F1 Ballista

This is the F1 Team's Project Ballista using wood studs, rope, canvas material, and other items.

Supplies

19 ⅓ feet of 2x4 (The Correct Measurements are 1.5x3.5x8) Wood Studs/Planks

26 feet of ¼” diameter Braided Polypropylene Rope

3 x 9 inch piece of Canvas

Step 1: Preparation - Cut the Necessary Wood Studs

a) 1 - 4 feet in length of the 2x4 wood stud for the Main Body of the Ballista.

b) 2 - 38 inches in length of the 2x4 wood stud for the Base Legs.

c) 2 - 25 inches in length of the 2x4 wood stud for the Top & Bottom of the Main Frame of the Ballista.

d) 1 - 14 inches in length of the 2x4 wood stud for the Arms of the Ballista

e) 4 - 12 inches in length of the 2x4 wood stud for the Support Columns used in the Frame of the Ballista.

Step 2: Preparation - Cut the Necessary Length of Rope

a) 2 - 8 feet in length of the rope for the Torsion Bundle.

b) 4 - 30 inches in length of the rope for the Drawstring (attaching from the Arms of the Ballista to the Pouch)

Step 3: Preparation - Cut the Necessary Canvas Material

a) 1 - 3x9 inch piece of Canvas for the Pouch

Step 4: Preparation - Body of the Ballista

Take one of the 25-inch long wood studs meant for the Main Frame and lay it flat on the workbench, the longest side facing you.

Step 5: Preparation - Body of the Ballista

Mark a crosshair point at 1.75 inches up from the corners closest to you then 3.875 inches toward the center of the wooden stud. These will be used to slot the torsion bundles in later on.

Step 6: Preparation - Body of the Ballista

Then drill a 1.5-inch diameter hole using the center of the crosshairs.

Step 7: Preparation - Body of the Ballista

Repeat steps 4 - 6 for the other 25-inch wood stud.

Step 8: Preparation - Body of the Ballista

Set the cut 25-inch wood studs aside for later

Step 9: Preparation - Support Columns

Take one of the 12-inch wood studs meant for the Support Columns used in the Frame of the Ballista.

Step 10: Preparation - Support Columns

Set your pocket hole jig for a 2x4 stud and adjust the drill bit for the proper length for the stud.

Step 11: Preparation - Support Columns

Slide in the 12-inch wood stud into the pocket hole jig and drill two holes using the outer two drill slots on the pocket hole jig.

Step 12: Preparation - Support Columns

Flip the 12-inch wood stud and drill 2 holes on the SAME side as step 14.

Step 13: Preparation - Support Columns

Repeat steps 9 - 12 for the rest of the 12-inch wood studs.

Step 14: Preparation - Base Legs

Take one of the 38-inch wood studs meant for the Base Legs.

Step 15: Preparation - Base Legs

First, designate which part of the 38-inch wood stud is the Top and the Bottom. The Top will be the part that connects to the Main Body of the Ballista and the Bottom will be sitting flush with the floor. (If the Top does not sit flush with the body of the ballista, flip it around)

Step 16: Preparation - Base Legs

Start with the Top by turning the stud so the longest side is parallel to your body.

Step 17: Preparation - Base Legs

Then turn it on its side and mark 2.9 inches down then to the other side 1.5 inches over to the edge of the plank. This is to cut off 29 degrees from the wood stud so it will fit the body of the ballista.

Step 18: Preparation - Base Legs

Connecting the points with a line will result in a triangle, line it up with the 4-foot wood stud to see whether it is flush with the Body of the Ballista.

Step 19: Preparation - Base Legs

Use the line drawn from the step above as a guideline on where to saw to create that angle. After sawing the line down, the stud should now form half a trapezoid.

Step 20: Preparation - Base Legs

Flip the stud around to cut the other side however this time mark 0.8 inches down from the top left corner then across 1.5 inches.

Step 21: Preparation - Base Legs

Connect the two points together to form the triangle, then use it as a guideline like in step 22 to saw off the excess wood.

Step 22: Preparation - Base Legs

Connect the two points together to form the triangle, then use it as a guideline like in step 21 to saw off the excess wood.

Step 23: Preparation - Base Legs

The 38-inch wood stud should look like a trapezoid prism and that is the Base Leg finished.

Step 24: Preparation - Base Legs

Repeat steps 14 to 23 for the 38-inch wood stud to make the other Base Leg.

Step 25: Preparation - Ballista Arms

Take the 14-inch wood stud meant for the Arms of the Ballista.

Step 26: Preparation - Ballista Arms

Flip the 14-inch wood stud so that the 3.5-inch side faces up.

Step 27: Preparation - Ballista Arms

From the side closest to you, draw a line 1.75 inches up from the side wood stud’s edge closest to you to form a line down the middle of the stud parallel to the 14-inch long side.

Step 28: Preparation - Ballista Arms

Then use the guideline drawn in the previous step to cut the stud in half to be used for the Arms.

Step 29: Preparation - Ballista Arms

Take one of the 1.5x1.75x14 inch wood studs and lay it parallel to you with the 1.75x14 inch stud side facing you.

