—Zulu proverb.
The turning or shaving operation takes place when the green shape has dried to a leathery condition. It consists in shaving the sides and hollowing the base until the thickness is uniform. The shape is thus made much lighter and rendered less liable to crack from unequal contraction. At the same time a fine finish is imparted to the surface.
One of the handiest tools for shaving is shown in Fig. 27, no. 6, but a piece of hoop iron bent at right angles and shaped with a file will serve. Small hollows can be finished with a modelling tool. An old piece of leather will close up and finish the surface. In factories a horizontal lathe is usually employed, the shape being fitted over a chum or chuck. Skilled men can turn shapes down until they are scarcely thicker than tin, but this, it is needless to add, is an abuse of method even with porcelain, and quite out of place with stoneware or earthenware. All that is necessary is to trim the thick sides, hollow the base, and smooth the surface. (Fig. 35.)
Fig. 35
A simple way to arrive at this is to throw on the wheel a chuck of stiff clay to fit the shape, wide-mouthed ones being fitted over and ordinary shapes within the chuck. (Figs. 36 and 37.) A piece of soft linen is placed over this chuck to prevent sticking and the shape fitted and centred. When spinning quite truly from right to left and steadied with the left hand, the tool should be gently applied as shown in the illustration. Hollow the base and then shave the sides, turning all down very gradually and improve the outline as much as possible in the process.
Fig. 36
Fig. 37