Dovetoil-hal to Draw filing.

Dovetail-halved joint. (Woodwk.) A halved joint in which both cuts are narrowed at the heel as in a dove­tai l.
Dovetailing. (Furn.) Fastening to-,gether by means of dovetailed joints. (Print.) When doubli,ng up leads the arrangement ~f them so that they overlap or break joints.
Dovetail lap joint. (Woodwk.) Same as dovetail-halved joint.
Dovetail saw. (Woodwk.)A saw simi­lar to a hacksaw but somewhat smaller, with finer teeth and usually with different shape handle.
Dovetail tongue. (Wood Patmkg.) It is sometimes necessary to permit a part of a pattern to remain in the sand until after the withdrawal of the body of the pattern. This is ac­complished with a dove-tail tongue, a piece held in place by its beveled edges. The p!inciple is similar to that of the steel slide which covers the shuttle in a sewing mahcine.
Dowel. A wood or metal pin used by patternmakers to keep portions of patterns in position during molding. Also used in making permanent joints.
Doweling. (Furn.) The making of joints by the aid of dowels. Fre­quently butt joints are made secure by glue and dowel pins.
Dowel pin. (Wood Patmkg.) Wood or metal pin used for keeping two parts of a core box in proper relation, or for keping the parts of a pattern in position during the ramming' up.
Dowel screw. (Furn.) A wood screw threaded at both ends.
Downdraft carburetor. (Auto.) A carburetor in which the air enter at the top and travels downward past the spray nozzle.
Downspout. (Arch.) A pipe or con­ductor for carrying rain water from' a roof to the ground or to a sewer connection.
Downwash. (Aero.) The air deflected perpendicular to the direction of motion of an airfoil.
Downwash angle. (Aero.) The angle through which the lifting surfaces of an airplane deflect the airs,tream.
Drachm. Same as dram. (SEE APOTH­ ECARIES FLUID MEASURE.)
Draft. (Fdry. and Wood Patmkg.) The taper on a pattern that makes pos­sible its easy removal from the sand.
Drafting. The art of drawing:
Draftsman. One who prepares drawings, or portrays graphically; usu­ally applied to one who uses me" chanical aid or instruments in his work.
Draftsman's scale. (Draw.) The tri­angular or flat measuring scale used by the draftsman. Usually made of
boxwood with one edge graduated in 16ths, 118, 114, 1/2 etc., as on a standard scale. Other edges are
divided into fractional parts thereof to facilitate drawing at a reduced scale.
Draft stop or fire stop. (B.ldg.) Ob­structions placed in air passages

Drag. (Aero.) A retarding force acting upon a body in motion through a fluid, parallel to the direction of motion of the body. It is a compo­nent of the total fluid forces acting on .the body. (Fdry.) The bottom section of a founder's molding box or flask.
Drag link. (Auto.) The rod which con­nects the left steering-knuckle arm with the steering-gear arm. There are two cups and a spring at each end to engage the ball ends of these arms.
Dragon's blood. (Paint.) A resinous substance obtained from a species of palm growing in Siam, odour­less, tasteless, insoluble in water, but soluble in alcohol and ether; forms a red solution; used in the colouring of varnish and other sub­stances, and in photo-engraving.
Drag rope. (Aero.)A long rope which can be hung overboard from a bal­loon so as to act as a brake and a variable ballast when making a land­ing.
Drag strut. (Aero.) A fore-and-aft compression member of the inter­nal bracing system of a wing.
Drag wire. (Aero.) A wire intended primarily to resist the forces acting backward in the chord direciton. It is &enerally enclosed in the wing.
Drain. A pipe, channel, or trench through which waste water or other liquid is carried off as to a sewer.
Drainage. (Plumb.) A system of drains; the act or means of drain­ing. That which is drained off, as waste water.
Drain cock. (Plumb.) A small valve placed at a low point in a line of piping to permit draining.
Draintile. Hollow, tile, such as sewertile, used for draining wet places.
Dram. (Avoirdupois weight) On six­ teenth of an ounce.
Draw. (I) To portray by a system of lines. (2) To bring the temper of steel from extreme hardness to the desired hardness or temper. (3) To form by a stretching or distorting process; as to draw out wire.
Drawbar. (Auto.) A bar with an eye at each end used as a tow bar. The name also is applied to other de­vices used for the same purpose.
Draw' bolt. The ordinary bolt, such as is used for fastening doors.
Draw chisel (Mach.) A pointed cold chisel used for shifting the center for the hole to be drilled, in cases where the drilling has been started but the drill has run, i.e., not drill­ing in the exact position desired.
Draw chuck. (Mach.) Used on small accurate work. It operates by a lon­gitudinal motion in a taper bear­mg.
Draw-cut shapero (Mach.) A shaper which cuts with a pull stroke rather than the usual push stroke.
Drawer pull. The handle or other attachment on the front of a drawer so that it may be readily opened.
Drawer slip. (Cabwk.) One of the guides or strips on which a drawer moves. .
Draw filing. (Metalwk.) A metal