A basic cup shape has many general applications. You can select inner and outer diameters and make them different at top and bottom for a taper in or outwards. The bottom of the cup thickness can also be set. Use Open SCAD to use this file and output the cup shape of your dreams...

I used the sample for a pullup bar with a screw thread that extends to squeeze in a door frame. Also good for stool feet as an example.

There is a mm and then an "inch" unit version of the same file. Inch values need to be divided by 1000 to allow for 3 place decimal places in inches as noted in the parameters list.