Want to shoot cheese at 129+ MPH? Want to shoot marshmallows 225+ feet? Want to shoot banana's on the interstate to slow down your competition? Want a great neighborhood activity outdoors that literally everyone is interested in participating while being socially distanced? This build is for you!

First, I signed up for Mark Rober's inaugural monthly.com class where he challenged us to build a project that relied only on mechanical systems, and had to be involved with food in some way. He also casually said 'if you want to set a world record - be my guest'. I found a world record for 'Farthest marshmallow propelled and caught in the mouth', which lined up perfectly with the challenge for the class.

Second, instructables ran a contest called 'Cheese Speed Challenge'. Assuming at least one astronaut has taken cheese on their mission that's probably the fastest cheese known to man. I'm going to go out on a limb and say that at 129 MPH my cheese will be the speediest of all cheeses in this instructables contest (without even knowing all my competition)

Follow along to see how this world record setting machine was made, and see if you can build one to top mine!

Supplies

1 2x6x12
4 2x4x10
32 x 3.5" screws (I think?)
16 x 1" screws
2 x 1.5" screws
2 x 4.5" screws
2 right angle brackets
Steel Flat Bar ( ~15 inches 1/8x3/4)
86 inches of TheraBand (gold or silver - high resistance)
Duct Tape

Drill
Driver
Bits
Miter Saw
Metal working tools (hacksaw and sander, or Dremel, or grinder)

Projectiles

Step 1: Prototyping

This isn't a step you'll need to do, but it was one I did as part of my class, and feel it's important to capture some of the lessons learned so you can continue to build upon my failures. I used 100% scraps and stuff laying around the house for the prototype other than the eye-hooks, and didn't want to make extra cuts (hence the uneven lengths)

(1) Prototype! We only had a few days to make our builds, and if I had spent more time on this phase I might have been successful back in January. With more lessons learned up front your builds will be more successful too, and you'll learn a whole lot more here than just guessing or doing online research.

(2) I assumed a 'triangle' would be the best shape for the base as you can always make it stable on an uneven surface. That proved to be false, as when I loaded up the elastic bands the devise bent and shifted all the contact to just one single point on the back of the launcher and made it very unstable. Keep your wide point in the rear.

(3) I used 40 lb. exercise bands in the prototype, and was getting ~120 feet consistently (world record was 128 feet). I assumed that by upgrading to 100 lb. bands in the final build that I would easily be beating the record. This proved to be false. I since learned that elastics are able to more quickly return to their original shape when they have a higher surface area compared to the cross section. The 100 lb. bands ended up being worse. Hence why I'm now using Therabands. If I'd stayed prototyping longer I could have saved myself from buying a hand winch, lacrosse mesh, pulley and quick release shackles! You probably don't need this much wood either, but I already had this built when I stepped back down to lower resistance bands...

(4) I was doing this class in January. It's possible that the chilly Utah weather played a factor in the exercise bands not working well enough. Definitely people recommend high quality latex though!

Step 2: Make Your Cuts

(1) Cut the ends of 2 2x4x10's to 45 degrees, but don't take any length off. These serve as the angled supports.

(2) Cut 84.5 inch pieces of each of the other 2x4's. The long pieces we'll use for the vertical supports. We'll use the short cuts for extra bracing. Cut those to 24", and use the scraps for something else.

(3) Cut 2 x 24 inch cuts off the 2x6. The long piece serves as the spine of our base. The shorter pieces are to hold everything together.

Step 3: Screw the Pieces Together

(1) I started by securing one of the 2x6 pieces to the bottom of the angled 2x4s. I used 3 screws in each. 2 from the bottom, and 1 angled from the top. Lay the 2x4s flat on the ground with the angles pointed up for this step.

(2) Next I secured the vertical 2x4 supports to the base. Lay the 2x4s on the ground with the base perpendicular to the ground, and screw from the bottom of the base up into the vertical supports.

(3) I screwed a 2x6 onto the vertical supports to help them maintain a square at this point. Ensure they're square when performing this step! I also placed a 2x4 under this when I secured it. It was important to get this 2x6 lined up with the 2x6 spine in step 5, since I was mounting a hand winch. This might be better served up higher. I also put a screw on the bottom side of it (not screwed in all the way) so that I could quickly secure my measuring spool to it. This is just a creature comfort if you're going to be measuring distances for a record. Not essential.

