Chipping of the flanges belonging to steam-cylinders and similar objects, is necessary only when a planing-machine cannot be employed, or when it happens that only a very small portion of a large cylinder or other object is to be surfaced. In such cases the surfacing can be done with chiselling, in about the same time, or less, that would be occupied in moving the object and fixing it to a planing-machine.

A small cylinder which is to be chipped, instead of machined, is denoted in Fig. 819. After the cylinder is bored it is placed upon a table and enders fitted to the ends, in order to find the centres, and thus indicate the major axis. It is next packed up or wedged up with packing-pieces of suitable thickness, as seen in the Figure, to place the axis parallel to the table's surface, a scriber-block being repeatedly applied to both enders until adjustment is effected. During this adjustment the scriber-point must also be placed to two opposite sides of the steam-port flange, that the bottom edges of this portion may be also placed parallel with the face. This adjustment being completed, the cylinder is ready for being scribed upon the four narrow sides or edges of its flange. In order to properly place these lines, the desired thickness of the flange is ascertained and marked by a dot or a short mark on the edge, or, properly speaking, on the narrow side, the distance being measured from the bottom edges, which are those situated nearest to the table. Supposing the flange, now in its rough state, to be an inch and a sixteenth thick, and that it is to be finished to seven-eighths thick, a mark or dot is made upon the narrow side at seven-eighths from the lower edge, and such a mark will show, by inspection, that three-sixteenths of an inch of metal is to be cut off. The final scribing of the flange is now effected by adjusting the scriber-block point to the dot or mark on the flange while the block rests on the table, and scribing a periphery entirely around the flange upon all its four narrow sides. In the Fig. (819) a scriber-block is shown in position for marking this periphery, which is afterwards used as gauge-lines to which the rugged superfluous metal is chipped.