Cast-iron columns are often ornamented or fluted as shown in the half section of a fluted column in Fig. 251. In all such cases the body of the pattern is made octagonal as shown by the line A B CD E. The loose pieces forming the flutes are held to the main body by pins that stand at right angles to the line A E. After the sand has been rammed, the body included in the lines A B C D E is lifted out leaving the parts A a b B, B b c C, etc., imbedded in the sand. Then one after another these are lifted out.
These fluted sections should never be so few in number that they cannot be lifted out without tearing the sand. Eight or twelve sections will be needed.
Other forms of ornamentation are put upon columns in a similar manner. Leaves or flowers are held by pins or in grooves in such a way that the main body of the pattern can be lifted out without disturbing them, and they are then withdrawn from the sand through the cavity left by the main pattern.
Cores for columns may be made in core boxes as in the case of those for pipe, but where the core is long and straight no core box is needed. The core is usually built of loam about an iron pipe as explained in Foundry Work. Where the core is to follow the lines of the ornamental mouldings on the outside of the column, it may be provided with a special core box or better with a sweep as shown in Fig. 252. This sweep is used to shape the loam core that is to be built up on an iron pipe. Fig. 252 is the outline of the template that is to be used in sweeping the core for the interior of the columns shown in Fig. 253.
All thin patterns that are likely to suffer distortion from the pressure of the sand while being rammed up, must be provided with accurately fitting follow boards. These follow boards may be made to fit on either one or other of the. sides of the pattern.
When the outlines of the pattern are very irregular, the follow boards are often made of plaster or other composition, which, when dry, is used to support the pattern while the drag is being rammed.
Fig. 254 represents a section of a railing cap. If the pattern 13 were to be set with the edges a a resting upon the moulding board and the sand of the drag rammed down upon its upper face, it would be sprung out of shape. To avoid this the follow board A is made to exactly fit the under side of the pattern. Then when the sand is rammed, the whole pattern is supported and there will be no distortion. When the cope is rammed the follow board is removed and the sand of the drag supports the pattern while the cope is being rammed.
THE WHITING CUPOLA.