What is "geometric lathe"

Geometric \Ge`o*met"ric\, Geometrical \Ge`o*met"ric*al\, a. [L. geometricus; Gr. ?: cf. F. g['e]om['e]trique.]

1. Pertaining to, or according to the rules or principles of, geometry; determined by geometry; as, a geometrical solution of a problem.

2. (Art) characterized by simple geometric forms in design and decoration; as, a buffalo hide painted with red and black geometrical designs.

   Syn: geometric.

   Note: Geometric is often used, as opposed to algebraic, to include processes or solutions in which the propositions or principles of geometry are made use of rather than those of algebr

   1. Note: Geometrical is often used in a limited or strictly technical sense, as opposed to mechanical; thus, a construction or solution is geometrical which can be made by ruler and compasses, i. e., by means of right lines and circles. Every construction or solution which requires any other curve, or such motion of a line or circle as would generate any other curve, is not geometrical, but mechanical. By another distinction, a geometrical solution is one obtained by the rules of geometry, or processes of analysis, and hence is exact; while a mechanical solution is one obtained by trial, by actual measurements, with instruments, etc., and is only approximate and empirical.

      Geometrical curve. Same as Algebraic curve; -- so called because their different points may be constructed by the operations of elementary geometry.

      Geometric lathe, an instrument for engraving bank notes, etc., with complicated patterns of interlacing lines; -- called also cycloidal engine.

      Geometrical pace, a measure of five feet.

      Geometric pen, an instrument for drawing geometric curves, in which the movements of a pen or pencil attached to a revolving arm of adjustable length may be indefinitely varied by changing the toothed wheels which give motion to the arm.

      Geometrical plane (Persp.), the same as Ground plane .

      Geometrical progression, proportion, ratio. See under Progression, Proportion and Ratio.

      Geometrical radius, in gearing, the radius of the pitch circle of a cogwheel.
      --Knight.

      Geometric spider (Zo["o]l.), one of many species of spiders, which spin a geometrical we

   2. They mostly belong to Epeira and allied genera, as the garden spider. See Garden spider.

      Geometric square, a portable instrument in the form of a square frame for ascertaining distances and heights by measuring angles.

      Geometrical staircase, one in which the stairs are supported by the wall at one end only.

      Geometrical tracery, in architecture and decoration, tracery arranged in geometrical figures.

Lathe \Lathe\ (l[=a][th]), n. [OE. lathe a granary; akin to G. lade a chest, Icel. hla[eth]a a storehouse, barn; but cf. also Icel. l["o][eth] a smith's lathe. Senses 2 and 3 are perh. of the same origin as lathe a granary, the original meaning being, a frame to hold something. If so, the word is from an older form of E. lade to load. See Lade to load.]

1. A granary; a barn. [Obs.]
   --Chaucer.

2. (Mach.) A machine for turning, that is, for shaping articles of wood, metal, or other material, by causing them to revolve while acted upon by a cutting tool.

3. The movable swing frame of a loom, carrying the reed for separating the warp threads and beating up the weft; -- called also lay and batten.

   Blanchard lathe, a lathe for turning irregular forms after a given pattern, as lasts, gunstocks, and the like.

   Drill lathe, or Speed lathe, a small lathe which, from its high speed, is adapted for drilling; a hand lathe.

   Engine lathe, a turning lathe in which the cutting tool has an automatic feed; -- used chiefly for turning and boring metals, cutting screws, etc.

   Foot lathe, a lathe which is driven by a treadle worked by the foot.

   Geometric lathe. See under Geometric

   Hand lathe, a lathe operated by hand; a power turning lathe without an automatic feed for the tool.

   Slide lathe, an engine lathe.

   Throw lathe, a small lathe worked by one hand, while the cutting tool is held in the other.

A geometric lathe was used for making ornamental patterns on the plates used in printing bank notes and postage stamps. It is sometimes called a guilloché lathe. It was developed early in the nineteenth century when efforts were introduced to combat forgery, and is an adaptation of an ornamental turning lathe. The lathe was able to generate intersecting and interlacing patterns of fine lines in various shapes, which were almost impossible to forge by hand-engraving. They were used by many national mints.