PATTERN 7.
Set the cutter to the middle of the circle, enlarge it two turns and a half, cut a circle in the middle, turn the chuck down two turns, so as to cut another a little into the former ones; continue the same till the seven are done; return to the middle circle, and cut the other six in the same line, by screwing the eccentric chuck upwards instead of downwards. When the thirteen are completed, lower the chuck one turn, and screw the slide rest outwards (if doing the lines to the right) two turns, cut a circle, then move the eccentric chuck downwards as before, till the second line of circles is cut, each line diminishing one turn of the eccentric chuck at the top and bottom.