright, 1798 ; Shorter, 1802.
The idea of propelling vessels by a screw in lieu
of oars is mentioned in the '* Machines et Inventions
approuvees par TAcademie Royale des Sciences de-
puis 1727 jusqu'a 1731."
Franklin suggested the same thing.
Lyttleton's English patent, in 1794, for an
"aquatic propeller " consisted of a screw of one, two,
or more threads wrapped around a cylinder, and re-
volving in a frame placed at the head, stern, or side
of a vessel.
The credit of the first application of the screw-pro-
peller for marine propulsion is undoubtedly due to
Colonel John Stevens, of Hoboken, N. J. In 1804, he
constructed a boat with twin screws, which ^'attained
a very considerable speed." The machinery of this
boat {ii, Fig. 47-17), which was 50 feet in length, is
still preserved in the Stevens Institute of Tech-
nology at Hoboken. The boat itself is shown at b.
In 1844, this machinery was placed in a vessel
modeled on the lines of the fir.st boat, wliich, in the
presence of a committee of the American Institute,
it propelled at the rate of 8 miles an hour.
In 1806, he built a second and larger boat called
the "Fhcenix," with which he made a successful trip
SCREW-PROPELLER.
2071
SCREW-PROPELLER.
rig. 4747.
ton," was built by the Lairds of Birkenhead, and
launched July 7, 1838. This vessel was built for
Captain Stockton, of the United States Navy. She
crossed to the United States in 1839, and was pur-
chased by the Delaware and Raritan Canal Com-
pany. Captain Ericsson subsequently built tlie
propeller "Enterprize." He was the hrst to couple
Fig. 4748
Stevens's Propeller, 1804.
to Albany in August, 1807, but a few days after that
of Fulton, in the "Clermont." This, in which a
single screw was employed, is shown at c.
Stevens navigated his proi)eller by sea to the Dela-
ware, as Chancellor Livingston had obtained a pat-
ent for the navigation of the Hudson by steam. See
Pkopeller.
F. P. Smith, a farmer, of Romney, England, made
a model boat in 1834, in which was a stern screw-
propeller driven by a spring. Smith's patent was
granted May 31, 1836. Though his claims were
more extensive, the actual novelty of his invention
seems to have been placing the screw in an open
space in the dead-wood (see Fig. 3973). He con-
structed a boat of 10 tons burden, with an engine of
6 horse-power, which was tried on the Paddington
Canal, the river Thames, and, the next year, along
the coast.
The "Archimedes" was constructed by the help
of the Messrs. Rennie, in 1838. She was 155 feet
long, 237 tons burden, 90 horse-power. The screws
were 5 and 7 feet in diameter, the lengths 7 J and 8
feet.
In 1842, the " Rattler " was built, to determine
the best proportions of the screw, and the " Alecto"
was built on the same lines, and with paddle-wheels,
to compare the modes of propulsion. The propeller
was preferred, and soon had an important place in
the British navy.
Captain John Ericsson's English patent is dated
July 13, 1836, for a propeller containing several
blades or segments of a screw, the twist of which
was determined in accordance with the principle now
usually adopted. His propeller, the " Francis B.
Ogden," was tried in April, 1837, and in May of
that year was used in towing an American packet,
the ship " Toi'onto," of 700 tons burden, to sea ; 4J
knots an hour against wind and tide.
Ericsson's second vessel, the " Robert F. Stock-
Screw-Propellers.
the engine directly to the propeller-shaft. " It will
thus be seen that Captain Ericsson accomplished for
the screw-propeller in America and in England what
Fulton did for the paddle-wheel in the former and
Bell in the latter country, namely, its practical in-
troduction." — WOODCROFT.
Several years before screw-propulsion had assumed
any commercial importance in England, the carrying-
trade on our lakes was, to a great extent, conducted
by screw-vessels. Already, in 1843, the Ericsson
SCREW-PROPELLER
2072 SCREW-PROPELLER STEAM-ENGINE.
line of screw -steamers was iu full operation between
Philadelphia and Haltimore, running through the
Delaware and Chesaiieako Canal.
Keiinie proposed to make the screw spiral instead
of helical ; the form being generated by winding an
inclined plane around a cone or spire. This pro-
peller had two blades on a cylindrical hub, and
strikingly resembled a shark's tail {a, Fig. 4748).
b shows Hancock's two-bladed screw. The blades
are removable.
Bourne prefers three-bladed screws, and gives the following
data : —
The area of the circle described by the extremities of the
blade.< should have one squire foot for every 2.^
equire feet in the area of the immersed midship-
RectioQ. The pitch of the screw should be equal
to or a little exceeJins the diameter, and should _
have about * gof a convolution. The pitch should
increase gradually toward the leading end of the
screw, and the pitch of the center be 10 per rent