How do I make a cylinder with different diameters (and fill it)

[suquet_paul]

I've found the easiest way to create a cylinder with different size ends to be create a circle construct a plane above the first and create a second circle on this second plane, then use the LOFT feature to connect the two. 

My problem now is, how do I make this new body a filled one. I cannot for the life of me find something as simple as "fill". I see there's a way to thicken the walls of this cylindrical body up but that does not go far enough to fill the whole thing. I thought it'd be a simple thing and asked in the same forum post about creating the body itself and was instead asked to create a new post. I suppose there isn't something as simple as "fill" and this is either not possible with the loft feature or something else.

I'm seeking to reproduce a small plastic component to 3D print. 

  The base is 12mm in diameter x 2.25mm thick. The "coned" section on top of the base is 16.75mm tall, the thicker part in the bottom is 9.6mm in diameter while the top is 7.5mm in diameter. Also note there is a square extrusion in the bottom 10mm to fit into its switch. 

The way I eventually made this part was using the chamfer function. Made a symmetrical cylinder and chamfered one of the two sides. But as a feature of this chamfer function (I guess) the diameters kept getting shrunken and had to go back several times to adjust chamfer numbers to seemingly random parameters until I got the diameters on both ends of the cylinder close enough. So, I have solved it for me, this time, and want to learn a way to do this without all the guesswork. It seems like the loft option would be the one, but I need the body to be filled for it to be valuable to my purposes.

Is there a better way to build what I needed than what I did?  

[Warmingup1953]

Revolve seems to be the obvious way here....Have you considered simply sketching 1/2 of the desired cross section?

[suquet_paul]

I did try revolve. And it would've been a useful trick. And that's the one, well then that's the one. But it seemed a little counterintuitive for such a powerful software that the best way of achieving a cone was for the human behind the keyboard to do slicing before inputting calculated dimensions into the software.

So, in a word - yes, revolve does the trick. 

[evanp4509U4JZ]

You can create the inside and the outside and seal the ends with surfaces and use the boundary fill function.

[Fabbunny69]

Forgive me if I am misunderstanding the issue but loft creates a sold feature for me. My test file is attached.