PATTERN 2.
Begin with a small circle in the middle, then turn the eccentric chuck down two turns, and cut one every 15. For the other two rows proceed the same, lowering the chuck two turns, and counting 15 for each on the eccentric chuck wheel. For the chain work, cut a circle every 15 near the edge; then screw the eccentric chuck one turn upwards, move 1 on the eccentric chuck wheel on each side of the others; thus, if the upper row of circles begin at 120, the second row will begin at Nos. 1 and 119, then at Nos. 14 and 16, and so on: the third and fourth rows are the same as the two first; and the last is cut between the others.
Plate 12.
Patterns 3 and 4 are called arc patterns, and are worked in a different manner. In [plate 4], fig. A is a drawing of the brass fly-wheel of the lathe, with the numbers marked upon it. D is a brass circle half an inch wide, which is attached to it: and upon which are marked 144 lines, every 18 of which is described by a number. B B are pieces of brass which, by means of a groove in the edge of the circle, fit upon two steel slides that fit into the groove, and are kept firm by two nuts, which fix them opposite any number you wish. P is a long thin piece of steel, which enters by one end the bed of the lathe, so as always to stand quite upright, by which means, when the brass fly-wheel is gently turned with the hand, the flat end of the stop, P, catches upon the lower piece of brass, B, and if you reverse the motion of the fly-wheel, the other piece, B, will rest upon the stop, so that you will find the wheel can only turn half or three parts round, just as you choose to set the stops. These patterns, it will immediately be seen, are worked with the hand, which must guide the wheel slowly up and down; therefore slip off the cord, and having arranged a double angular tool in the slide rest, hold it up to the centre of the work, put the stop, P, into the hole, n, of the bed of the lathe, and gently move the wheel till you find the extent of circle you wish to cut; fasten on one slide firmly, then fix the other end of the arc, and fasten the other slide. This done, approach the tool carefully to the wood, and cut the first long arc by moving the fly-wheel with your left hand as far up and down as the stop will allow; then move 20 numbers on the eccentric chuck wheel for every one of the other five arcs, and cut them in the same way. After these are completed, move one number on the eccentric chuck wheel and unscrew the UPPER slide, and move it down as many lines as you think fit, in order to shorten the next arc; count 20, as before, for every other of the 5. Each row is worked the same, shortening the arcs and advancing one number on the eccentric chuck wheel for each row. Pattern 4, and the border in pattern 1, [plate 11]., all are done in the same manner, only counting differently. A great variety of arcs can be worked, and have a very curious effect, but you must be careful in cutting them not to let the tool go too deeply into the wood or ivory, or it will either stick fast, or else cut jagged, uneven arcs; rather prefer to spend more time over the work, by working the arcs over and over again till the proper depth is obtained.
These patterns will enable the learner easily to discover and invent many others, all beautiful when properly and neatly worked.
PATTERN 5.
Cut a circle every 24 numbers of the eccentric chuck wheel. Lower the chuck one turn, and cut a circle on each side of the former ones, so as to form the five knots of threes. The edge is worked like the arc patterns, making each half circle meet and join with a dot, cut with a small flat-ended tool.
PATTERN 6.
For the border cut three circles, one for each number on the eccentric chuck wheel, then cut another at 6, 7, and 8, and so on till all are done. The pattern in the middle needs no explanation.