Combined Scroll- and Resaw-machines. —In shops where there is some resawing and considerable scroll-sawing, but where for want of room a large special resaw would not be advisable, a combined scroll and resaw ing band-machine may be applied, the frame being that of the ordinary band-sawing machine, to which there is a resawing attachment, consisting in one type of six rolls, of which four are geared together, the two small est next the saw and acting as guides. These rolls are driven by a fric tion-wheel and disc, which vary the feed from 5 to S feet per minute. One convenient form of band-resaw (fig. 5) has the table in two parts, divided at right angles to the saw-teeth. The front portion, which bears the feed rolls, may be thrown down and under, feed-works and all, to make out of the machine a plain band-saw. In one type of combined band-scroll and resaw (fig-. 6) the column is cored, and has in it an opening for the pas sage of the lumber. This permits the placing of the feed-works in such position that it is never necessary to disturb the rolls when the machine is changed from a resaw to scroll-work. The scroll-sawing, which takes the least thickness of cut, is done upon that side which brings the work farthest from the standard, the resawing being done in line with the stand and itself. Of course it is necessary to reverse the motion of the blade for resawing, so that each kind of work shall be done with a down-running edge. This is accomplished by placing upon the counter-shaft one tight and two loose pulleys, using a straight and a crossed belt and changing saws. In changing from one kind of work to another it is only necessary to change saws and to use the proper belt, and the machine is ready for work.
The Duplex Machine, which was suggested by the writer about 1878, has since been carried out in one in which the wheels of one band have their axes parallel with those of the other, all four wheels lying practically in the same plane, their rims being as far apart as the width desired to be left between the kerfs; the bands running in opposite directions, so as to bring both down-running sides together.
One pair of wheels has the ordinary C-shaped frame, and the other, the movable one, has a straight column, the distance being regulated by a screw and hand-wheel, which move the column-frame along the sole plate joining the two sections. This machine is especially adapted for sawing rims and felloes, the C-shaped frame having a suitable guiding arrangement for the curved cut necessary. The cored-box section of hand saw frame has driven out the I-section, being stronger and more sightly. For many kinds of fine work the band has entirely superseded both the " =flay " or free-ended and the strained jig-saw, except, of course, for inside work, for which it is unavailable. It is also largely used for resawing and for log-sawing.
driven.by machinery are also used for cut ting stone. Instead of steel, the blade, which is toothless, is of soft iron, and the cutting action is obtained by a constant current of water and hard angular sand or emery. The grains of sand, getting under the blade and being carried along for some distance, scrape off the opposed particles of stone, while the current of water constantly removes the resulting sludge. Such a stone-sawing machine is shown in Figure 3 (pl. 12). The ends of the blade are fastened in two jaws, which are connected by a belt running over two guide-pulleys and are given reciprocating motion from a revolving driving-shaft. The boxes of the guide-pulleys are on ver tical slides, which can be moved up and down by two racks and a pin ion, the block of stone being firmly held while carried toward the saw. By substituting for the toothless iron blade a steel blade with suitable teeth this arrangement can also be used for cross-sawing logs, which the draughtsman has intended to indicate in the illustration by the manner of hatching. (R. G.)