to the required size-1 inch. With the point hook-tool or a side tool, turn off the end of the iron, either quite flat, or slightly convex, as required. Reverse the work in the lathe, and turn off the other end to shape, and so as to make the work the proper length. Then commence anywhere in the length of the work, and with the round hook-tool held as directed, rough down the metal nearly to its proper diameter. It is best to do this first in several narrow bands at intervals of an inch or so along the rod; as these turned portions then act as a guide in roughing down the other parts without having to use the callipers. When all that portion is roughed down, again reverse the work in the lathe, and rough down that portion of the work previously covered by the carrier. Now take the flat chisel, Fig. 88, and turn down several bands to the finished size, or very nearly so; and finish turning the whole length in the same manner as before, carefully using the callipers at short intervals to see when the right size is attained. In putting a carrier on to work which has been smooth-turned, in order to prevent the point of the tightening screw jamming against the bright work and disfiguring it, a piece of sheet brass or copper should be bent to a ring to encircle the work and come between it and the carrier. The work being turned to size can now be polished by any of the methods previously explained-the relative positions of the tools and work of various materials are shown at Figs. 92, 94, 105, 108. The figures explain themselves to a great extent.

For a second example, take a brass ring, say of 1-inch diameter, 1 inch wide, and having a hole

through it of an inch diameter. Such a piece of brass would be obtained by casting it from a wooden pattern slightly larger than the finished size. The hole having been made the method of doing this will be explained hereafter-take a 3-inch standard mandril, Fig. 78; put the ring on this, and hammer it well on.

To knock work on or off mandrils, a mandril-block should be used, the work placed with its hole just over the hole in the die of the block, and the mandril put through both holes, and, if a small mandril, it should be knocked in with a mallet or soft iron hammer. If an ordinary steel hammer be used, it must on no account be struck direct on the end of the mandril, as that would probably cause a piece of the hammer or the mandril end to fly off, and so injure the mandril, or if the mandril end be rather soft it would be hammered out of shape, so that when placed between the centres it would not run true. A piece of lead or copper should therefore be placed upon the mandril end, and the hammer struck upon that.

If the work be very heavy, it may be driven on or off without any hammer, by lifting the mandril with the work off the ground, and allowing it to fall with its end on to a block of wood or lead; the motion of the mandril being thus suddenly destroyed, the momentum of the collar will generally suffice to drive it either on or off the mandril as the case may be. In driving a collar on in this manner, the small end of the mandril must be held uppermost, and the large end be brought down against the wooden block; in driving the work off, the ends must be reversed.

The practice of striking out mandrils with a centre

punch is to be strongly condemned, so also is that of using the ordinary steel-faced hammer direct upon the mandril end.

In hammering such articles as wheels or pulleys with arms, on and off mandrils, they should not be rested upon the rim, but upon the boss or the metal nearest the hole; and if the rim project in the way, a collar should be put on the mandril between the boss and mandril block, to transfer the force of the blow to the boss of the pulley.

To return to the example which is now on the mandril, put a carrier on the end of the mandril, and let the point of the tightening screw jam against the flat, cut on the mandril end. Place the mandril between the centres, and put a drop of oil about the centre previous to screwing the spindle tight up. The centres should be screwed up only just tight enough to hold the work between them without looseness; so tight that when the end of the carrier is taken in the fingers, and the work pulled round, the workman can just feel the resistance.

Now adjust the rest for using the round-nose chisel, Fig. 90, and with this tool rough the work all over, and reduce it nearly to its right size. Remove the rest, and put in that one shown at Fig. 54; adjust this for using the scraping tools. With Fig. 95 finish the edge of the collar, and, with Fig. 96, finish the sides-polish the whole, if required, by any of the methods described. These scrapers should be kept very keen and smooth; after grinding they should be rubbed on a good oilstone until the stone marks are removed, and the cutting edges are smooth and bright. They

should not be allowed to get very dull; but whenever they become slightly so, a few rubs on the oilstone will restore the edges. A good keen scraper, properly used on brass, will produce a surface beautifully bright and smooth.

Surfaces are turned in the same manner, but with the rests facing the work, the truth or flatness of the surface being judged by a straight edge, which is merely a piece of thin steel with its edge brought to a perfectly straight line.

SCREW-CHASING.

Besides the work already described, screws can be cut in the hand-lathe by means of suitable tools; and this method can frequently be conveniently followed in other lathes, even those especially constructed for screwcutting, owing to the mechanism being required for purposes which renders it inconvenient to alter its arrangement.

The hand operation of cutting screws

is termed chasing, and the tools used FIG. 109. FIG. 110. are called chasers or combs. The tool shown at Fig. 109 is the outside chaser, and Fig. 110 is the inside chaser. These tools are the exact shape of the grooves of the screw, and are also inclined to the same extent; they are to be procured of standard threads of all tool makers, and the method of making them will be hereafter explained.

One of these tools will answer for cutting a screw upon any diameter of work, and a skilful workman can cut a thread of double or quadruple the pitch; but

this is an operation that not many can manage satisfactorily.

For cutting left-hand threads, the chasing tool must be inclined in the other direction, although for a makeshift the right-hand tool is occasionally used to cut threads of reverse inclination. This is not difficult to do, but there is not the same certainty of producing a true thread. With the proper tools it is equally easy to cut right or left-hand threads.

The method of using these chasing tools is extremely simple, but is not easily acquired. A short explanation will give the reader a good idea how to proceed, but practice alone will enable him to cut a screw with truth and certainty.

The work upon which the outside screw is to be cut having been turned somewhat larger than the diameter of the outside of the required thread, it is held in the lathe precisely as for turning, but if driven by a carrier, the tail of the carrier should be tied to the driving arm of the lathe, to prevent any stopping about.' The ordinary hand-tool rest for iron can be used, but the rest used for wood-turning is the best for the purpose. Whichever is used, the top edge must be quite smooth and free from ruts or grooves, and its edge should also be parallel with the line of centres; it should be fastened at such a height as will bring the edge of the chasing tool just level with the centres ; also it must be close to the work.

The chasing tool is held in one of the ordinary handles, and applied in a very similar manner to the metal-turning chisels, being for heavy screws pressed against the work by the workman's shoulder. The tool