Jig-saw.
A vertically reciprocating saw, moved by vibrating lever or crank-rod, as in Fig. 2722, in which the saw is arranged between two sliding headblocks, to the upper one of which is attached an index to mark the bevel, a vernier plate being fixed to the circular iron-banded timber to which the blocks are secured by braces. It is moved by a segment of a cog-wheel under the carriage, gearing and working into pinions, and by a pulley-band over a drum. Fig. 2723 is a form of portable jig-saw, which is readily attached to a carpenter's bench or an ordinary table by means of a screw-clamp. The iron arm terminates in the guide d, in which works the spindle to which the upper end of the saw is attached, its lower extremity being similarly held in the guide underneath the table. A constant tension of the blade is maintained by the bent springs e and f. Motive — power is communicated from the treadle, which may be attached, at any convenient point on the floor, to a rod which forms a sleave for a smaller rod, which is connected with the crank of the large wheel a. The object of making the rod in two portions is that it may be adjusted to suit any hight of table, and afterward held in position by the set screw. Around the circumference of the wheel a is placed a covering of leather, by the friction of which the pulley b and the fly-wheel connected therewith are actuated. By means of the pitman, as shown, motion is transmitted to the saw. g is an adjustable metallic foot, designed for holding the work in place while being operated upon. |
| Jig-saw. |
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| Portable jig-saw. |
