screw 
equal parts, with the screw-threads removed from alter- 
nate sectors, used to form the closure of a breech-loading 
cannon. In some eases the interruptions extend entirely 
around the screw, so that, in the common parlance of 
mechanics, "every other thread " is removed. Such a 
screw will turn perfectly in a nut of sufficient length. 
See cut under cannon. Involution Of six screws. See 
invalidity. Left-handed screw, a screw which is ad- 
vanced by turning from right to left, in contradistinction 
to the usual or riyht-handed screw, which turns in the 
opposite direction. Male screw. See male*. Metric 
screw, a screw in which the pitch is commensurable in 
units or fractions of a unit of the French metric system. 
Milled screw, a screw with a flat broad head the edge 
of which is fluted, crenated, or roughened, to afford a 
firm hold for the fingers. Such screws are much used in 
chemical, philosophical, and electrical instruments, and 
in small machines. Perpetual screw. Same as endless 
screw (which see, under endless). Plane screw. See 
planei. Portland screw, the cast of the interior of 
a fossil shell, Ceriltiium portlandicum. See screwstone. 
Principal screw of inertia. See inertia. Quadruple 
screw, a screw with four consecutive threads, all of the 
same pitch. Reciprocal screws. See reciprocal. Reg- 
ulating screw, a screw used to determine a motion ; a 
screw which guides the slides and moving parts of ma- 
chinery. Riggers' screw. See rigger. Right-and-left 
screw, a screw of which the threads upon the opposite 
ends run in different directions. See cuts under compound 
and lathe. Screw propeller, a propeller acting on the 
principle of the screw, attached to the exterior end of a 
shaft protruding through the hull of a vessel at the stern. 
It consists of a number of spiral metal blades either cast 
together in one piece or bolted to a hub. In some special 
cases, as in ferry-boats, there are two screws, one at each 
end of the vessel. In some war-vessels transverse shafts 
with small propellers have been used to assist in turn- 
ing quickly. An arrangement of screws now common is 
the twin-screw system, in which two screws are arranged 
at the stern, each on one of two parallel shafts, which are 
driven by power independently one of the other. By stop- 
ping or Blowing up one shaft while the other maintains its 
Screw Propeller. 
A, sectional elevation, the section being through shaft and huh, 
showing method of attaching blades ft by Dolts i; S, side elevation ; 
C, cross-section of blade, on larger scale ; D, diagrammatic view of 
hull of a screw-propeller ship, in which k shows position of boilers; 
/, the engines ; f, propeller-shaft ; f, thrust-block ; g, propeller. 
velocity, very rapid turning can be effected by twin screws, 
which have, moreover, the advantage that, one being dis- 
abled, the vessel can still make headway with the other. 
Some vessels designed to attain high speed have been 
constructed with three screws. A very great variety of 
forms have been proposed for screw-propeller blades ; but 
the principle of the original true screw is still in use. Vari- 
ations in pitch and modifications of the form of the blades 
have been adopted with success by individual construc- 
tors. The actual area of the screw propeller is measured 
on a plane perpendicular to the direction in which the 
ship moves. The outline of the screw projected on that 
plane is the actual area, but the effective area is, in 
good examples, from 0.2 to 0.4 greater than this; and 
it is the effective area and the mean velocity with which 
the water is thrown astern that determine the mass 
thrown backward. The mass thrown backward and the 
velocity with which it is so projected determine the pro- 
pelling power. A kind of feathering propeller has also 
been used, but has not been generally approved. Com- 
pare feathering-Herd?. See also cut under banjo-frame. 
Screw surface, a heiicoid. Setting-up screw, a screw 
for taking up space caused by wear in journal-boxes, etc. ; 
an adjusting-screw. Society screw, a screw by which 
an objective is attached to the tube of a microscope, of a 
standard size adopted (in 1857) by the Royal Microscopical 
Society of London and now almost universally used. 
Spiral screw, a screw formed upon a conical or conoidal 
core. Transport screw, a screw working in ^trough or 
passage for transferring grain or other granular or pul- 
verulent material. Compare convener. Triple screw, 
a screw having three consecutive threads, all of the same 
pitch. Under the screw, subjected to or influenced by 
strong pressure; compelled:; coerced. Variable screw, 
in lathes and other machines, a feed-screw which by the 
varying velocity of its rotation gives a variable feed. 
V-threaded screw, a screw having a thread of trian- 
gular cross-section. See diagram of screw-threads under 
screw -thread. Winged screw, a screw with a broad flat- 
tened head projecting in a line with its axis so as to be 
conveniently grasped by the ends of the fingers for turn- 
ing it. (See also lead-screw, leveling-screie, micrometer- 
screw, thumb-screw, wood-screw.) 
screw 1 (skro), v. [Formerly also scrue; = D. 
