Fig. 1204.
In [Fig. 1204] the straightening device is shown. A frame consisting of two parts, f, f′, is gibbed to the edge of the shears at g and h. The upper part of this frame carries a square-threaded screw i, and is capable of sliding across the shears upon the part f′. It rests upon the shears through the medium of four small rollers (which are encased), two of which are at j, k, and two are similarly situated at the back of the frame f′. The motion of f across the machine is provided so that the upper part f may be pushed back out of the way, to permit the shaft being easily put on and taken off the friction rollers r r′. The motion along the shears is provided to enable the straightening device to be moved to the required spot along the shaft s′. The shaft s is laid on two pieces n, p, and a similar piece r is placed above to receive the pressure of the screw i, which is operated by a hand lever to perform the straightening. The pieces n, p rest upon two square taper blocks v, which are provided with circular knobs at their outer ends to enable them to be held and pushed in or pulled out so as to cause n, p to meet the shaft before i is operated. This is necessary to accommodate the different diameters of shaft s. The operator simply marks the rotating shaft with chalk in the usual manner to show where it is out of true, and then straightens wherever it is found necessary.
Fig. 1205.
[Fig. 1205] represents a similar device for straightening rods or shafts while they are in the lathe. a is a frame or box which is fitted to rest on the Vs of the lathe shears, the straightening frame resting on the box. Instead, however, of simply adjusting the height of the pieces p to suit different diameters of the shaft, the whole frame is adjusted by means of the wedge w, which is inserted between the frame f and the upper surface of the box a. At h is a hole to admit the operator’s hand to move a along the lathe shears.
Fig. 1206.
A method of straightening wire or small rods that are too rigid to be straightened by hand, and on which it is inadvisable to use hammer blows, is shown in [Fig. 1206]. It consists of a head revolved in a suitable machine, and having a hole passing endways through it. In the middle is a slot and through the body pass the pins a, being so located that their perimeters just press the rod or wire when it is straight, and in line with the axis of the bore through the head, each successive pin a touching an opposite side of the wire or rod. It is obvious that these pins in revolving force out any crooks or bent places in the wire or rod, and that as the work may be pulled somewhat rapidly through the head or frame, the operation is a rapid one.