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.