PATTERN 3.
This pattern requires great attention and care to work it properly. Having arranged the cutter tool, screw it out four turns to make the circle the proper size, then move the cutter to the edge of the work, cut a circle at Nos. 120, 40, and 80, on the eccentric chuck wheel, then set the wheel at 20, and leave it fixed. Your next operation must be to screw down the eccentric chuck, and alter the position of the tool on the slide-rest, till, by laying your hand on the fly-wheel and moving it gently, the tool of the cutter appears to describe a half circle across the wood, in the same way as for the arc patterns. Having arranged the first arc, move 40, as before, and see whether the second will exactly meet it, then the third; they should each diverge from the centre of the first circles which were cut round the edge; if they do not exactly fit, move the chuck up and down, and the slide-rest screw backwards or forwards, till you find the exact position; as, however, the arc is difficult to settle, the line being of course an imaginary one, as the tool must not touch the wood, it is a good way to cut a piece of pencil to fit like the tool into a box, and with it mark the arcs; they will easily rub out, and thus you will be able to be more certain of your proper distance and position. The next thing is, to see on the fly-wheel of the lathe how many numbers are required to form the arc; thus, if it begins, as the one I have worked did, at 360 of the brass wheel, and ended at 85, stop the wheel at the former number, cut a circle, then one at every fifth number on the same wheel, till you arrive at 85; then move forty numbers on the eccentric chuck wheel, and do the other arc the same; then the third one.