Hi guys! in this instructable I will show you how I designed and printed my very own pocket Slingshot.
Pls note that this is my first intractable and that I don't have much experience in reporting what I do, so pls let me know what I should improve :D.
Pls, Remember that slingshots can be dangerous toys. This one in particular will turn out to be more powerful than a commercial slingshot so be responsible on what you will do with it ! Thank-you !
Step 1: Design and Planning
The 3D model was fully designed in Fusion 360. I'm not a pro at it so I didn't use any fancy tools or functions meaning that I limited my self in drawing 4 simple sketches and then extruded each sketch to length.
Since I wanted the slingshot to shoot anything big enough to fit it I decided to go for a 40 mm diameter which is wide enough to fit small objects like pen caps, small screws and anything else that can make a good bullet to shoot.
I want my slingshot to be as cheap to make as possible so I will use normal size balloons as the pouch.(Not the water fight one's!)
To secure the balloon I designed an embedded ring in the inner wall that makes a snug slot for the thick rubber ring of the ballon. (It will take a while and a lot of effort to fit the balloon over the inner wall, but after that it will be a long time before you'll have to change it again.)
Since the only thing keeping the two piece together is friction I decided to create a better locking mechanism.
I used two small pins in the inner component to lock with the outer component with just a small turn of the two granting a solid and strong fit that does not come apart when tensioning the pouch.
One other important thing to note is that I left a small gap between the outer and inner piece that let the rubber stretch and move freely.
At this point the slingshot would already have been functional, but I decided to take it one step further by adding the gear like teeth on the outer wall of the external component. This features increases the grip and makes it a bit more good looking :).
After this I used the fillet and chamfer function to smooth the edges and finish the job and then I exported the .stl model to slice it with Cura.
Step 2: Slicing and General Settings
I'm currently using a Anycubic Kossel Delta 3D printer which uses Cura as it's slicer.
The 2 components were exported and then imported separately so I took my time to space them correctly on the build plate. ( Note that the slingshot is printable without support material ! :D)
I'm using the following settings (only important ones):
Material: Yellow PLA
0.1mm layer height (normal quality)
50 mm/s print speed
10 mm/s print speed first layer
Build plate adhesion : Brim (8mm)
Note: All the other values were kept the same as default so you should already have them.
Step 3: Assembly
The print came out perfect and all the pieces were well defined.
It is a very tight fit between the two components so you might want to work with it a little bit.( maybe a little sanding, but just repeatedly fitting and unfitting them should make them looser)
To fit the balloon over the inner piece I found out that is is easier to cut the balloon's neck away first, fit the balloon's large part over the the inner component and over the slot this rubber ring, and then roll the remaining neck of the ballon it a ring and placing it in the apposite place to lock the pouch in place.
Might require some effort, but the exchange of pouches doesn't happen very often.
After the ballon/ pouch is installed you can go ahead and fit the two components together and locking them and finally have your very own pocket slingshot !
Files Now available on Thingyverse!