Raster Engraving Apparatus in French Pouces Units (0489)
Index: 0489
Year: ?
Maker: ?
Dimensions: 30 x 12 x 31 cm
Info
This apparatus was used to make engravings. The top slides over the rails on both sides while the distance between the lines is set using the handwheel where each revolution is 1 pouce. The pressure of the engraving stylus is set by adding the included lead grains into the small brass box that serves as weight on the stylus.
French Feet (Pouce du Roi) = 32,483 cm = 12 Pouces Francias
100 revolutions = 1 pouce => 1 revolution is 0.27mm
The setting wheel has 12 divisions => each division is 0.27/12 = 0.02256mm
References/Links/More Info
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