Die-frames, small and large, should be made of a soft cast steel, and cast in their respective shapes having the openings for containing the dies formed at the time of casting, so that only a proper amount of fitting shall be necessary. The bosses, which are to have inside screws, should be cast without any hole, to allow holes of proper sizes for the adjusting screws to be bored without trouble, and in their proper places. Although die-frames are of several different shapes in their intermediate parts, all sorts of frames may be cast, but the precise amount of shaping that is necessary afterwards, depends on the particular forms of the holes or slots to contain the dies. If the frame is to contain dies having vee-grooves the vee-ridges of the frame intended to fit the die-grooves, are easily shaped at the time of casting, but with sufficient metal to allow for fitting. A frame which is to have two sliding plates for holding the dies in their places, is easily slotted or planed, whether the dies to be put in are those having short stems, resembling those in Fig. 372, or whether the dies are to be taper, without any stem, similar to Fig. 379.

By casting a die-frame solid with its handles, some inconvenience may arise while planing the slots, through the handles extending across the machine; this is to be remedied by using a large planing-machine instead of a small one, if it is really needful to plane all the sides of the slot; but if properly cast, no planing is necessary except that for flattening the two broad sides of the frame, and this can be done on any small planing-machine while the lengths of the handles are parallel to the length of the planing-table.

Die-frames are frequently made of ordinary wrought iron and in three pieces for each intended instrument. One of these is the intermediate, which is forged without any hole whatever, similar to Fig. 604, the entire slotting and planing of the piece being done while cold. The two other pieces are the handles, which are of round iron and are welded to two short stems that are made to extend from the middle piece. A frame thus made is first planed on its broad sides, its curved junctions of the stems lathe-turned, next drilled, its slot shaped bosses drilled, tapped, and turned, previous to welding to the handles, and when these are attached, another turning is given to complete the cylindrical parts of the handles; consequently, the junctions that were previously turned, are made to rotate truly before commencing to turn the adjoining parts. Although this method involves a variety of processes, the turning of the junctions is greatly facilitated because it is done while the frame is short. This mode is therefore especially convenient for those makers who have not suitable stays for the lathe-turning of long slender articles.

The adjusting screws of a die-frame require to be of steel, although the frame may be of iron, and the step of the thread should be short, to prevent the screws shifting when not required, and to enable the operator to easily apply the pressure for cutting. The screw's end, which is to be in contact with the dies, is turned conical, about half an inch of the screw's length being without any thread. To prevent this tapered end spreading through being screwed tight against the hard die, the cone is also hardened and tempered to a dark blue. The frames also are hardened, if made of wrought iron, to prevent wear and burring of the edges, the hardening being done after the filing of the frame is entirely finished, by sprinkling thereon prussiate of potash and dipping into water in the usual way.