As others have said, we are happy to help, but it’s in your own best interest for us to not hand you the answers. We are unable to help without knowing concrete problems you are facing (questions you might have or places that you might be getting stuck) that we can help you work through.
This may or may not help you… it’s specifically for #4. [Edit] But also works with #12.
This is the feature tree for doing that particular part, at least when I did it. Took me about 15 minutes, some of which was getting into “Onshape mindset” when I’ve been arguing with Inventor for most of the day (about it being slow on a fairly nasty part).
That said, if there’s a particular part you want to ask questions on, you will need to ask–and you’ll want to show evidence that you’ve tried. (See my last post for why…)
I have shared two files with you. They are the parts you have graphed with 1 cell to 1 inch ratio. I advise you to look at how they are made and create them yourself. Also you can DM me on our team discord with any questions.
I have gone with the wrong scaling because I would like it if you would work out how to scale the parts on your own. The only tools you will need to create this is the sketch and extrude tool. Start by doing the largest part of your shape and then you can work off of it.
This, in my opinion, is the key idea/skill. You’ve got to look at your part and see how some or all of it is some 2-d shape that is “extruded” (stretched out) in the third dimension. This can either be an additive operation or a subtractive one.
So, for example, a cylinder is a (2-d) circle, stretched in the 3rd dimension. You could add this to a shape or you could subtract it to get a hole.
As you are building up your part from these extrusions, remember that the plane you draw the 2-d shape on (the “sketch” in OnShape-speak) can be different each time. For example, imagine you are designing dice. You would probably start with a square, extrude it to a depth equal to its side length to create a cube and then you might create six more sketches, one on each face of your cube to create the “dots”. Your first one might be one circle located in the center of the face and extruded in subtraction from the face of the cube to some small depth. You’ve just created the “1” side of the dice. Then on to the other five sides.
As you gain experience you will see that “rotate” is an alternative to extrude. Depending on what line you use as the center of rotation you should be able to see how you could turn your circle into a sphere or a torus.
As others have pointed out, each of your three objects CAN be created with just two extrusions, and it can be a good skill builder to try to see how that is true, that MAY not be the “best” way to design the object. People’s opinion on what the “best” way is may vary, but I would put at the top of the list of considerations “how easy is it for the next person to understand why you designed the part the way you did”.
Let’s imagine you are designing a part that a motor and a square sensor mount to. Each needs 4 bolt holes. Let’s imagine both need the same size bolt holes. One way to design the part would be to individually position and size each of the 8 holes. If the size of the holes needs to change that’s a pain, so you could size just one hole and say the other 7 are “equal” to it. Now change one size and they all change. Maybe that’s too far the other way. Probably best to size one motor hole and one sensor hole. Now what about positioning the holes? There is probably some inherent symmetry in how your holes can be positioned. The motor holes are probably evenly spaced around a circle of some diameter, OnShaoe can do this. So if the next iteration of the design has a motor has a different “bolt circle”, one change and done. Similarly for the square sensor, a rectangular bolt pattern is probably in order.
A huge part of the design process is developing the skills to see/recognize these spatial relationships.