This is a catapult that I designed using Fusion 360. Its one of my first projects using that CAD software so please let me know if you notice anything that needs to be added or improved. This design is the result of about 5 different versions that I printed. I tweaked details in between versions to make it stronger, more efficient, etc. I finally thought it was worthy enough for Thingiverse, so here ya go :D
(oh dear lord the filament I had to sacrifice to design this, as a broke college student, tips welcome but not expected, I'd use the money for more filament which would allow me to design more cool stuff, but again not expected)
PARTS NEEDED FOR ASSEMBLY:
1x Bottom Frame
2x Stop bar half
2x Bottom bar half
1x Throw bar
1x Cradle of your choice
All you need to be able to put this together is some superglue and various sizes of rubber bands. You need to glue the uprights to the frame, the cradle onto the throw bar, and the bar halves together. It should be easy enough to put together just by the pictures, but don't be afraid to ask questions!
I'll try to add more specialized cradles in the future. If you do decide to print another cradle after already assembling the parts, then you will need to print another throw bar assuming you've already glued a cradle to the existing one.
These parts print well on my Maker Select V2.1 and need no sanding, but depending on how accurate your printer is you may need to sand a part or two.
TIPS ON PRINTER SETTINGS:
Obviously 100 percent infill would be the strongest, but I would recommend 40 to 50 percent infill for most of the parts. I would also recommend 3 or more perimeter walls. Also if you have a .4mm nozzle, go for a .2 or .25mm layer height as that is the strongest layer height for that size nozzle.
Be careful when scaling up or down because it also scales the tolerances between the parts and it may force the parts to be too loose or too tight. I haven't tried scaling it, but if you do please report your findings :)
Use supports for the uprights and cradles to support the insertable tabs.
Feel free to give me suggestions or create a remix as I am sure there are still flaws in the design. I am trying to think of different cradle designs, such as one that launches dog treats or another that launches an arrow. If you make a cradle please let me know so I can put a link to the page on here. I'm sure this community can think of some pretty neat things to fling...
The tab at the bottom of the cradle is 13mm by 2mm by 4mm deep. The insert in the throw bar has a .3mm offset around it.
If you print my design please take a picture as I would LOVE to see it...
Double quarter- launches two quarters!
Basic rectangle- could hold various things, 27.5mm by 22.5mm capacity
10mm Marble- holds a 10mm (1/2 inch) marble