I looked around the web and could not find where anyone had created the little adapter that goes between the keycap and SMK short-stem keyswitch on an Apple IIe keyboard that uses SMK short-stem keyswitches. I needed three of them to finish refurbishing my first-gen Apple IIe. There are a few places that you can buy them online, but shipping is going to be a lot for such a small part, so I thought it was an easy enough object to design myself.
To install the adapter, first, press it into your keycap, then press the keycap and adapter onto the SMK short keyswitch post. Be careful not to break the adapter off inside your key cap.