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456MAKE THE
CATAPULT FRAME
Drill four 1⁄16-inch pilot holes through
the 10-inch frame pieces, with the holes
1¾ inches from each of the four ends
and centered vertically. Drill a pilot hole
into the center of each end of the cross-
members [1].
Apply glue to the ends of one cross-
member and near the pilot holes on
the inside of the 10-inch frame pieces;
screw the crossmember into place [2].
Repeat this step on the other end.
Drill 3⁄16- and ¼-inch holes through
the sides of the frame, 5 inches and
5½ inches on center, respectively,
from the front of the frame. Glue the
footings to the bottom of the frame,
f lush with the sides and 1 inch on cen-
ter from the ends [3].
Drill pilot holes into the center of the
ends of the footings; screw the wheels
into place [4].INSTALL THE
UPRIGHTS AND
UPRIGHT SUPPORTS
Using the drill-glue-and-screw pro-
cess, secure the uprights to the frame
[5]. The uprights should be 4¼ inches
on center from the end, with the screws
driven in from beneath the frame.
Drill, glue, and screw a crossbeam
f lush with the tops of the uprights.
Drill, glue, and screw the supports into
position [6].BUILD A CATAPULTMay/June 2022 65