CYCLE POWER, PART III

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With a little ingenuity, you can put pedals to work in your wood shop:

In our last issue (see No. 68, page 134), we described how to generate DC electricity by connecting the basic cycle power chassis, as featured in MOTHER NO. 67, to an automobile alternator. (See page 116 to order back issues.) This time around, we're going to show you how to build a jim-dandy combination disk-sander/reciprocating-saw that fits the pedaled powerplant like a glove.

SCROUNGED FROM SCRAP

The backbone of our "treadle" tool is a worn-out upright lawnmower engine, the likes of which are available in just about any junkyard. If the unit you locate has belt drive, fine ... if not, you'll have to remove the chain sprocket and simply install a pulley that's compatible with the motor shaft.

Then take off your engine's cylinder head, carburetor, muffler, flywheel housing, and any other components that aren't part of the "working" block. Next, drill a 1/2" centered hole in the top of the piston and tap it to accept 1/4" pipe .. . before threading a 1/4" to 5/16" ball compression fitting into the tapped hole and snugging it down firmly.

Once that's done, take a 3/8" bolt and grind the threads from the last 3/8" of it to form a taper, then grip the fastener—end upin a vise, and hacksaw a vertical split down the center of the just—formed, coneshaped nub. Finally, cut the two "half rounds" from the rest of the bolt . . . these will function as the tapered split pins that will hold your saber saw blade in place.

Secure the reciprocating cutter by setting its mounting bayonet into the socket of the compression fitting and slipping the split cones-tapers down-into the semicircular openings on either side of the metal "tongue". You can then slide the nut over the blade and lock it tightly onto the fitting.

To make a flush cutting table, take a piece of 3/4" X 12" X 15" plywood and, with a 2-1/2" We raw, drill a centered opening 5 inches from one long edge. of the board. Now, using the discarded cylinder head—and its mounting bores—as a template, mark and drill four 5/16" holes into the platform, at points evenly surrounding the aperture, and countersink them 5/16 inch with a 5/8" bit. Next, take the 1/8" X 6" metal disk and drill a 1/2" opening at its central point . . . then align this hole over the 2-1/2" port in the wooden table, and trace the plate's circumference with a pencil. Finally, using the justdrawn line as a border, rout out all the wood within the circle to a depth of 1/8 inch, and use the original head bolts to fasten the plank to the top of the engine block. (To assure that the compression fitting won't strike the metal plate at the top of its upward stroke, place the piston in exactly that position, and then slip washers or nuts under the plywood platform to raise it slightly.) Now fasten the cover disk into its recess in the table with a pair of No. 6 X 1/2" flathead wood screws . . . after first countersinking the holes in the plate to keep the screw heads flush with the upper surface.