Step 30: Preparation - Ballista Arms

From the left side on the 1.5x14 inch side go 0.5 inches to the right then down 0.5 inches and make a dot with a pencil. And connect the dot to the edge with a straight line.

Step 31: Preparation - Ballista Arms

Go back to the same corner and go 1.5 inches to the right and add a point.

Step 32: Preparation - Ballista Arms

Connect the point with the top of the line to form a triangle.

Step 33: Preparation - Ballista Arms

Use the triangle guideline to cut the triangular piece out.

Step 34: Preparation - Ballista Arms

Then repeat steps 29 - 33 for the other 1.5x1.75x14 inch wood stud.

Step 35: Preparation - Canvas Cloth

For each corner, go 0.5 inches towards the center of the Canvas then up 0.5 inches to the opposite side and mark a point. This should result in 4 dots at each corner. Using the 4 four dots make a 1/2 inch diameter hole at each dot.

Step 36: Assembly - Body of Ballista and Base Legs

Take the 4-foot wood stud and lie it flat with the 1.5-inch side facing up.

Step 37: Assembly - Body of Ballista and Base Legs

Place one of the 38-inch wood studs on the 1.5-inch side of the 4-foot wood stud. Make sure there is a gap of 3.5 inches from the left. This will be where the front will fit snug into the mainframe.

Step 38: Assembly - Body of Ballista and Base Legs

To connect the Base Arms use wood glue and two wood screws.

Step 39: Assembly - Body of Ballista and Base Legs

Flip the 4-foot stud around and do the same process for the other side making sure there is a 3.5-inch gap from the edge of the top of the 4-foot stud and the closest side of the legs.

Step 40: Assembly - Body of Ballista and Base Legs

With that done, you should be able to place the Body of the Ballista with the Base legs on the floor and the Base Legs should sit level with the floor. Set the Body aside.

Step 41: Assembly - Main Frame and Body of the Ballista

Lay the 25-inch wood stud on the workbench so that the 3.5-inch side faces up.

Step 42: Assembly - Main Frame and Body of the Ballista

From the sides, go 10.75 inches toward the center from both sides. Then draw a line from the top of the plank to the bottom so that it should look like 2 lines in the center of the plank, 3.5 inches apart. Then draw another line 9.25 inches from the side to center, making sure the lines just draw are parallel to each other.

Step 43: Assembly - Main Frame and Body of the Ballista

Place the 2 Support Columns in between the two parallel lines leaving a 3.5-inch gap on the internal sides of the Support Column. Make sure the pocket holes are facing out.

Step 44: Assembly - Main Frame and Body of the Ballista

Then use a wood screw to secure the Support Column to the 25-inch wood stud utilizing the pocket holes. Wood glue is optional to secure the pieces.

Step 45: Assembly - Main Frame and Body of the Ballista

Slide the front half of the Body of the Ballista into the 3.5-inch gap. This should sit flush with the Support Columns on either side of the Body. Use the two wood screws and wood glue to secure the Body with the Main Frame of the Ballista.

Step 46: Assembly - Main Frame and Body of the Ballista

Then place the two remaining Support Columns on the edge of the 25-inch wood stud and make sure there is no part of the Support Columns that stick over the edge. Then make sure that the pocket holes are facing out for the convenience of putting the screws in.

Step 47: Assembly - Main Frame and Body of the Ballista

Then secure the outer Support Columns with wood screws again utilizing the pocket holes.

Step 48: Assembly - Main Frame and Body of the Ballista

Place the last 25-inch wood stud on top of the four Support Columns and secure it with the wood screws and using the pocket holes.

Step 49: Assembly - Torsion Bundle and the Ballista Arms

Take one of the 8-foot long rope for the Torsion Bundle and two 1/4-inch rods (preferably 1/4-inch diameter, 5.5-inch long bolt).

Step 50: Assembly - Torsion Bundle and the Ballista Arms

Make 3 loops around the two bolts resulting in 6 strands of rope. The 2 bolts have to be 15 inches apart from each other. Then tie a knot with the two ends of the rope. (If possible, add more loops to increase the launching power of the ballista if it fits in the 1.5-inch diameter hole.)

Step 51: Assembly - Torsion Bundle and the Ballista Arms

Turn one of the bolts sideways, making sure that the loops do not slide off, to fit it into the two 1.5-inch diameter hole to create the Torsion Bundle.

Step 52: Assembly - Torsion Bundle and the Ballista Arms

Start turning the top bolt towards the center of the ballista to start creating torsion. Before the Torsion Bundle gets too tight, slot one of the Ballista Arms into the Torsion Bundle with the triangular notch facing toward the front of the ballista.

Step 53: Assembly - Torsion Bundle and the Ballista Arms

Repeat steps 50 - 52 for the other Torsion Bundle and Ballista Arm.

Step 54: Assembly - Drawstring and Canvas Pouch

Wrap one of the 30-inch ropes twice around the triangular divet then attach to the same side bottom hole of the Canvas Pouch with a knot. The wrap another 30-inch rope twice around the Ballista Arm beside the other rope, then attach the rope to the same side top hole of the Canvas Pouch with a knot.

Step 55: Assembly - Drawstring and Canvas Pouch

Repeat step 54 for the other remaining side of the Ballista and You Are Done.