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This section includes set squares in a variety of materials, T squares, adjustable set squares, marquois triangles, clinographs and isographs.
A quality, 45 degree, framed set square in mahogany with a bevelled ebony edge. The square was made by W F Stanley and is held together with fine loose tenons and brass pins. This set square would date from circa 1900.
A variety of set squares. The large 60 degree one is made of celluloid and was retailed by the Scholastic company of Bristol. The small 60 degree one is made of vulcanite (hard vulcanised rubber invented in the mid-nineteenth century). It belongs to a Harling 'Woolwich Pattern' set of drawing instruments and is probably late 19th century. The 45 degree set square is made of plated steel and has inch scales on two edges. It probably came from a school set and is early twentieth century.
A pair of small set squares from a French set of drawing instruments by Aphe Cousin & Cie of Paris. Probably made of pear wood, the 45 degree one is signed "JFA Paris". They date from about 1900.
Plated steel and celluloid 30 degree set squares from school sets.
A set of boxwood Marquois scales from a Harling Woolwich pattern set of drawing instruments, c1900. These scales were included in both Woolwich and Sandhurst cases and were used for military purposes. The special triangle has a ratio of 3 between the lengths of the hypotenuse and the shortest side.
A six inch isograph by W F Stanley of London, made of boxwood and brass with a steel leaf in the hinge. There is an angle scale on the hinge for setting it. Both this and the following item were superceded by the adjustable set square in the 1920s.
A fine, Harrison's patent, mahogany clinograph by Harling.
A six inch pearwood clinograph, probably late 19th century.
Two T squares and a collection of scale rules. The large T square is a 43" one, made of mahogany with an ebony edge to rub against the board side, and a ruling edge inset with celluloid. It was made by Halden & Co. The other T square is a 28" mahogany one. Both date from the mid-twentieth century.
A Maginnis's Dead Beat Sectioner for drawing evenly spaced section lines. The distance apart could be adjusted.
A six inch "Facila" adjustable set square, and an eight inch "Verax" adjustable set square by Hall Harding. Both of these are made of celluloid and date from the 1920s or 1930s. Celluloid is the trade name for cellulose nitrate or cellulose acetate, which, when old begins to decompose and give off acid fumes Both of these are affected by this and the metal parts are becoming very corroded and fragile. It is important to keep them apart from other items in the collection.
A ten inch "New Facila Super Quality" adjustable set square from the 1930s.
The six inch size was made for inclusion in a case of instruments, the eight inch one primarily for students, and the ten inch for professionals.
A ten inch "Unique 25CB" adjustable set square dating from the 1950s or 1960s. The transparent material now used is acrylic which is much more stable than celluloid.
A French folding square in brass, a little over six inches long. The square has holes in one arm for use with a plumb bob. The folding square is divided on the plumb bob arm for 6 Pouces, which are French inches and equal 1.0659 English inches, and on the other arm for Nouvelle Mesure which is cm, subdivided to mm. The French introduced the metric system in the 1790s and it became compulsory in 1837, there being considerable resistance to its use at first. This square most likely dates to between 1810 and 1837.

A pair of mahogany framed set squares, a ten inch 30 degree and an eight inch 45 degree. Probably from the first half of the twentieth century. These are more basic, and would have been much cheaper, than the Stanley one described earlier.
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9 inch isograph by Patrick Adie, Westminster, London
Eight inch 45 degree and ten inch 60/30 degree set squares. Unlike the framed set squares previously illustrated, these are edged inside and out. The lighter wood could be from a variety of trees, possibly pear or maple, but the edging is mahogany. The figure of eight keys used to hold them together are unusual and the materials used are not those usually found on English squares so these could be continental or American There is no maker’s name but ‘165’ is stamped on both of them.
“Andy-Square” combined adjustable square and 6” Armstrong scale. Patented in 1956 no 762051 by Douglas Graham Fordyce Anderson as “Protractors for drawing and measuring angles”. This example appears to be made of celluloid.
Low’s Vector Set Square, Patent,Longman Green & Co Ltd, London, New York & Bombay. Mahogany, ebony and lacquered brass. Was the number ‘2’ the size or indicating the second side?