Fig. 4. Turning tools for plaster.
Fig. 5. Position of tool in turning. A, correct. B and C, incorrect.
The board support and turning stick described on page 100 are used in turning plaster as well as clay. The turning stick is held in the left hand and the point is pressed into the board. All this is, of course, made ready before the plaster is poured. The turning tools are here illustrated. They are not sold in the stores but can be made by any machinist. The head or cutting blade consists of a flat piece of steel through the center of which is a shaft or pin which is driven into a handle. The head may be of any shape but the triangle and the circle will meet every need. The tool is held in right hand and braced against the turning stick, the stick and tool being moved together by raising or lowering the left hand which holds the butt of the stick.
While the plaster is still soft the round tool is used and the rough form is rapidly turned. Then as the setting of the plaster proceeds and it is found to grow harder, the triangle tool should be used and the shape gradually wrought out with the point. Finally by using the circle tool for concave lines and an edge of the triangle tool for convex lines the form is perfected. The surface is to be finished and the tool marks removed by using, free hand, a flexible scraper which is bent by the fingers and thumb to fit the lines of the form, and a final smoothing is given by fine sandpaper, the wheel being revolved all the time. At the top of the form a small cylindrical piece is left, called the "spare" which represents the thickness of the mold substance, and for the bottom a small piece is turned in the shape of a truncated cone. The small end of this should be the same diameter as the base of the vase. These are shown in the illustration (Fig. 6).
Fig. 6. Vase with foot piece and template. A, vase. B, spare. C, foot piece. D D, templates. N N N N, natches.
It will be obvious that in the directions given above the base of the vase is not finished off and therefore the form must be cut off from the bat, either by a knife or saw, and the base is then finished by hand, or by setting the form upside down in a clay cradle—called a "chum"—and turning the base true. The form is now ready for molding.
