Grade 8 Enriched Math Catapult Project 2012 Step by Step Instructions to building a catapult
Grade 8 Enriched Math Project INSTRUCTION SHEET FOR CATAPULT Procedures, materials and tools: below is a step-bystep list of instructions to assemble a catapult. A letter labels all parts included in the assembly.
#1 - PREPARE THE WALLS (C) AND WALL SUPPORTS (D) 2 pieces of plywood (Walls C) 2 pieces of wood (Wall Supports D) Measuring tape Adjustable square Supplied compass Straight edge 3/8 diam. brad point drill bit Clamps (2) 100 grit sand paper #1. Place the sheets of plywood (Walls C) one at top of the other on your workbench, align holes. #2. Make sure the shortest side runs parallel to your body and the holes are to the right. #3. Draw a horizontal line 75 mm above and parallel to the base. #4. Draw a vertical line 40 mm from the right side and parallel to the right side. #5. Using the holes as a centre point, draw an arc with a 750 mm radius using the supplied compass. #6. From the centre of the 3/8 holes, draw a 45-degree angle to intersect the arc. Use the adjustable square and the straight edge. #7. Using the intersection of the arc and the 45-degree line as a new centre point, draw a series of 9 points along the arc, 50 mm apart. #8. Align the sheets of plywood and clamp them together. Put one clamp on the left side and the other at the base. Drill 3/8 diam. holes through both pieces of plywood at each of the 10 points on the arc. #9. Place the sand paper over a block of wood. #10. Lightly sand over the edges and the area of the holes.
#2 - PREPARE THE STOPPER (G), BUNGEE SUPPORTS (F) AND THROWING ARM (H) 1 throwing arm (H) 2 pieces of wood (Bungee Supports-F) 1 stopping arm (G) Measuring tape Adjustable square 3/8 diam. brad point drill bit (power hand drill) 100 grit sand paper #1. Place the stopper (G) flat on the workbench. #2. Draw the lines from the drawing below onto one end of the stopper (G). #3. Place the two bungee supports (F) flat on the bench. #4. Draw the lines from the drawing plan #RD005 onto both ends of the bungee supports (F). The plan indicates one hole at each end but two holes at each end are drilled. Instead of 32 mm only draw 2 lines 20 mm from each edge. Drill 4 holes 3/8 diam. #5. Place the throwing arm (H) flat on the workbench. Starting at one end of the throwing arm, measure 1 metre and draw a line across the face of the throwing arm. #6. Draw a line 32 mm from the long side of the throwing arm to intersect the 1 metre line. Drill a 3/8 diam. hole. #7. Place the sand paper over a block of wood. #8. Lightly sand over the edges and the area of the holes. #3 - PREPARE THE TRIGGER (I-8 and I-9) Cordless drill - electric #2 Robertson bit driver 3 mm drill bit (power hand drill) 75 mm long wood screws, flat head, #8 Two pieces of wood (I-8)
One piece of wood (I-9) 100 grit sand paper #1. Place I-8 and I-9 flat on the workbench. #2. Place a #2 Robertson bit in the chuck of the cordless drill. #3. Place two 75 mm long screws in two of the 4 mm holes (same side) of I-9, and drive them partially in the wood. #4. Place one of the shorter pieces of wood (I-8) vertically in the bench vice with the flat end on top. #5. Hold the end with the screws (I-9) over the end of the wood in the vice, make sure they align and drive the screws in with the cordless drill. #5. Repeat with second I-8. #4 - PREPARE THE FOOT (A) Adjustable square 3/8 diam. brad point drill bit (hand power drill) Sand paper 100 grit Two pieces of wood (A) #1. Place both pieces of (A) flat on the work bench (make sure 64 mm is the height of item A). #2. Measure 32 mm from one end and 32 mm from the side. Mark point of intersection. #3. The intersection of these lines is the centre of the hole. #4. Using the 3/8 diam. drill bit in the chuck of the drill press drill one hole in each foot (A). #5. Place the sand paper over a block of wood. Lightly sand over the edges and the area of the holes.
