Pedal Powered Tools

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 up–in a vise, and hacksaw a vertical
split down the center of the just-formed, cone-shaped
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″ hole saw, 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
just drawn 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 … but only after countersinking the holes in the plate to keep the screw
heads flush with the upper surface.

It’s a Sander, Too!

The other half of our tool is a disk sander, and you can
easily attach this implement on the flywheel of your
recycled “one lunger.” To do so, lay the rotating
counterweight flat on your work surface, then take the 3/4″
X 8″ circular plywood blank, center it over the flywheel,
and drill three evenly spaced 1/4″ holes through both
components. Now countersink the bores slightly with a 1/2″
bit, and cut a 1 “-diameter hole through the center of the
wooden circle.

Next, secure the disk to the flywheel with three 1/4″ X
1 1/2″ bolts, and reinstall the counterweight on the
crankshaft. The sandpaper can then be glued to a metal
plate, which is in turn fastened to the plywood by means of
three countersunk No. 6 X 1/2″ flathead wood screws placed
near the outer border of the metal circle. (You might also
take this opportunity to wrap some duct tape around the
flywheel to cover any sharp edges.)

At this point, mount the engine block on its 3/4″ X 10″ X
20″ wooden base. Of course, since it’s best if both the
drive pulley and the sander extend beyond the platform
slightly so the stand won’t interfere with the belt or with
your ability to smooth an oddly shaped piece of work, you
might want to trim down the foundation’s width accordingly.
In any case, position the mechanism on the board, drill
four 5/16″ mounting holes in line with those already in the
block’s base, and install four 5/16″ X 2″ bolts to hold the
engine in place.

With this accomplished, you can knock together a little
sanding platform. Take your 3/4″ X 3 1/4″ X 13″ board and
remove a 1″ X 8 1/2″ notch from the center of one of its
sides. Then cut out a 3/16″ X 3/4″ X 3 1/4″ groove–centered
2 inches from each end–from one “face” of the board;
place one of your 3/4″ X 3 1/4″ X 5 3/4″ support pieces
against one end of the sanding platform; and, with the
miniature table held perpendicularly against the sanding
wheel, scribe a line to indicate the angle to which you’ll
need to cut the support. Duplicate this angle at a spot
4 1/2 inches below the initial line, then mark a
perpendicular from a point 1 1/4″ behind the leading edge
of the support to its base. Make your cuts on these lines,
then trace the pattern on the second piece of wood and make
similar cuts.

To secure the assembly to the mounting platform, simply
fasten the sanding ledge to the supports with four No. 6 X
1 ” flathead wood screws (countersunk to insure a smooth
surface ) … then lock the legs to the base, using four
No. 6 X 1 1/2″ wood screws placed so that one enters each
support from the front and one passes into each from the
base.

You can then complete the combination sander/cutter by
tacking a couple of 3/4″ X 1 1/2″ X 20″ wooden feet below
each flank of the mounting platform. Once that’s done,
you’ll be ready to bolt or clamp the tool to a convenient
work surface, loop a belt between it and the cycle power
chassis, and have at an appropriate piece of wood (with the
help of a willing–and physically fit-friend, of
course). And, if the idea of pedaling up your power doesn’t
strike your fancy, you can still use this two-in-one device
by simply attaching an electric motor to the platform and letting the power company do the work.