The Practical mechanic's journal . ton ? . ? . THE PRACTICAL MECHANICS JOURNAL. 85 REGISTERED DESIGNS. DUPLEX STRAIGHT-EDGE PROTRACTOR. Registered for Geoege Simpson, Esq., Mining Engineer, 3 West KileStreet, Glasgow. Illustrated by Plate 9. Fig. 1 of the drawings ou this plate represents a quarter size plan viewof the Protractor; fig. 2 is a longitudinal section. The graduated quad-rant, forming the index for the angles, is in one piece with a parallelhar, a, which is connected at each extremity by means of transverse bars,o b, with a similar bar, a, the space between the two being of such aw
The Practical mechanic's journal . ton ? . ? . THE PRACTICAL MECHANICS JOURNAL. 85 REGISTERED DESIGNS. DUPLEX STRAIGHT-EDGE PROTRACTOR. Registered for Geoege Simpson, Esq., Mining Engineer, 3 West KileStreet, Glasgow. Illustrated by Plate 9. Fig. 1 of the drawings ou this plate represents a quarter size plan viewof the Protractor; fig. 2 is a longitudinal section. The graduated quad-rant, forming the index for the angles, is in one piece with a parallelhar, a, which is connected at each extremity by means of transverse bars,o b, with a similar bar, a, the space between the two being of such awidth as to admit the straight-edge, e. A central transverse piece, d,which is screwed to the two bars, a a, carries a pivot or joint-stud for theeye of a radial straight-edge, ef, having its edges bevelled off for rulingclose to the paper. On this radius bar are fitted two parallel bars, g g, each in one piecewith the straight-edges, /* h, being braced together by cross pieces, sothat the whole may slide loosely upon the radiu
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Keywords: ., bookcentury1800, bookdecade1840, bookidpra, booksubjecttechnology
