The tools for turning iron and steel, whether in long or short handles, are nearly always held underhand, at about the vertical angle of the graver fig. 461. The right hand is grasped around the short handle, knuckles uppermost, the wrist and thumb generally in contact with the right chest; the left hand is placed around the shaft of the tool, the knuckles also uppermost, in contact with the right hand, or sometimes partially around the latter and the stem of the tool also.
The weight of the body is always brought to bear, more or less, upon the tool, by leaning the chest upon the clenched right hand around the end of the tool handle; but with greater necessity and therefore more decidedly during the first roughing cuts, that it may then assist in holding the tool with the greatest possible firmness to prevent any endlong motion, to which it is always liable until the work has been reduced to the true circular section. The manner in which the long handled tool is held underhand for turning iron, has already been described in the chapter on softwood turning; and occasional variations in the position of both hands and tools in metal turning, will be referred to.
One corner, the angle formed by the side of the shaft and the bevil to which the graver and other tools are ground for turning iron and steel, is placed on the surface of the tee, into which it slightly penetrates by the resistance in cutting; the thrust of the cut is thus sustained by the rest instead of the hands, which only direct and retain the tool in position. The tee of the rest is placed close to the work, and is much shorter than those used for wood turning, and so far as possible, the tool is placed near to its center or over the stem of the tee, in which position it is most solidly supported and acquires the least vibration; the short tee being shifted along the work from time to time, that the tool may be always retained upon it at about the same position.
The brass tools are held in several different positions; the routers figs. 450. 451, and sometimes the square tool, fig. 458, in either long or short handles, when used for strong vigorous cuts, are held after the same manner as the graver in turning iron. For less forcible use, the right hand is placed around the handle of the brass turning tool with the thumb, instead of the knuckles uppermost, the left hand remaining as before; but the shaft of the tool is then much less underhand. The latter of the two positions is the more general with the finishing tools, figs. 452. 454. and 456; while for very light cutting, these tools are held in the horizontal manner, slightly more sloped but otherwise precisely the same as the hardwood tools.