In order to get the most out of the stock given, and also to lessen vibration at the lathe, it is essential that one learn how to locate the center of the wood to be turned.

Fig. 9,1 illustrates a very simple and most commonly used method for locating the center. If the ends of the stock are square or nearly so, we know from geometry that the diagonals of the square bisect each other at the center.

Fig. 9.

Any straight edge will do for drawing the diagonals. Stand the wood on one of its ends and with the aid of a rule and pencil draw the required lines. The bed of the lathe or top of the tee-rest can be used to butt the wood against, to save looking for and handling a straight-edge.

Fig. 9,2 illustrates a method used on wood that is much out of square. Set a pair of dividers either a little greater or a little less than half the thickness of the wood, and, holding the block on something flat, scribe the four lines from the different sides. The center can thus be readily located. Instead of the dividers a parallel block or marking gauge can be used to obtain the same result.

Fig. 9,3 illustrates a rough piece of wood with no true shape. In order to get the desired diameter out of this stock it is necessary to draw the largest possible circle at each end.

In commercial turning, these methods are not generally used. The turner makes a guess at the center, starts the wood in motion (by hand) and gently puts his gouge in contact with the wood, whereupon only the high corners will be hit. By lowering the wood with a tap or two of his mallet, hit on the high side, the wood is accurately centered. It must be understood, however, that the guess must be a good one, and this only comes with practice.

Fig. 10.

Fig. 11.

When a large number of pieces are to be turned, especially those of large dimensions, the turner often cuts a block as illustrated in Fig. 9,4, the distance AB being equal to exactly one-half the thickness of the stock. By using this as a gage and drawing two lines from adjacent sides, the center is accurately and quickly located.

The center having been found, the next step is to place the wood in the lathe. With the aid of the ramrod, drive out the live center of the lathe, then drive this center into one end of the wood (the end upon which the largest amount of turning is to be done). A mark, x, should be filed on one of the blades of the live center, and a corresponding mark put on the part of the wood this blade is to enter in order to indicate which blade was at that place. This is done so that the work may be removed and put back without shifting the center.

Place the live center and wood in the lathe, holding the latter with the left hand. With the right hand, turn the spindle of the tailstock out about 1", and then move the tailstock up to the work so that the dead center just comes in contact with the wood; then clamp the tailstock in place. Next, the dead center is forced into the wood by turning the spindle screw. At this point a drop or two of oil placed on the dead center where it comes in contact with the wood will ease the friction caused by the revolutions of the wood against the dead center. Now clamp the spindle securely to prevent it from working back while the piece of wood revolves.

Turn the wood so that one of the end diagonals will be horizontal, then move the tee-rest as close as possible to the work, having the top on a line with the edge of the wood, Fig. 11. Clamp the tee-rest in place. The height at which the tee-rest should be placed should be determined solely for the comfort of the student or worker.

Before starting to turn, try the various adjustments to make certain that all are secure, and revolve the wood by hand to make sure that it clears the tee-rest.