(4) Next I leaned the vertical supports up against a wall, then brought the angled supports into place and screwed them down. This is where I used longer screws if you have them. Otherwise, you can drill out enough extra for your screws to bite down from the angled supports into the vertical supports (deep countersink). (You could do pocket screws or brackets here too if you want)

(5) I pulled it back away from the wall to continue working. I centered the long 2x6 on the front by the vertical supports first, then secured it with screws. I then centered the rear of the spine on the 2x6 by the base of the angled supports, and secured them with the 1" screws.

(6) Next I secured the additional cross members just based off visually where they would work well to not impede the launch since I was planning on trying several different angles. I like the near 45 degree launch I have, so these could both be moved up for your build to give it more support. Using some clamps really helped me get them where I wanted while keeping things square. An extra set of hands could help quite a bit too.

Step 4: Make the Slingshot

(1) Cut 2x ~7.5" of steel bar. I used a hacksaw, but a Dremel or grinder would work well too.

(2) Drill holes in your steel bars (one on each end). Wider than your screw's shank, but as small as otherwise possible. Center them so that they are the same distance from each side.

(3) Sand off any burrs and ensure they're completely smooth so they don't tear up your bands.

(4) Cut 86" of Theraband. This will allow it to stretch to 3x its original length when firing. This is what most people consider optimal. Making a longer band (and stretching it to the same length) will result in weaker shots, but the band will hold up longer. Stretching them further (by reducing the length of the band) will cause them to wear out faster. You can also taper it for faster shots (but quicker wear). In this case you might need two bands. The crazy German known as 'the slingshot guy' has a great calculator to help with all of this should you like to experiment. I left mine whole.

(5) Tape the end of the band onto the steel bar. The tape won't ultimately be what holds the band in place, but it helps keep it secure while you're handling it. Then roll the band around the bar (I did mine 3 rolls, but many people go much less). It is the contraction of the bands and the friction on them that keeps them in place once secured.

(6) Use 1.5" screws to mount the band to the top of your base. I put one screw through each of the vertical and angled supports so it was about 42 degrees (optimal launch angle). Just center the screws on each 2x4, and sandwich the bands down tight so they're not going to move on you at all. I think doing through bolts would be a better option than screws, but didn't want to run to get them.

Step 5: Fire!

So, I do feel obligated to remind you that slingshots are used to kill small game. They are dangerous to them, and they will be dangerous to you. I'm not a mechanical engineer, and haven't done any safety analysis on this system. You're storing a lot of energy in those bands, and if anything comes free there's a good chance it will be coming right at you (played weather band anyone? It will be like that, but on steroids and possibly with metal attached). I wore safety googles while firing and you should protect yourself too. NEVER point it at anything that you don't mind having maimed!

That being said, I have not actually set the world record with this... yet! We've taken it out 3 days, and everyone has had it hit their lip, but nobody has had it go in yet for 'longest marshmallow propelled and caught in mouth'. The current record is 128 feet, and we're consistently getting ~170 ft. There is seriously no better way to reconnect with an old friend, or make a new one than by saying 'hey, want to attempt a world record this weekend?' Everyone in the park gathers around and wants to know what you're doing, or give it a try.

Yes, I did check the speed of my cheese, and it was 129 MPH. You can see how I did that for free using stuff I already owned by reading through this instructible: Solve for Velocity (without Mark Rober's $89 blanket). You can also see when mounted in the back of your truck it could be used as an excellent Mario Kart deterrent. Banana anyone?

If I were to do it again I think I might leave the vertical supports a little longer so I could use an even longer band to hopefully get a higher 'muzzle velocity' while maintaining a good launch angle. The whole thing is pretty overengineered at this point since I'm not using the 100 lb exercise bands. I might use slightly smaller cuts of wood. This thing is pretty heavy! I would probably look at doing a taper on the bands. Maybe use a leather pouch to launch the projectiles, or some nylon webbing. Maybe add some wheels to the front so that I could move it around easier, and go a little wider on the base just so it's a little more secure. I'd love to see where you take this to make it shoot even further!

Thanks for reading and please consider subscribing to my YouTube channel to see when I've actually caught the 'mallow in my mouth! You just got Nerd Sniped!