#5 - SUB-ASSEMBLY: WALLS (C) TO WALL SUPPORTS (D) Walls C Wall Supports D Cordless electric drill #2 Robertson bit 2 long, # 8, flat head wood screws (10) #1. Stand one of the wall supports (D) on edge on the bench top. #2. Place one wall (C) next to the wall support (D) so that the drilled hole is at the end closest to you. #3. Align the wall (C) and wall support (D). #4. Drill 5, 2 wood screws through the wall to the wall support, space evenly. #5. Repeat for the second wall in a way that you have one hole on the left and one on the right at the same end. #6 - SUB-ASSEMBLY: WALLS (C) and WALL SUPPORTS (D) TO BASE (B) 3/8 diam. threaded rod (4) 75 mm long 3/8 diam. threaded rods (2) 100 mm long Qty: 8, 3/8 dia. nuts Qty: 12, 3/8 dia. flat washers 9/16 wrench (2) Cordless electric drill # 2 Robertson bit 2 long, # 8, flat head wood screws Throwing arm H Base B #1. Place the cut rod (150 mm) in the 3/8 hole in the throwing arm (H). #2. Place one flat washer on the rod on both sides of the
throwing arm (H). #3. Stand walls (C), facing each other, on their supports (D). #4. Place the walls next to the arm so that the rod fits into both holes. #5. Place a flat washer on rod at both sides of the walls. #6. Thread a nut on both sides of rod. #7. Bring the nuts close to the plywood and tighten slightly. #8. Place the base (B) on the workbench. #9. Place the assembled walls and arm on top of the base. #10. Adjust the position of the walls, so that they are located in the centre of the base. #11. Mark lines on both sides of the wall supports, these lines must be parallel to the sides of the base. #12. Remove the throwing arm from the assembly. #13. Place one wall with its support on the marked lines. #14. Insert the threaded rods through the holes. #15. Place a washer over both ends of rod, thread a nut over both ends and tighten securely. #16. Drill five 2 screws, evenly spaced, from the bottom of the base through the supports. #17. Repeat steps 13 & 16 to secure the second wall in place. #7 - SUB-ASSEMBLY: BUNGEE SUPPORTS (F) AND STOPPER (G) TO THROWING ARM (H) Measuring tape Cordless electric drill #2 Robertson bit Throwing arm (H) 2 long wood screws, flat head, #8 Bungee Support (F) Adjustable square Hinge Four 1/4 bolts, four 1/4 washers, four 1/4 nuts
1/4 brad bit 7/16 wrench Clamp 1/2 wrench One 100mm x 3/8 rod, two 3/8 washers, two 3/8 nuts #1. Place the throwing arm (H) flat on the workbench. #2. Starting from the end opposite to the drilled hole, place the centre of the open hinge on the end of the arm and clamp it in place. #3. Place the 1/4 bit in the chuck of the drill and drill 2 holes to correspond with holes in the hinge. #4. Secure the hinge to the throwing arm with the 1/4 bolts, washers and nuts. Tighten nuts. #5. With the throwing arm flat on the bench, stand the stopper at the hinge side touching the throwing arm. The angle between the 2 pieces of wood MUST be over 90 degrees. #6. Open the hinge and clamp it to the stopper. #7. Drill 2 holes as before and secure with 1/4 bolts, washers and nuts. Tighten. #8. Place the bungee support on the throwing arm so that the hole in the throwing arm and the hole in the centre of the support align. #9. Secure with a 3/8 carriage bolt, washer and nut, tighten. #10. Drill two, 2 wood screws from the support through the arm, make sure you maintain a 90-degree angle.
#8 - SUB-ASSEMBLY: BRACE (E) TO BUNGEE SUPPORT (F) Measuring tape Cordless electric drill #2 Robertson bit Brace (E) 2 wood screws, flat head, # 8 Bungee Support (F) Adjustable square #1. Place the bungee support (F) flat on the bench. #2. Measure and mark the centre, lengthwise. #3. Place the support (F) over the brace (E). #4. Align one end of the brace (E) with the centre of the support (F). #5. Drive two 2 wood screws through the support to the brace. #9 - ASSEMBLY Cordless electric drill # 2 Robertson bit One piece of wood (left from trigger) Two pieces of 3/8 dia. threaded rod Six 3/8 diam. nuts Eight 3/8 diam., flat washers Wrench, 9/16 Wood screws 1 1/2 long, flat head Wood screws 75 mm long Measuring tape Duct tape Pipe insulation 25 mm diam. Utility knife Clamp All your sub-assemblies
Two pieces of wood (A) One piece of wood (G) Two pieces of bungee cord, 4 m long each One piece of pulling rope 2 m long #1. Place the throwing arm (H) flat on the bench. #2. Tape one 3/8 washer on each side of the drilled hole, do not cover hole. #3. Place the base (B) on the workbench. #4. Insert the throwing arm (H) in place, bungee support (F) down, without displacing the washers. #5. Insert one threaded rod through the hole in the walls and arm. #6. Place a 3/8 diam. washer on both ends of the rod. #7. Thread a 3/8 diam. nut on both ends of the rod. #8. Tighten the nuts lightly. #9. Place (A) under the base, one on either side, standing on edge. #10. Align foot with side and end of base. #11. Drill five 2 wood screws from the base through to the foot. #12. Repeat for other foot. #13. Place the brace (E) between the walls, bungee support facing out. #14. Align with edges of walls. #15. Drill, from both sides, three 2 wood screws though the walls to the brace, space evenly. #16. Pivot (raise) the throwing arm until it matches the 45- degree line, hold in place. #17. Insert the stopper, (G) over the arm so that the bottom end is even with the walls. #18. Clamp the arm in position. #19. Drill, from both sides, four 2 wood screws through the walls into the stopper. #20. Remove the clamp. #21. Place the trigger in position, insert the threaded rods in both holes, place a flat washer on ends of threaded rods, thread a nut on ends of threaded rods, tighten loosely.
#22. Drive one 2 wood screw in the centre of the top of the trigger ¾ of the way in. #23. Attach the pulling rope to the screw. #24. Place piece (J) between the feet 300mm from the trigger end. #25. Align and drive two 2 wood screws from both sides. #26. Raise the throwing arm until it touches the stopper. #27. Clamp the arm to the stopper. #28. Insert bungee cords and knot. #29. Fasten the cup (to hold the ball) to the high end of the throwing arm, leaving enough distance for the trigger with an 2 wood screw. #30. Cut the pipe insulation in half. #31. Spread the insulation open, place one half on the throwing arm and secure with duct tape, place the other half on the throwing arm opposite from the first half and secure with duct tape.