Ki-liroeren_ = MLG. schruven = G. schrauben = 
Icel. skrufa = Sw. xkrufra = Dan. skrue, screw; 
from the noun.] I. trans. 1. To turn, move, 
tighten, fasten, press, or make firm by a screw, 
or by giving a turn to a screw ; apply a screw 
to, for the purpose of turning, moving, tighten- 
ing, fastening, or pressing: as, to screw up a 
bracket ; to screw a lock on a door ; to screw a 
press. 
5421 
Screw up the heighten'd pegs 
Of thy sublime Theorbo four notes high'r. 
Quarter, Emblems, i., Invoc. 
2. To turn or cause to turn, as if by the appli- 
cation of a screw; twist. 3. To force; espe- 
cially, to force by the application of pressure 
similar to that exerted by the advancing action 
or motion of a screw; squeeze: sometimes with 
up or out: as, to screw up one's courage. 
We fail ! 
But screw your courage to the sticking-place, 
And we'll not fail. Shak., Macbeth, i. 7. 60. 
Fear not, man ; 
For, though the wars fail, we shall screw ourselves 
Into some course of life yet. 
Beau, and Fl., Captain, it 1. 
He ecrued up his poore old father in law's accounte to 
above 200 1 ''. and brought it on y generall accounte. 
Bradford, Plymouth Plantation, p. 289. 
4. To press hard upon; oppress as by exac- 
tions or vexatious restrictions or conditions. 
Our country landlords, by unmeasurable screwing and 
racking their tenants, have already reduced the miserable 
people to a worse condition than the peasants in France. 
Swift. 
In the presence of that board he was provoked to ex- 
claim that in no part of the world, not even in Turkey, 
were the merchants so screwed and wrung as in England. 
Hallam. (Imp. Diet.) 
5. To twist; contort; distort; turn so as to 
distort. 
Screw your face at one side thus, and protest. 
B. Jonson, Every Man out of his Humour, v. 1. 
The self-important man in the cocked hat . . . screwed 
down the corners of his mouth, and shook his head. 
Irving, Sketch-Book, p. 63. 
II. intrans. 1 . To turn so as to serve for tight- 
ening, fastening, etc. : as, a nut that screws to 
the right or to the left. 2. To have or assume 
a spiral or twisting motion : as, the ball screwed 
to the left. 3. To move or advance by means 
of a screw propeller. [Rare.] 
Screwing up against the very muddy boiling current. 
W. H. Russell, Diary in India, vii. 
4. To require students to work hard, or sub- 
ject them to strict examination. 
screw 2 (skro), n. [< ME. screwe, assibilated 
shrewe, mod. E. shrew : see sftrew 1 .] 1. A stingy 
fellow ; a close or penurious person ; one who 
makes a sharp bargain ; an extortioner ; a miser ; 
a skinflint. 
The ostentatious said he was a screw; but he gave away 
more money than far more extravagant people. 
Thackeray, Newcomes, viii. 
2. A vicious, unsound, or broken-down horse. 
Along the middle of the street the main business was 
horse-dealing, and a gypsy hostler would trot out a suc- 
cession of the weediest old screws that ever kept out of 
the kennela Harper's Mag., LXXVI. 625. 
What screws they rode ! 
Lawrence, Guy Livingstone, 111. 
screwable (skro'a-bl), a. Capable of being 
screwed : as, a screwable bracket. The Engi- 
neer, LXIX. 411. 
screw-alley (skro'al"i), . In a screw steam- 
er, a passageway along the shaft as far aft as 
the stern tubing, affording an opportunity for 
thorough examination of the shaft and its bear- 
ings : known in the United States as shaft- 
alky. Also shaft-tunnel. [Eng.] 
screw-auger (skro'a"ger), n. See auger, 1. 
screw-bean (skro'ben), w. The screw-pod mes- 
quit; also, one of its pods. See mesqitift, Pro- 
sopis. 
screw-bell (skro'bel), . An instrument re- 
sembling a bell in shape, with a screw-thread 
cut on the interior surface : used for recovering 
lost tools in a bore-hole. 
screw-blank (skro'blangk), n. Apiece of metal 
cut from a bar preparatory to forming it into a 
screw. 
Screw-bolt (skro'bolt), n. A square or cylin- 
drical piece of iron, with a knob or flat head at 
one end and a screw at the other, it is adapted 
to pass through holes made for its reception in two or 
more pieces of timber, metal, etc., to fasten them together 
by means of a nut screwed on the end that is opposite to 
the knob or head. See cuts under bolt and screw. 
screw-box (skro'boks), n. A device for cutting 
the external threads on wooden screws, simi- 
lar in construction and operation to the screw- 
plate. 
screw-burner (skro'ber"ner), n. In lamps : (a) 
A burner having a screw to raise and lower the 
wick. (6) A burner which is attached by a 
screw-thread to the socket of the lamp-top. 
