PATTERN 3.
Count 40 on the eccentric chuck wheel for each of the three large circles, diminish one turn of the eccentric chuck. Then diminish the circle two turns of the rest screw, and lower the eccentric chuck two turns, and cut a circle every 20 numbers; the others are done the same. For the second pattern of circles, cut one for every number on the eccentric chuck wheel; then move one number on the eccentric chuck wheel, and move the eccentric chuck downwards one turn, and cut a circle every 15; by moving the chuck down, and advancing one number every time, the circles are made to incline sideways. The outer pattern is much the same as in the two former ones.
PATTERN 4.
This is a double shell in the centre. Begin with the large circle, having fixed the eccentric chuck wheel at No. 120. Having cut one whole shell, move the wheel to No. 60, and work the other in the same way. For the circles, keep the tool in the same place on the slide rest, and screw the eccentric chuck down two turns to clear the edge of the shell; cut one circle every 12 numbers on the eccentric chuck wheel, enlarge the circle by moving the slide rest one turn forwards; cut the second row, and so on till the fourth or largest one is done, then diminish the size for the other two WITHOUT altering the chuck, but counting the same. The white dots are worked out with a flat-ended tool, cutting one every six numbers on the eccentric wheel; then move your chuck downwards three turns, and cut one every 12; this done, move back to the former row to the dot that comes between the circles, replace the double angular tool, enlarge your circle, and cut one every 12; screw the chuck downwards three turns, and proceed the same; then screw the chuck upwards one turn and a half, which will bring your tool to a level with the middle of the two former circles; move the eccentric chuck wheel one number on each side of the former ones, and the rosette will be finished. The border is formed of plain circles, omitting 3 numbers every ninth cut.
PATTERN 5.
The middle and second row of circles are too simple to require explanation. For the clusters of rings, begin with the middle row; cut two a little apart from each other, then one through the middle of them, and so on to the end; set the eccentric chuck wheel to the middle circle of one of the clusters, and move the eccentric chuck downwards, till the tool can cut through the middle of the others, then upwards the same number of turns. The extra half circle is made by moving the wheel of the lathe with the hand, as for the arc patterns, and counting the numbers on the eccentric chuck wheel, between those already formed.
PATTERN 6.
This is merely a circle of shells, worked the same as in pattern 1; only with this difference, that each circle is done to correspond in each shell, instead of working every one separately, which would be more tedious; 15 is counted on the eccentric chuck wheel for each row of circles. The rays in the middle are done with the drill; these can also be done without an eccentric chuck; the numbers must then be counted on the fly-wheel, which, for this kind of line work, is kept steady with the stop.
PATTERN 1, [PLATE 12.]
Cut a small circle, then one every 12 numbers on the eccentric chuck wheel. Move the chuck downwards two turns, and the eccentric chuck wheel 1 number, either backwards or forwards; if the former, the rows of circles will incline to the right; if the latter, to the left. Proceed the same for every row of circles, always counting twelve between each, and advancing the chuck 1 number at the beginning of every new row.