The most common gauge, often called the "marking gauge", marks (or, more correctly, "scribes") a line parallel to the edge of a workpiece.
Commercial marking gauges -- usually of beech-wood -- consist of two parts, a fence about 27 x 2 in and a stem about 9–10 in long, sometimes graduated, and carrying a pointed steel spur at one end. The head is fixed in any required position by means of a wood thumbscrew or by wedge.
The term "gauge", itself -- used as both noun and verb, and pronounced "gaj" -- dates to 1440, in Promptorium Parvulorum, the first English-Latin dictionary. (See page 424 of The Barnhart Dictionary of Etymology, 1988). As verb, "to gauge" means to measure accurately. As a noun, if we follow Barnhart, the term itself is "borrowed through Anglo-French gauge, from Old North French gauger, from gauge, or gauging rod, perhaps from Gallo-Romance galga, collective plural of Frankish galgo...."
As spelling variants, examples of both "gauge" and "gage" exist from Middle English, "though in American English, "gage is used exclusively in some technical uses and especially in technical uses of the verb" Barnhart, page 424.
Very ancient tools, marking gauges are of two types: Some marking gauges have sixteenth-inch graduations along the beam, while others are unmarked and require setting with a rule. The "unmarked" type is shown in the jpg on the left. On the right is a crude drawing of a person using a gauge to mark a line parallel to an edge. Below, in the box for Shelley, is an image from Chelsea Fraser, The Boy's Busy Book New York: Thomas Y Crowell, 1927, page 48.
Tradesmen and apprentices often made their own.... Marking Gauges which may still be seen in the work-shops in a great variety of patterns, some of which are both ingenious and beautiful. The home-made method of fixing the fence is almost invariably by captive wedge....
Source: R A Salman, Dictionary of Woodworking tools c 1700-1970, and tools of allied trades 2d ed. London: Allen and Unwin, 1989, pages 201-202
The following are references in the online Oxford English Dictionary (subscription):
Of the Gage..Its Office is to Gage a Line parallel to any straight side.
Source: 1678 J. Moxon, Mechanick Exercises. London, 1683 I. page 90;
Gage, in joinery..is made of an oval piece of wood, fitted upon a square stick, to slide up and down stifly thereon [etc.].
Source: 1751 Ephraim Chambers Cyclopaedia, London. [First published 1738.]
The gauge is an instrument used for drawing or making a line on a piece of stuff to a width parallel to the edge.
Source: Joseph Gwilt, An encyclopædia of architecture, historical, theoretical, and practical 1842 (1859)
From this flat surface the desired thickness must be set off at each end with a marking gauge .... the scratch which it leaves indicating the amount to be planed off the opposite side.
Source: Shelley, C. P. B. (Charles Percy Bysshe), Workshop appliances including descriptions of the gauging and measuring instruments, the hand cutting-tools, lathes, drilling, planning, and other machine-tools used by engineers. by C. P. B. Shelley New York,: D. Appleton & co., 1873, pages 122-123
The following account is adapted from Goodman, 1966, and Salaman, 1989:
No evidence suggests that the Egyptians, the Greeks or the Romans used this tool. Our first known record of its use comes from an engraving c. 1600 by the engraver, Hieronymus Wierix: Holy Family. (At this time -- 6-1-07 -- no evidence exists that this image in on the internet.) There was apparently no method of fixing the adjustable fence (Goodman, 1966, page 201; Salaman, 1989, page 202).
Later, long, narrow wedges are used to secure the fence, as Denis Diderot, in his Encyclopédie ,1763, illustrates. As Salaman points out, these wedges pass "vertically through the depth of the head, a method which is still used in modern French Gauges". The earliest known use of the thumbscrew -- the current standard for factory-made gauges -- is in Joseph Smith, Explanation or key, to the various manufactories of Sheffield, with engravings of each article South Burlington, Vt. : Early American Industries Association, 1816.This became the standard method for most commercially made English Marking Gauges.
Early eighteenth-century Marking Gauges do not always have a spur. Instead the workman held a spike or pencil against the end of the stem, as is done today with a Thumb Gauge.
Source: R A Salman, Dictionary of Woodworking tools c 1700-1970, and tools of allied trades 2d ed. London: Allen and Unwin, 1989. pages 201-202
The 15th-century poem "The Debate of the Carpenter's Tools" (Hazlitt, Early Popular Poetry, Vol. 1, pp. 79–90) mentions a 'skantyllyon', which may have been some kind of gauge, but no examples of the tool occur in the medieval pictures. Felibien [A. Felbien, Principes de l'Architecture, 1676, has two gauges, the ordinary marking gauge and one with an extra long point, probably a cutting gauge. Neither of these tools show any fixing for the fence, and the printer, J. Moxon, Mechanick Exercises. 1683, states that "the Oval, as he calls the block, is 'fitted stiff upon the staff'." Peter Nicholson, Mechanical Exercises, 1812, shows a perfectly plain gauge similar to this, with no provision for securing the block, but Diderot, in his Encyclopédie , "trusquin" (French for marking gauge) has a thin, narrow wedge, while Bergeron's of 1816 has a small screw. Nicholson in his text mentions that separate gauges must be set when marking mortise and tenon joints, but on the Continent over a century earlier, a "double gauge" was in common use.
Marking Gauge included in this inlaid panel on Danish tool chest, 1679, Dansk Folkmuseum, Copenhagen.
Source: W L Goodman, The History of Woodworking Tools, London: Bell, 1966, page 201
Sources: A. Felbien,
Principes de l'Architecture, etc.
Paris, 1676; J. Moxon, Mechanick
Exercises. London, 1683;
Paris, 1765 [online but subscription needed];
P Nicholson, Mechanical Exercises.
London, 1812; Joseph Smith, Explanation or key, to the various manufactories
of Sheffield, with engravings of each article,
South Burlington, Vt. : Early American
Industries Association, 1975, 1816;
Shelley, C. P. B. (Charles Percy Bysshe), 1827-1890, Workshop appliances including descriptions of the gauging and measuring instruments, the hand cutting-tools, lathes, drilling, planning, and other machine-tools used by engineers. by C. P. B. Shelley New York,: D. Appleton & co., 1873. (Making of America Books)
Chelsea Fraser, The Boy's Busy Book New York: Thomas Y Croweel, 1927; Ediwn G Hamilton, Home Carpentry New York: Dodd Mead, 1941, pages 18-19; W L Goodman, The History of Woodworking Tools, London: Bell, 1966
Robert K Barnhart, ed., The Barnhart Dictionary of Etymology New York: H W Wilson, 1988