K. H. Knight. 
Sprew-caliper (skr6'kal"i-per), . A caliper 
in which the adjustment of the points is made 
by a screw. E. H. Knii/lit. 
screw-feed 
screw-cap (skro'kap), n. A cover to protect 
or conceal the head of a screw, or a cap or cover 
fitted with a screw. 
screw-clamp (skro'klamp), n. A clamp which 
acts by means of a screw. 
screw-collar (skro'kol"ar), n. In microscopy, 
a device for ad justing the distance between the 
lenses of an objective so as to maintain defini- 
tion with varying thickness of the cover-glass. 
Jour. Roy. Micros. Soc., 2d ser., VI. ii. 317. 
screw-coupling (skro'kup'ling), n. A device, 
in the form of a collar with an internal screw- 
thread at each end, for joining the ends of two 
vertical rods or chains and giving them any 
desired degree of tension ; a screw-socket for 
uniting pipes or rods. 
SCrew-CUt (skro'kut), n. A cut made in a spiral 
direction; specifically, a spiral cut in the tip 
of horn to form a plate which, pressed out flat, 
may be used for comb-making. 
screw-cutter (skro'kuf'er), n. 1. A hand- 
tool or die for cutting screws. It consists of a re- 
volvable head (into which the material to be operated on 
is inserted), to the interior of which cutters, adjustable by 
screws from the outside, are attached radially. 
2. A screw-cutting machine, or one of the cut- 
ting-tools used in such a machine. 
screw-cutting (skro'kuf'ing), u. Used in cut- 
ting screws Screw-cutting chuck. See chuck*. 
Screw-cutting die, the cutting-tool in a screw-cutting 
machine; a screw-plate. E. H. Knight. Screw-cut- 
ting gage, a gage with angles, by which the inclination 
oftne point of the screw-cutting tool can be regulated, as 
well as the inclination of the tool itself, when placed in 
position for cutting the thread. E. H. Knight. See cut 
under center-gage. Screw-cutting lathe, (a) A lathe 
with a slide-rest, with change-gears by which screws of 
different pitch may be cut. (b) Same as screw-cutting 
machine. Screw-cutting machine, a form of lathe for 
cutting screw-threads upon rods. The rod is caused to 
rotate against a cutting-tool while being thrust forward at 
a fixed rate. The pitch of the screw is determined by the 
relative speeds of rotation and advance of the bar, which 
are controlled by suitable gearing ; and the size and depth 
of the thread are controlled by the cutting-tool employed. 
Also called screw-cutting lathe. 
Screw-die (skro'di), n. A die used for cutting 
screw-threads. 
Screw-dock (skro'dok), . A kind of graving- 
dock furnished with large screws to assist in 
raising and lowering vessels. 
Screw-dog (skrO'dog), n. In a lathe, etc., a 
clamp, adjustable by means of a screw, for 
holding the stuff securely in the carriage. 
Screw-dollar (skro'doFiir), n. A medallion of 
which the obverse and reverse are in separate 
plaques which can be screwed together so as 
to form a very small box. Also called screw- 
medal. 
screw-driver (skr6'drl"ver), n. A tool, in 
form like a blunt chisel, which fits into the nick 
in the head of a screw, and is used to turn the 
screw, in order to cause it to enter its place or 
to withdraw it. 
screwed (skrod), p. a. [Pp. of screw 1 , v.~] 
"Tight"; intoxicated; drunk. [Slang.] 
Alone it stood, while its fellows lay strew'd, 
Like a four-bottle man in a company screw'd, 
Not flrm on his legs, but by no means subdued. 
Barham, Ingoldsby Legends, I. 161. 
She walked so unsteadily as to attract the compassion- 
ate regards of divers kind-hearted boys, who . . . bade 
her be of good cheer, for she was "only a little screwed." 
Dickens, Martin Chuzzlewit, xxv. 
screwed-work (skrod'werk), n. In wood-lttrn- 
ing, work in which the cutting is done in a 
spiral direction, so as to leave a spiral fillet, 
bead, or other ornamental spiral pattern upon 
the finished article, as in balusters, etc. 
Chestnut or sycamore is far more suitable for the pro- 
duction of screwed-work. Campin, Hand-turning, p. 257. 
screw-elevator (skro'el"e-ya-tqr). n. 1. A 
form of passenger-elevator in wnicn the cage is 
lifted by a screw. 2. A dentists' tool, con- 
sisting of a staff having a gimlet-screw on the 
end to screw into the root of a tooth in order 
to pull it out. 3. In surg., a conical screw of 
hard rubber used to force open the jaws of 
maniacs or persons suffering from lockjaw. 
E. H.Kmylit. 
screwer (skrii'er), . [< screw*, r>j + -erl.] 
One who or that which screws. 
screw-eye (skro'i), . 1. A screw having a 
loop or eye for its head : a form much used to 
furnish a means of fastening, as by a hook, a 
cord, etc. 2. A long screw with a handle, 
used in theaters by stage-carpenters in secur- 
ing scenos. 
screw-feed (skro'fed), n. 1. The feeding-mech- 
anism actuating the lead-screw of a lathe. 
2. Any feed-mechanism governed or operated 
by a screw. 
