Making The Stem

From here, the story changes. Cherry switches have a plus-shaped stem that's 4mm long and 1.17mm wide, but other brands of switches have their own dimensions. It's up to you to do research on the dimensions!

For this tutorial, I will use the dimensions shown in the image above, as well as a stem diameter of 5.5mm.
First, start with a circle with diameter 5.5mm centered at the origin (this should also be the center of the keycap if you centered the loft profiles on the origin!)

Next, use the Rectangle tool to draw out the plus shape of the stem, making sure the rectangles are dimensioned correctly to your keyswitch (I recommend using Center Rectangle here!)

Once you have that, finish the sketch and extrude the circle (EXCLUDING THE RECTANGLES!) downwards. The length of the extrusion depends once again on your switch, but 6-8mm tends to work out for me.

Once you finish that extrusion, your switch should nearly be done! Go ahead and gawk in amazement!

But this is only the easy part...