We wanted to make a crossbow fun and unique, and after a bit of deliberating, we came up with this hybrid of a canon/tennis launcher and a crossbow!

Supplies

62''x4'' plywood planks: 2 9in, 3 12in, 1 18in

PVC pipe : 2 12in (one must be a bit small in diameter)

Foam : 1 inch

3D printer : 12 3D printed parts

Glue : We used hot glue

String : 2 40in string

Tools : We used machines such as a drill press and band saw however you may use whatever is on hand

Step 1: 3D Print Parts

Start by 3D printing the following parts of the crossbow, LINK to CAD file for the parts

Trigger Pieces (2)
Arm hooks (2)
Wooden dowels (2)
Trigger dowel (4)
Tennis ball pusher (1)
Rubber band attachment (1)

Step 2: Handle

Gather 1 2''x4'' plywood plank that is 12in in length. Cut piece in half and cut slant on one end (48 degree angle)

cut off triangular shape (0.375in thick, and at a 48 degree angle as shown above) on the slanted side's end. tip of triangle should be 6.35in by4.7in by 4.3in

repeat on other half

Step 3: Base

With the 18in wood piece, cut out a rectangular hole (3.6''x0.7'') that is in the center, and point 0.7in off of the bottom.

Cut out an 8in rectangle (.75in thick) at the other end of the plank, as in above

Using your foam, cut out an 8in rectangle that is the same thickness (.75in). Shape the foam to have a curve in the middle, wide enough for the pvc pipe to fit in nicely.

Attach to the cut off part (via glue), as seen above

Step 4: Bottom Arms

Bottom Arms: Grab 9in plank, cut a x7'' rectangular hole in the center of one end (as seen above). cut a small angle out (2in) as seen above. Drill a hole in the center of the end you but the rectangle from (.75''x.75'' for reference).

Make 2

Step 5: Top Arms

Top Arms: Gather 12in planks, cut out a rectangular piece at the center of one end (as seen above), 3.4''x.7''. Drill hole in the center of rectangle piece (.75''x.75'' for reference)

Make 2

Step 6: Attaching Arms

Attach the pieces together.

Take 12in PVC pipe (bigger diameter one), glue down to foam piece.

Take the bottom arms, glue down the slanted sides at the end of base (as seen above). Take top arms, line up the holes (as seen above), place wooden dowel inside the holes

add glue to secure.

Glue rubber band hook at the top of the bottom arm

Step 7: Smaller PVC

Grab a second 12in PVC that is slightly smaller in diameter then the first (should be able to go inside the first one comfortably). put the smaller PVC inside the the bigger one, leaving a little to poke out the bottom.

cut out a circle from a piece of paper (or cardboard) and attach it to the end that is inside the bigger PVC

place tennis ball pusher at the end (you'll tie it later, do not glue)

Step 8: String

Drill 2 small holes at the other end of the top arm (as seen above), cut 2 40in string and weave one end through drilled hole and the other end through the tennis ball pushed.

pull the ends through until you are satisfied with the string, the tightness and tension. Tie the string on each end tightly

(image in previous step)

Step 9: Rubber Bands

Glue down rubber band attachments on the top end of PVC pipe

Weave in one end of rubber band through rubber band hook, weave other end through the rubber band attachment then weave that end through the hook. repeat 5 times (or more as you'd like)

Step 10: Attaching the Handle

Grab one half of the handle and place the trigger pieces (as seen above) 4 small dowels inside (through the holes) and glue to secure. line up the other side and glue the pieces together.

line up trigger and hole with the hole of the base, handle should be facing out, glue handle to base.