Introduction

Here are some step-by-step instructions that walk through the build process for the catapult that Mark makes in his prototyping lesson. If you’re looking for a simpler project, or one that does not require power tools, see the Simple Catapult for Beginners guide.

This is a completely optional resource — NOT a homework assignment! If you're incorporating a catapult into your build and want to start with something similar to Mark's prototype, this may help you fill in the gaps in Mark’s build process.

Remember, Mark figured out how he wanted to assemble this build as he was doing it in the prototyping phase, so it wasn’t planned out perfectly ahead of time. So, you’ll see him do things in the video lesson like add a piece and then decide to remove it later on. We’ve flagged those moments in this document so you can avoid unnecessary work, but you may need to be a bit flexible.

Materials

3/4”x3/4” square wooden dowels
- You’ll need enough length to cut:
  - 2x 5” pieces
  - 2x 7” pieces
  - 2x 7-3/4” pieces
  - 2x 11” pieces
  - 1x 10” piece
- You should be able to do this with 3x 36” long dowels, but you may want to buy a few extra dowels in case you need to remake a piece.
15-20x drywall screws, at least 1” long
1/8” circular metal rod, at least 5” long
- You can also use a circular wooden dowel, but metal is preferred.
Rubber band
Bottle cap

Tools

Pencil
Ruler or set square
Hacksaw with blades that can cut wood and steel
Clamps, a bench vise, or a miter box
Power drill/driver, with:
- A small drill bit that matches the inner diameter of your screws for drilling pilot holes
  - If you bought #6 screws, like those listed above, you’ll need a 3/32” or 9/64” drill bit.
- 1/8” drill bit for drilling your axle holes
- A screwdriver bit to match your screws
- You can also use a separate drill and impact driver instead of a single drill/driver, which is what Mark does.
Sandpaper with a grit count higher than 220, for deburring the metal axle.
Eye protection
Ear protection