The simplest class of columns are made cylindrical, and of three pieces. Of these, one is the column itself, and the two other pieces are the collars or bearings. Each of these two is separately forged, and afterwards fixed to the straight piece which may be called the column proper. Such a method obviates the necessity for the drawing down of a thick piece which is the diameter of the required collars.

Cylindrical columns of this simple form are much used for oscillating engines and some classes of land engines; and when short columns are required, they may be forged also by making the collars solid with the remainder of the work. With this object, two pieces, whose diameters are equal to those of the collars, are drawn down to the desired diameter and length, and so welded together that the joint may be about the middle of the column when finished.

The class of columns represented by Fig. 130 are used also as stays, and in the horizontal position ; they are in such cases named stretchers, and should be forged as nearly as possible to the intended form, by which a large amount of reducing during the lathe process will be avoided. Small stays of this shape are easily forged to the required form, and the two collars welded to the work at the conclusion. Large ones, also, are made of three pieces ; the screw end and the adjoining collar are one piece, and the opposite end and collar constitute another piece. These two are the pieces first made, when a large column is required, and are produced by drawing down the ends of thick pieces whose diameters are about equal to those of the collars required. After the proper length and shape of these two portions are attained, the third component piece is forged to its shape and dimensions, and welded between the other two, to become the middle or intermediate part of the stay or column.

Large columns may be made also by forging the collars separately, and afterwards fixing them to the column by either welding, or shrinking the collars to the column during the lathe process.