The stave is laid upon the bars of the upright swing-frame (which is pivoted at its lower end), and the latter is vibrated by hand, which may obviously be done both easily and quickly on account of the lightness of the swing-frame and its vertical position. A dimension sawing machine, by G. Richards and Company, is shown in [Fig. 3088]. This machine is designed for general fine work, such as pattern making, and its general features are as follows:

It carries two saws (a cross-cut and a rip-saw), mounted on a frame that can be quickly revolved by a worm and worm wheel to bring either saw into position as may be required.

There is a fixed table and adjustable fence on one side of the saw, and a movable table and fence on the other.

VOL II.DIMENSION SAWING MACHINE.PLATE XVIII.
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Fig. 3089.

The saws are ground thin at the centre, as shown in [Fig. 3089], so that but little or no set need be given to the saw teeth; hence the cutting edges of the teeth are more substantial and true, and as a result the work is cut very smoothly, and if the machine is kept in thoroughly good order, the sandpaper may follow the saw.

In [Fig. 3088], a is a substantial box frame, to which is bolted the fixed table t. t′ is the movable table which runs on rollers, and is guided by the ∧ slideway at e. This table the workman pushes to and fro by hand, the work being adjusted upon the table or to the fence, as the case may be. At w is the wheel for swinging the frame to bring the required saw into position.

In [Fig. 3089] the worm gear for swinging the saws into position is shown, and also a sectional view of one saw arbor and of the movable table. a is the main frame, and f the disc frame carrying the two saw arbors. The disc d is turned to fit a seating formed in the base, while the other end of the disc frame fits through a substantial bearing b; w′ is the worm wheel, and w′′ the worm for swinging the disc frame. The worm teeth fit closely to the worm wheel teeth, and backlash or play is prevented by means of the spring bearing shown at d, the spiral springs forcing the worm teeth into the worm wheel teeth. Thus a is the bearing for the worm carried in the box c, upon which is the spiral spring whose tension is regulated by the screw g.

The end of the worm is therefore held in a swivel joint that causes it to operate very easily.