PATTERN 4.
The arc pattern is first worked: arrange it as directed for pattern 3, and mark the outline with a pencil: in this, the arc began at 280 of the fly-wheel, and ended at 168, making in all 116 numbers; to divide 58 for each half of the arc, divide them thus—4, 5, 6, 7, 8, 9, 10, 3, 4; then count back 4, 3, 10, 9, 8, 7, 6, 5, 4. You will see that the numbers increase one every time or for every circle, which also is enlarged one notch for each. Having made the three arcs fit by marking their position with the pencil in the cutter box, cut a very small circle at 280, enlarge one notch, count 5, cut another, enlarge a notch, count 6, and so on till you have counted, in all, 49 numbers; do not enlarge the circle, but cut one, counting three numbers, then 4, which will be the middle, then 4 again, then 3, then 10; after 10, decrease the circle one notch for every cut, and count backwards, 9, 8, 7, 6, 5, 4. The other three arcs are done the same, by counting 40 for each on the eccentric chuck wheel; for each of the crowns cut five circles just above the arc, by counting one number for each circle on the eccentric chuck wheel, then lower the chuck one number, and cut the same circles again through the others; lower it half a turn more, and cut two circles; then half a turn again, and cut one circle above and between the last two.